diff --git a/go.mod b/go.mod
index 70cf516..7fbd78b 100644
--- a/go.mod
+++ b/go.mod
@@ -15,6 +15,7 @@ require (
 	go.uber.org/atomic v1.11.0
 	golang.org/x/crypto v0.54.0
 	golang.org/x/sys v0.47.0
+	gopkg.in/yaml.v3 v3.0.1
 	modernc.org/sqlite v1.54.0
 )
 
@@ -58,7 +59,6 @@ require (
 	golang.org/x/text v0.40.0 // indirect
 	google.golang.org/protobuf v1.36.11 // indirect
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 	modernc.org/libc v1.74.3 // indirect
 	modernc.org/mathutil v1.7.1 // indirect
 	modernc.org/memory v1.11.0 // indirect
diff --git a/internal/web/README.md b/internal/web/README.md
index ce0fb9a..db4c146 100644
--- a/internal/web/README.md
+++ b/internal/web/README.md
@@ -4,7 +4,9 @@
 
 Part of the single `openfsd` binary (`cmd/openfsd -web`; default runs FSD + web). Shares `internal/db` with the FSD server; live connection state comes from the FSD service HTTP API (`FSD_HTTP_SERVICE_ADDRESS`, default `http://127.0.0.1:13618`).
 
-JSON under `/api/v1` for external tools and map polling. First-party UI is a progressive-enhancement MPA: form login sets a signed **HttpOnly session cookie**; `/api/v1` dual-accepts that cookie **or** a Bearer access token. External tools should use Bearer API tokens.
+JSON under `/api/v1` for **operator automation** and map polling. First-party UI is a progressive-enhancement MPA: form login sets a signed **HttpOnly session cookie**; `/api/v1` dual-accepts that cookie **or** a Bearer access token. Operators automating the same workflows as the UI should use **Bearer API tokens** (not browser session cookies).
+
+**Blast radius:** Admin-minted API tokens currently carry an **Administrator-equivalent** network rating claim and full config/token power. Treat them as operator credentials with admin blast radius until fine-grained scopes exist—not as multi-tenant “third-party app” keys.
 
 ### First-party HTML pages (no-JS primary path)
 | Page | Routes | Authz |
@@ -22,7 +24,7 @@ JSON under `/api/v1` remains for external consumers and map polling. Session dua
 ### Airport editor validation
 
 - **Live client:** JS `parseAPT` / `parseAIR` + soft cross-file warnings (dep ICAO, aircraft far from field) on the Validate tab.
-- **Confirm with server (optional):** `POST /api/v1/editor/validate-apt` and `POST /api/v1/editor/validate-air` with JSON `{"text":"…"}` (Admin, dual-accept Bearer | cookie; CSRF when cookie). Response is standard `APIV1Response` with `data.errors`, plus `icao` / `surface_count` or `aircraft_count`. Transient request body only — never written to disk/DB.
+- **Confirm with server (optional):** `POST /api/v1/editor/validate-apt` and `POST /api/v1/editor/validate-air` with JSON `{"text":"…"}` (**Instructor1+**, dual-accept Bearer | cookie; CSRF when cookie). Response is standard `APIV1Response` with `data.errors`, plus `icao` / `surface_count` or `aircraft_count`. Transient request body only — never written to disk/DB.
 - **Handoff:** download `.apt`/`.air`, then load on `/sweatbox` (no automatic push from editor → live session).
 - Design: `docs/design/apt-air-editor.md`. JS unit tests: `webjs/` + `bash scripts/check-webjs.sh`.
 
@@ -60,9 +62,48 @@ Most endpoints accept a valid JWT access token:
 ```
 Authorization: Bearer <access_token>
 ```
-- **API tokens** can be created via `/api/v1/config/createtoken` with a custom expiry date. See the **Server Configuration** menu in the frontend UI to generate one.
+- **API tokens** can be created via `/api/v1/config/createtoken` (Administrator) with a custom expiry date (max **90 days**). See the **Server Configuration** menu in the frontend UI to generate one.
+- `createtoken` responses include additive `recommended_api_version`, `api_version_min`, and `api_version_max` so clients can pin the microversion header.
 - Bearer-authenticated clients do **not** need CSRF (CSRF applies only when the request is authenticated via the session cookie).
 - Dual-accept: a **valid** Bearer token wins over a session cookie; a garbage Bearer header does **not** disable CSRF if the session cookie is what authenticates the request.
+- **Operator automation:** prefer minted API tokens over `/auth/login` or `/auth/refresh`. Tokens are admin-equivalent until scopes exist—store as secrets; rotate on compromise via secret reset.
+
+---
+
+## API versioning
+
+openfsd keeps a durable URL major **`/api/v1`**. Rare **breaking** changes on **Stable** enveloped routes introduce a date **microversion** selected with the request header:
+
+```http
+OpenFSD-API-Version: 2026-07-28
+```
+
+| Rule | Detail |
+|------|--------|
+| Canonical form | `YYYY-MM-DD` after normalize; also accept `1.YYYYMMDD` and `latest` (→ max) |
+| Default when omitted | **`max_version` (current)**; response sets `OpenFSD-API-Version-Defaulted: true` |
+| Production clients | **MUST** send `OpenFSD-API-Version` with a supported pin |
+| Additive changes | Free (new fields/endpoints); clients must ignore unknown JSON keys |
+| Breaking changes (Stable) | Bump microversion; keep old pins for the support window |
+| Envelope body `version` | Always major `"v1"`; microversion is **header-only** |
+| Response headers | `OpenFSD-API-Version` (effective), `OpenFSD-API-Min-Version`, `OpenFSD-API-Max-Version`, optional `OpenFSD-API-Version-Defaulted`, `Vary: OpenFSD-API-Version` |
+
+**Discovery (public, version-agnostic — never 400 on a bad pin):**
+
+| Method | Path | Notes |
+|--------|------|-------|
+| GET | `/api/v1` | Same discovery payload as `/versions` |
+| GET | `/api/v1/versions` | `min_version`, `max_version`, `versions[]`, `openapi` |
+| GET | `/api/v1/openapi.json` | OpenAPI 3 from embedded YAML |
+| GET | `/api/v1/openapi.yaml` | Canonical embed source |
+
+Canonical OpenAPI file: `internal/web/openapi/openapi.v1.yaml` (`//go:embed`). No mirrored copy under `docs/`.
+
+**Outside microversion reject:** `/api/v1/data/*`, `/api/v1/fsd-jwt`, auth login/refresh, discovery, OpenAPI. Resource groups (`/user`, `/config`, `/fsdconn`, `/sweatbox`, `/editor`) reject unknown/invalid pins with **400** envelope.
+
+**Stability tiers:** existing enveloped user/config/fsdconn/editor routes are **Stable** (goldens under `testdata/api_v1/<pin>/`). New expansion routes may ship **Provisional** (shape may change without a microversion bump while Provisional). Design: `docs/design/rest-api-versioning.md`.
+
+Baseline pin (first supported): **`2026-07-28`**.
 
 ---
 
@@ -100,6 +141,29 @@ Common HTTP status codes:
 
 ## Endpoints
 
+### Discovery & OpenAPI
+
+#### GET /api/v1 and GET /api/v1/versions
+Public discovery of supported microversions (same payload on both paths). **Version-agnostic:** a bad `OpenFSD-API-Version` does not cause 400.
+
+**Response (200 OK)** `data`:
+```json
+{
+  "major": "v1",
+  "min_version": "2026-07-28",
+  "max_version": "2026-07-28",
+  "versions": ["2026-07-28"],
+  "header": "OpenFSD-API-Version",
+  "default": "max",
+  "openapi": "/api/v1/openapi.json"
+}
+```
+
+#### GET /api/v1/openapi.json and GET /api/v1/openapi.yaml
+Public OpenAPI 3 document (embedded). Version-agnostic.
+
+---
+
 ### Authentication
 
 #### POST /api/v1/auth/login
@@ -410,7 +474,9 @@ Upon successfully calling this endpoint, this effectively invalidates *all* prev
 ---
 
 #### POST /api/v1/config/createtoken
-Create a new API access token with a specified expiry.
+Create a new API access token with a specified expiry (max 90 days).
+
+**Blast radius:** minted token claims **Administrator** network rating. Treat as a full operator credential.
 
 **Request Body**:
 ```json
@@ -425,13 +491,16 @@ Create a new API access token with a specified expiry.
   "version": "v1",
   "err": null,
   "data": {
-    "token": string // JWT access token
+    "token": string, // JWT access token
+    "recommended_api_version": string, // pin production clients should send
+    "api_version_min": string,
+    "api_version_max": string
   }
 }
 ```
 
 **Errors**:
-- **400 Bad Request**: Invalid JSON body or expiry date in the past.
+- **400 Bad Request**: Invalid JSON body, expiry in the past, or expiry more than 90 days out.
 - **401 Unauthorized**: Invalid bearer token.
 - **403 Forbidden**: Insufficient permissions (Administrator rating required).
 - **500 Internal Server Error**: Error generating or signing token.
diff --git a/internal/web/api_editor.go b/internal/web/api_editor.go
index 4446e7c..8a000b2 100644
--- a/internal/web/api_editor.go
+++ b/internal/web/api_editor.go
@@ -36,7 +36,7 @@ type editorValidateAIRData struct {
 // Authz is inline I1+ → 403 JSON (never HTML redirect).
 func (s *Server) setupEditorAPIRoutes(parent *gin.RouterGroup) {
 	g := parent.Group("/editor")
-	g.Use(s.jwtBearerMiddleware, s.csrfIfCookieSession)
+	s.useAPIV1Protected(g)
 	g.POST("/validate-apt", s.handleAPIValidateAPT)
 	g.POST("/validate-air", s.handleAPIValidateAIR)
 }
diff --git a/internal/web/api_tokens.go b/internal/web/api_tokens.go
index e6069ba..908793b 100644
--- a/internal/web/api_tokens.go
+++ b/internal/web/api_tokens.go
@@ -70,10 +70,18 @@ func (s *Server) handleCreateNewAPIToken(c *gin.Context) {
 	}
 
 	type ResponseBody struct {
-		Token string `json:"token"`
+		Token                 string `json:"token"`
+		RecommendedAPIVersion string `json:"recommended_api_version"`
+		APIVersionMin         string `json:"api_version_min"`
+		APIVersionMax         string `json:"api_version_max"`
 	}
 
-	resBody := ResponseBody{Token: accessTokenStr}
+	resBody := ResponseBody{
+		Token:                 accessTokenStr,
+		RecommendedAPIVersion: apiMicroMax,
+		APIVersionMin:         apiMicroMin,
+		APIVersionMax:         apiMicroMax,
+	}
 	res := newAPIV1Success(&resBody)
 	writeAPIV1Response(c, http.StatusCreated, &res)
 }
diff --git a/internal/web/api_v1_response.go b/internal/web/api_v1_response.go
index d04d108..fd766f1 100644
--- a/internal/web/api_v1_response.go
+++ b/internal/web/api_v1_response.go
@@ -47,6 +47,9 @@ func bindJSONOrAbort(c *gin.Context, reqBody any) (ok bool) {
 }
 
 func writeAPIV1Response(c *gin.Context, code int, res *APIV1Response) {
+	// Soft / hard version headers when context is set; safe defaults otherwise.
+	setAPIVersionHeaders(c)
+
 	resBody, err := json.Marshal(res)
 	if err != nil {
 		c.Writer.Header().Set("Content-Type", "text/plain")
diff --git a/internal/web/api_version.go b/internal/web/api_version.go
new file mode 100644
index 0000000..c465160
--- /dev/null
+++ b/internal/web/api_version.go
@@ -0,0 +1,287 @@
+package web
+
+import (
+	_ "embed"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"gopkg.in/yaml.v3"
+)
+
+// Package-level API microversion registry (KD-3, KD-5, KD-19).
+// Baseline is the UTC merge date of the versioning foundation PR.
+const (
+	apiMajorVersion = "v1"
+
+	// First supported pin / current max (KD-19: UTC calendar date of PR-1 merge).
+	apiMicroMin = "2026-07-28"
+	apiMicroMax = "2026-07-28"
+
+	headerAPIVersion          = "OpenFSD-API-Version"
+	headerAPIMinVersion       = "OpenFSD-API-Min-Version"
+	headerAPIMaxVersion       = "OpenFSD-API-Max-Version"
+	headerAPIVersionDefaulted = "OpenFSD-API-Version-Defaulted" // "true" if header omitted
+
+	apiVersionContextKey = "api_version"
+)
+
+// knownMicroversions lists every still-supported pin in ascending YYYY-MM-DD order.
+var knownMicroversions = []string{
+	"2026-07-28",
+}
+
+var (
+	errAPIVersionInvalid     = errors.New("invalid OpenFSD-API-Version")
+	errAPIVersionUnsupported = errors.New("unsupported OpenFSD-API-Version")
+
+	reAPIVersionDate  = regexp.MustCompile(`^\d{4}-\d{2}-\d{2}$`)
+	reAPIVersionAlias = regexp.MustCompile(`^1\.(\d{8})$`)
+)
+
+// apiVersionContext holds the resolved microversion for a request.
+type apiVersionContext struct {
+	Requested string // raw header (may be empty)
+	Effective string // normalized pin used for shaping
+	Defaulted bool   // true if header omitted (or empty after trim)
+}
+
+// normalizeAPIVersion converts a client version token into canonical YYYY-MM-DD.
+// raw is the header value after the middleware has established it is non-empty.
+// max is apiMicroMax (used for the "latest" alias).
+// Membership in knownMicroversions is checked separately by the middleware.
+func normalizeAPIVersion(raw, max string) (canonical string, err error) {
+	s := strings.TrimSpace(raw)
+	if s == "" {
+		return "", errAPIVersionInvalid
+	}
+
+	// "latest" (any ASCII case) → max
+	if strings.EqualFold(s, "latest") {
+		if max == "" {
+			return "", errAPIVersionInvalid
+		}
+		return max, nil
+	}
+
+	// Alias: 1.YYYYMMDD → YYYY-MM-DD
+	if m := reAPIVersionAlias.FindStringSubmatch(s); m != nil {
+		digits := m[1]
+		s = digits[0:4] + "-" + digits[4:6] + "-" + digits[6:8]
+	}
+
+	if !reAPIVersionDate.MatchString(s) {
+		return "", errAPIVersionInvalid
+	}
+
+	// Reject impossible calendar dates (e.g. 2026-02-30).
+	if _, parseErr := time.ParseInLocation("2006-01-02", s, time.UTC); parseErr != nil {
+		return "", errAPIVersionInvalid
+	}
+
+	return s, nil
+}
+
+func isKnownMicroversion(canonical string) bool {
+	for _, v := range knownMicroversions {
+		if v == canonical {
+			return true
+		}
+	}
+	return false
+}
+
+// shapeAdapter is one ordered microversion DTO shaper (KD-12).
+// introducedAt is YYYY-MM-DD (or "epoch"); adapters are sorted ascending.
+type shapeAdapter[T any, D any] struct {
+	introducedAt string
+	shape        func(T) D
+}
+
+// shapeFor selects the newest adapter with introducedAt <= effective (lexicographic ISO dates).
+func shapeFor[T any, D any](effective string, adapters []shapeAdapter[T, D], domain T) D {
+	if len(adapters) == 0 {
+		var zero D
+		return zero
+	}
+	for i := len(adapters) - 1; i >= 0; i-- {
+		if adapters[i].introducedAt <= effective {
+			return adapters[i].shape(domain)
+		}
+	}
+	return adapters[0].shape(domain)
+}
+
+// useAPIV1Protected attaches dual-accept auth + CSRF + API microversion middleware.
+// PR-2 will add Bearer actor revalidation here.
+func (s *Server) useAPIV1Protected(g *gin.RouterGroup) {
+	g.Use(
+		s.jwtBearerMiddleware,
+		s.csrfIfCookieSession,
+		s.apiVersionMiddleware,
+	)
+}
+
+// apiVersionMiddleware resolves OpenFSD-API-Version for dual-accept resource groups.
+// Unknown/invalid pins → 400 envelope. Omitted header → max + Defaulted.
+func (s *Server) apiVersionMiddleware(c *gin.Context) {
+	raw := c.GetHeader(headerAPIVersion)
+	trimmed := strings.TrimSpace(raw)
+
+	ctx := apiVersionContext{Requested: raw}
+
+	if trimmed == "" {
+		ctx.Effective = apiMicroMax
+		ctx.Defaulted = true
+		c.Set(apiVersionContextKey, ctx)
+		setAPIVersionHeaders(c)
+		c.Next()
+		return
+	}
+
+	canonical, err := normalizeAPIVersion(trimmed, apiMicroMax)
+	if err != nil {
+		setAPIVersionHeadersExplicit(c, apiMicroMax, true /* still show registry */)
+		res := newAPIV1Failure("invalid OpenFSD-API-Version")
+		writeAPIV1Response(c, http.StatusBadRequest, &res)
+		c.Abort()
+		return
+	}
+
+	if !isKnownMicroversion(canonical) {
+		setAPIVersionHeadersExplicit(c, apiMicroMax, true)
+		msg := fmt.Sprintf("unsupported OpenFSD-API-Version %q; min=%s max=%s",
+			canonical, apiMicroMin, apiMicroMax)
+		res := newAPIV1Failure(msg)
+		writeAPIV1Response(c, http.StatusBadRequest, &res)
+		c.Abort()
+		return
+	}
+
+	ctx.Effective = canonical
+	ctx.Defaulted = false
+	c.Set(apiVersionContextKey, ctx)
+	setAPIVersionHeaders(c)
+	c.Next()
+}
+
+// getAPIVersionContext returns the resolved microversion, if any.
+func getAPIVersionContext(c *gin.Context) (apiVersionContext, bool) {
+	val, ok := c.Get(apiVersionContextKey)
+	if !ok {
+		return apiVersionContext{}, false
+	}
+	ctx, ok := val.(apiVersionContext)
+	return ctx, ok
+}
+
+// effectiveAPIVersion returns the effective pin, or apiMicroMax when unset.
+func effectiveAPIVersion(c *gin.Context) string {
+	if ctx, ok := getAPIVersionContext(c); ok && ctx.Effective != "" {
+		return ctx.Effective
+	}
+	return apiMicroMax
+}
+
+// setAPIVersionHeaders writes version response headers from gin context.
+// Safe no-op-with-soft-defaults when the version context is missing (public routes).
+func setAPIVersionHeaders(c *gin.Context) {
+	if ctx, ok := getAPIVersionContext(c); ok {
+		setAPIVersionHeadersValues(c, ctx.Effective, ctx.Defaulted)
+		return
+	}
+	// Soft observability headers on public / envelope responses without hard pin.
+	setAPIVersionHeadersValues(c, apiMicroMax, false)
+}
+
+// setAPIVersionHeadersExplicit sets registry headers with a chosen effective pin
+// (used when rejecting a bad pin before context is stored).
+func setAPIVersionHeadersExplicit(c *gin.Context, effective string, _ bool) {
+	setAPIVersionHeadersValues(c, effective, false)
+}
+
+func setAPIVersionHeadersValues(c *gin.Context, effective string, defaulted bool) {
+	if effective == "" {
+		effective = apiMicroMax
+	}
+	h := c.Writer.Header()
+	h.Set(headerAPIVersion, effective)
+	h.Set(headerAPIMinVersion, apiMicroMin)
+	h.Set(headerAPIMaxVersion, apiMicroMax)
+	// Caches must vary on the client pin.
+	h.Set("Vary", headerAPIVersion)
+	if defaulted {
+		h.Set(headerAPIVersionDefaulted, "true")
+	}
+}
+
+// discoveryData is the public version-discovery payload (KD-20).
+type discoveryData struct {
+	Major      string   `json:"major"`
+	MinVersion string   `json:"min_version"`
+	MaxVersion string   `json:"max_version"`
+	Versions   []string `json:"versions"`
+	Header     string   `json:"header"`
+	Default    string   `json:"default"`
+	OpenAPI    string   `json:"openapi"`
+}
+
+func newDiscoveryData() discoveryData {
+	versions := make([]string, len(knownMicroversions))
+	copy(versions, knownMicroversions)
+	return discoveryData{
+		Major:      apiMajorVersion,
+		MinVersion: apiMicroMin,
+		MaxVersion: apiMicroMax,
+		Versions:   versions,
+		Header:     headerAPIVersion,
+		Default:    "max",
+		OpenAPI:    "/api/v1/openapi.json",
+	}
+}
+
+// handleAPIDiscovery serves GET /api/v1 and GET /api/v1/versions (public, version-agnostic).
+func (s *Server) handleAPIDiscovery(c *gin.Context) {
+	// Never reject on pin; still emit registry headers for observability.
+	setAPIVersionHeadersValues(c, apiMicroMax, false)
+	res := newAPIV1Success(newDiscoveryData())
+	writeAPIV1Response(c, http.StatusOK, &res)
+}
+
+//go:embed openapi/openapi.v1.yaml
+var openAPIYAML []byte
+
+// handleOpenAPIYAML serves the embedded OpenAPI document as YAML (public, version-agnostic).
+func (s *Server) handleOpenAPIYAML(c *gin.Context) {
+	setAPIVersionHeadersValues(c, apiMicroMax, false)
+	c.Header("Content-Type", "application/yaml; charset=utf-8")
+	c.Writer.WriteHeader(http.StatusOK)
+	_, _ = c.Writer.Write(openAPIYAML)
+}
+
+// handleOpenAPIJSON serves the embedded OpenAPI document converted to JSON.
+func (s *Server) handleOpenAPIJSON(c *gin.Context) {
+	setAPIVersionHeadersValues(c, apiMicroMax, false)
+	body, err := openAPIYAMLToJSON(openAPIYAML)
+	if err != nil {
+		res := newAPIV1Failure("openapi conversion failed")
+		writeAPIV1Response(c, http.StatusInternalServerError, &res)
+		return
+	}
+	c.Header("Content-Type", "application/json; charset=utf-8")
+	c.Writer.WriteHeader(http.StatusOK)
+	_, _ = c.Writer.Write(body)
+}
+
+func openAPIYAMLToJSON(src []byte) ([]byte, error) {
+	var doc any
+	if err := yaml.Unmarshal(src, &doc); err != nil {
+		return nil, err
+	}
+	return json.Marshal(doc)
+}
diff --git a/internal/web/api_version_test.go b/internal/web/api_version_test.go
new file mode 100644
index 0000000..8378c5a
--- /dev/null
+++ b/internal/web/api_version_test.go
@@ -0,0 +1,401 @@
+package web
+
+import (
+	"bytes"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNormalizeAPIVersion(t *testing.T) {
+	const max = "2026-07-28"
+
+	tests := []struct {
+		name    string
+		raw     string
+		want    string
+		wantErr error
+	}{
+		{name: "dashed date", raw: "2026-07-28", want: "2026-07-28"},
+		{name: "latest lower", raw: "latest", want: max},
+		{name: "latest upper", raw: "LATEST", want: max},
+		{name: "latest mixed", raw: "Latest", want: max},
+		{name: "latest padded", raw: "  latest  ", want: max},
+		{name: "alias 1.YYYYMMDD", raw: "1.20260728", want: "2026-07-28"},
+		{name: "alias with spaces", raw: " 1.20260728 ", want: "2026-07-28"},
+		{name: "date padded", raw: " 2026-07-28 ", want: "2026-07-28"},
+
+		// Invalid forms
+		{name: "empty", raw: "", wantErr: errAPIVersionInvalid},
+		{name: "whitespace only", raw: "   ", wantErr: errAPIVersionInvalid},
+		{name: "mixed alias with dashes", raw: "1.2026-07-28", wantErr: errAPIVersionInvalid},
+		{name: "v1 prefix", raw: "v1.2026-07-28", wantErr: errAPIVersionInvalid},
+		{name: "slash date", raw: "2026/07/28", wantErr: errAPIVersionInvalid},
+		{name: "garbage", raw: "not-a-version", wantErr: errAPIVersionInvalid},
+		{name: "partial date", raw: "2026-07", wantErr: errAPIVersionInvalid},
+		{name: "impossible date Feb 30", raw: "2026-02-30", wantErr: errAPIVersionInvalid},
+		{name: "impossible date Apr 31", raw: "2026-04-31", wantErr: errAPIVersionInvalid},
+		{name: "zero month", raw: "2026-00-15", wantErr: errAPIVersionInvalid},
+		{name: "alias bad day", raw: "1.20260230", wantErr: errAPIVersionInvalid},
+		{name: "alias short", raw: "1.2026072", wantErr: errAPIVersionInvalid},
+		{name: "alias long", raw: "1.202607281", wantErr: errAPIVersionInvalid},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got, err := normalizeAPIVersion(tc.raw, max)
+			if tc.wantErr != nil {
+				require.ErrorIs(t, err, tc.wantErr)
+				assert.Empty(t, got)
+				return
+			}
+			require.NoError(t, err)
+			assert.Equal(t, tc.want, got)
+		})
+	}
+}
+
+func TestShapeFor(t *testing.T) {
+	type domain struct{ N int }
+	type dto struct{ Label string }
+
+	adapters := []shapeAdapter[domain, dto]{
+		{introducedAt: "2026-07-28", shape: func(d domain) dto { return dto{Label: "baseline"} }},
+		{introducedAt: "2026-09-01", shape: func(d domain) dto { return dto{Label: "sept"} }},
+		{introducedAt: "2026-11-01", shape: func(d domain) dto { return dto{Label: "nov"} }},
+	}
+
+	// Walk every still-supported pin (only baseline today) + future pins for matrix.
+	assert.Equal(t, "baseline", shapeFor("2026-07-28", adapters, domain{}).Label)
+	assert.Equal(t, "sept", shapeFor("2026-09-01", adapters, domain{}).Label)
+	assert.Equal(t, "sept", shapeFor("2026-10-15", adapters, domain{}).Label)
+	assert.Equal(t, "nov", shapeFor("2026-11-01", adapters, domain{}).Label)
+	assert.Equal(t, "nov", shapeFor("2027-01-01", adapters, domain{}).Label)
+	// Before first adapter → first adapter (defensive).
+	assert.Equal(t, "baseline", shapeFor("2020-01-01", adapters, domain{}).Label)
+
+	for _, pin := range knownMicroversions {
+		got := shapeFor(pin, adapters, domain{})
+		assert.NotEmpty(t, got.Label, "pin %s must resolve", pin)
+	}
+
+	// Empty adapters → zero value.
+	var empty []shapeAdapter[domain, dto]
+	assert.Equal(t, dto{}, shapeFor("2026-07-28", empty, domain{}))
+}
+
+func TestAPIVersionMiddleware_OmitDefaultsMax(t *testing.T) {
+	env := setupTestAPI(t)
+	access, _ := env.login(t, env.admin.CID, env.adminPass)
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/config/load", nil)
+	req.Header.Set("Authorization", "Bearer "+access)
+	w := httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+	assert.Equal(t, apiMicroMax, w.Header().Get(headerAPIVersion))
+	assert.Equal(t, apiMicroMin, w.Header().Get(headerAPIMinVersion))
+	assert.Equal(t, apiMicroMax, w.Header().Get(headerAPIMaxVersion))
+	assert.Equal(t, "true", w.Header().Get(headerAPIVersionDefaulted))
+	assert.Contains(t, w.Header().Get("Vary"), headerAPIVersion)
+}
+
+func TestAPIVersionMiddleware_PinnedKnown(t *testing.T) {
+	env := setupTestAPI(t)
+	access, _ := env.login(t, env.admin.CID, env.adminPass)
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/config/load", nil)
+	req.Header.Set("Authorization", "Bearer "+access)
+	req.Header.Set(headerAPIVersion, "2026-07-28")
+	w := httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+	assert.Equal(t, "2026-07-28", w.Header().Get(headerAPIVersion))
+	assert.Empty(t, w.Header().Get(headerAPIVersionDefaulted))
+}
+
+func TestAPIVersionMiddleware_LatestAlias(t *testing.T) {
+	env := setupTestAPI(t)
+	access, _ := env.login(t, env.admin.CID, env.adminPass)
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/config/load", nil)
+	req.Header.Set("Authorization", "Bearer "+access)
+	req.Header.Set(headerAPIVersion, "LATEST")
+	w := httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+	assert.Equal(t, apiMicroMax, w.Header().Get(headerAPIVersion))
+	assert.Empty(t, w.Header().Get(headerAPIVersionDefaulted))
+}
+
+func TestAPIVersionMiddleware_AliasForm(t *testing.T) {
+	env := setupTestAPI(t)
+	access, _ := env.login(t, env.admin.CID, env.adminPass)
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/config/load", nil)
+	req.Header.Set("Authorization", "Bearer "+access)
+	req.Header.Set(headerAPIVersion, "1.20260728")
+	w := httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+	assert.Equal(t, "2026-07-28", w.Header().Get(headerAPIVersion))
+}
+
+func TestAPIVersionMiddleware_UnknownPin400(t *testing.T) {
+	env := setupTestAPI(t)
+	access, _ := env.login(t, env.admin.CID, env.adminPass)
+
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/config/load", nil)
+	req.Header.Set("Authorization", "Bearer "+access)
+	req.Header.Set(headerAPIVersion, "2020-01-01")
+	w := httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusBadRequest, w.Code, w.Body.String())
+	res := decodeAPIV1(t, w)
+	require.NotNil(t, res.Err)
+	assert.Contains(t, *res.Err, "unsupported OpenFSD-API-Version")
+	assert.Contains(t, *res.Err, "2020-01-01")
+	assert.Equal(t, apiMicroMin, w.Header().Get(headerAPIMinVersion))
+	assert.Equal(t, apiMicroMax, w.Header().Get(headerAPIMaxVersion))
+}
+
+func TestAPIVersionMiddleware_InvalidPin400(t *testing.T) {
+	env := setupTestAPI(t)
+	access, _ := env.login(t, env.admin.CID, env.adminPass)
+
+	for _, pin := range []string{"1.2026-07-28", "not-a-date", "2026-02-30"} {
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/config/load", nil)
+		req.Header.Set("Authorization", "Bearer "+access)
+		req.Header.Set(headerAPIVersion, pin)
+		w := httptest.NewRecorder()
+		env.router.ServeHTTP(w, req)
+
+		require.Equal(t, http.StatusBadRequest, w.Code, "pin=%s body=%s", pin, w.Body.String())
+		res := decodeAPIV1(t, w)
+		require.NotNil(t, res.Err)
+		assert.Equal(t, "invalid OpenFSD-API-Version", *res.Err)
+	}
+}
+
+func TestAPIDiscovery_VersionAgnostic(t *testing.T) {
+	env := setupTestAPI(t)
+
+	paths := []string{"/api/v1", "/api/v1/", "/api/v1/versions"}
+	// Gin may normalize trailing slash — hit both discovery routes + bad pin.
+	for _, path := range []string{"/api/v1", "/api/v1/versions"} {
+		req := httptest.NewRequest(http.MethodGet, path, nil)
+		req.Header.Set(headerAPIVersion, "2020-01-01") // would 400 on resource groups
+		w := httptest.NewRecorder()
+		env.router.ServeHTTP(w, req)
+
+		require.Equal(t, http.StatusOK, w.Code, "path=%s body=%s", path, w.Body.String())
+		res := decodeAPIV1(t, w)
+		require.Nil(t, res.Err)
+		assert.Equal(t, "v1", res.Version)
+
+		// Never 400 for pin on discovery.
+		assert.Equal(t, apiMicroMax, w.Header().Get(headerAPIVersion))
+		assert.Equal(t, apiMicroMin, w.Header().Get(headerAPIMinVersion))
+		assert.Equal(t, apiMicroMax, w.Header().Get(headerAPIMaxVersion))
+		_ = paths
+	}
+}
+
+func TestAPIDiscovery_PayloadGolden(t *testing.T) {
+	env := setupTestAPI(t)
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/versions", nil)
+	w := httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+	require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+	assertGoldenJSON(t, "2026-07-28/discovery.json", w.Body.Bytes())
+}
+
+func TestOpenAPIEndpoints(t *testing.T) {
+	env := setupTestAPI(t)
+
+	// YAML
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/openapi.yaml", nil)
+	req.Header.Set(headerAPIVersion, "bogus") // must not 400
+	w := httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+	require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+	assert.Contains(t, w.Header().Get("Content-Type"), "yaml")
+	assert.Contains(t, w.Body.String(), "openapi:")
+	assert.Contains(t, w.Body.String(), "openfsd")
+
+	// JSON
+	req = httptest.NewRequest(http.MethodGet, "/api/v1/openapi.json", nil)
+	req.Header.Set(headerAPIVersion, "2020-01-01")
+	w = httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+	require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+	assert.Contains(t, w.Header().Get("Content-Type"), "json")
+	var doc map[string]any
+	require.NoError(t, json.Unmarshal(w.Body.Bytes(), &doc))
+	assert.Contains(t, doc, "openapi")
+	assert.Contains(t, doc, "paths")
+}
+
+func TestDataFeed_NoVersionReject(t *testing.T) {
+	env := setupTestAPI(t)
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/data/status.json", nil)
+	req.Header.Set(headerAPIVersion, "2020-01-01")
+	w := httptest.NewRecorder()
+	env.router.ServeHTTP(w, req)
+	require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+}
+
+func TestCreateToken_RecommendedAPIVersionFields(t *testing.T) {
+	env := setupTestAPI(t)
+	adminAccess, _ := env.login(t, env.admin.CID, env.adminPass)
+
+	w := env.doJSON(t, http.MethodPost, "/api/v1/config/createtoken", map[string]any{
+		"expiry_date_time": time.Now().UTC().Add(2 * time.Hour).Format(time.RFC3339),
+	}, adminAccess)
+	require.Equal(t, http.StatusCreated, w.Code, w.Body.String())
+	res := decodeAPIV1(t, w)
+	require.Nil(t, res.Err)
+
+	data, err := json.Marshal(res.Data)
+	require.NoError(t, err)
+	var body struct {
+		Token                 string `json:"token"`
+		RecommendedAPIVersion string `json:"recommended_api_version"`
+		APIVersionMin         string `json:"api_version_min"`
+		APIVersionMax         string `json:"api_version_max"`
+	}
+	require.NoError(t, json.Unmarshal(data, &body))
+	require.NotEmpty(t, body.Token)
+	assert.Equal(t, apiMicroMax, body.RecommendedAPIVersion)
+	assert.Equal(t, apiMicroMin, body.APIVersionMin)
+	assert.Equal(t, apiMicroMax, body.APIVersionMax)
+
+	// Golden with redacted token.
+	var envelope map[string]any
+	require.NoError(t, json.Unmarshal(w.Body.Bytes(), &envelope))
+	dataMap, ok := envelope["data"].(map[string]any)
+	require.True(t, ok)
+	dataMap["token"] = "<redacted>"
+	rewritten, err := json.Marshal(envelope)
+	require.NoError(t, err)
+	assertGoldenJSON(t, "2026-07-28/createtoken_fields.json", rewritten)
+}
+
+func TestAPIV1Goldens_EnvelopedRoutes(t *testing.T) {
+	env := setupTestAPI(t)
+	obsAccess, _ := env.login(t, env.observer.CID, env.observerPass)
+	adminAccess, _ := env.login(t, env.admin.CID, env.adminPass)
+
+	t.Run("error_unauthorized", func(t *testing.T) {
+		w := env.doJSON(t, http.MethodPost, "/api/v1/user/load", map[string]any{"cid": env.observer.CID}, "")
+		require.Equal(t, http.StatusUnauthorized, w.Code)
+		assertGoldenJSON(t, "2026-07-28/error_unauthorized.json", w.Body.Bytes())
+	})
+
+	t.Run("error_forbidden", func(t *testing.T) {
+		w := env.doJSON(t, http.MethodGet, "/api/v1/config/load", nil, obsAccess)
+		require.Equal(t, http.StatusForbidden, w.Code)
+		assertGoldenJSON(t, "2026-07-28/error_forbidden.json", w.Body.Bytes())
+	})
+
+	t.Run("error_invalid_json", func(t *testing.T) {
+		req := httptest.NewRequest(http.MethodPost, "/api/v1/user/load", bytes.NewReader([]byte(`{not-json`)))
+		req.Header.Set("Content-Type", "application/json")
+		req.Header.Set("Authorization", "Bearer "+obsAccess)
+		w := httptest.NewRecorder()
+		env.router.ServeHTTP(w, req)
+		require.Equal(t, http.StatusBadRequest, w.Code, w.Body.String())
+		assertGoldenJSON(t, "2026-07-28/error_invalid_json.json", w.Body.Bytes())
+	})
+
+	t.Run("error_invalid_version", func(t *testing.T) {
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/config/load", nil)
+		req.Header.Set("Authorization", "Bearer "+adminAccess)
+		req.Header.Set(headerAPIVersion, "1.2026-07-28")
+		w := httptest.NewRecorder()
+		env.router.ServeHTTP(w, req)
+		require.Equal(t, http.StatusBadRequest, w.Code)
+		assertGoldenJSON(t, "2026-07-28/error_invalid_version.json", w.Body.Bytes())
+	})
+
+	t.Run("error_unsupported_version", func(t *testing.T) {
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/config/load", nil)
+		req.Header.Set("Authorization", "Bearer "+adminAccess)
+		req.Header.Set(headerAPIVersion, "2020-01-01")
+		w := httptest.NewRecorder()
+		env.router.ServeHTTP(w, req)
+		require.Equal(t, http.StatusBadRequest, w.Code)
+		assertGoldenJSON(t, "2026-07-28/error_unsupported_version.json", w.Body.Bytes())
+	})
+
+	t.Run("config_update_ok", func(t *testing.T) {
+		w := env.doJSON(t, http.MethodPost, "/api/v1/config/update", map[string]any{
+			"key_value_pairs": []map[string]string{
+				{"key": "WELCOME_MESSAGE", "value": "hello golden"},
+			},
+		}, adminAccess)
+		require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+		assertGoldenJSON(t, "2026-07-28/config_update_ok.json", w.Body.Bytes())
+	})
+
+	t.Run("user_load_self", func(t *testing.T) {
+		w := env.doJSON(t, http.MethodPost, "/api/v1/user/load", map[string]any{
+			"cid": env.observer.CID,
+		}, obsAccess)
+		require.Equal(t, http.StatusOK, w.Code, w.Body.String())
+
+		// Rewrite dynamic CID to 0 for golden compare.
+		var envelope map[string]any
+		require.NoError(t, json.Unmarshal(w.Body.Bytes(), &envelope))
+		dataMap, ok := envelope["data"].(map[string]any)
+		require.True(t, ok)
+		dataMap["cid"] = float64(0) // JSON numbers → float64
+		rewritten, err := json.Marshal(envelope)
+		require.NoError(t, err)
+		assertGoldenJSON(t, "2026-07-28/user_load_self.json", rewritten)
+	})
+}
+
+// assertGoldenJSON compares got JSON to a fixture under testdata/api_v1/.
+// Comparison is semantic (via json.Unmarshal + remarshal) so key order is ignored.
+func assertGoldenJSON(t *testing.T, rel string, got []byte) {
+	t.Helper()
+	path := filepath.Join("testdata", "api_v1", filepath.FromSlash(rel))
+	wantBytes, err := os.ReadFile(path)
+	require.NoError(t, err, "read golden %s", path)
+
+	var wantAny, gotAny any
+	require.NoError(t, json.Unmarshal(wantBytes, &wantAny), "parse golden %s", path)
+	require.NoError(t, json.Unmarshal(got, &gotAny), "parse response: %s", string(got))
+
+	wantNorm, err := json.Marshal(wantAny)
+	require.NoError(t, err)
+	gotNorm, err := json.Marshal(gotAny)
+	require.NoError(t, err)
+
+	if !bytes.Equal(wantNorm, gotNorm) {
+		t.Fatalf("golden mismatch for %s\n--- want ---\n%s\n--- got ---\n%s\n",
+			rel, prettyJSON(wantNorm), prettyJSON(gotNorm))
+	}
+}
+
+func prettyJSON(b []byte) string {
+	var buf bytes.Buffer
+	if err := json.Indent(&buf, b, "", "  "); err != nil {
+		return string(b)
+	}
+	return strings.TrimSpace(buf.String())
+}
diff --git a/internal/web/openapi/openapi.v1.yaml b/internal/web/openapi/openapi.v1.yaml
new file mode 100644
index 0000000..99f50e3
--- /dev/null
+++ b/internal/web/openapi/openapi.v1.yaml
@@ -0,0 +1,523 @@
+openapi: 3.0.3
+info:
+  title: openfsd Operator REST API
+  description: |
+    JSON control surface for **operator automation** against an openfsd deployment.
+
+    **Blast radius:** Admin-minted API tokens currently carry Administrator-equivalent
+    network rating claims. Treat tokens as full operator credentials until fine-grained
+    scopes exist. Prefer short TTLs (max 90 days) and rotate via secret reset when needed.
+
+    **Versioning:** URL major is `/api/v1`. Rare breaking changes use the
+    `OpenFSD-API-Version` date microversion header (`YYYY-MM-DD`). Production clients
+    MUST send a supported pin. When omitted, the server defaults to `max_version` and
+    sets `OpenFSD-API-Version-Defaulted: true`. Discovery (`GET /api/v1` and
+    `GET /api/v1/versions`) and OpenAPI are version-agnostic (never reject on pin).
+
+    Envelope for JSON resources: `{ "version": "v1", "err": string|null, "data": … }`.
+    Body `version` is the major only; microversion appears only in response headers.
+  version: "1.0.0"
+  x-openfsd-api-micro-min: "2026-07-28"
+  x-openfsd-api-micro-max: "2026-07-28"
+
+servers:
+  - url: /api/v1
+    description: Relative to the openfsd web listener
+
+tags:
+  - name: Discovery
+    description: Version-agnostic discovery and machine-readable schema
+  - name: Auth
+    description: Password login / refresh (discouraged for automation; mint API tokens instead)
+  - name: User
+    description: User load/create/update (Stable)
+  - name: Config
+    description: Server configuration and API tokens (Stable; admin)
+  - name: FSDConn
+    description: Active FSD connection control (Stable)
+  - name: Editor
+    description: APT/AIR validate (Stable; Instructor1+)
+  - name: Sweatbox
+    description: Read-only PE proxies (raw; outside envelope goldens)
+  - name: Data
+    description: Public data feeds (outside microversion reject)
+
+paths:
+  /:
+    get:
+      tags: [Discovery]
+      summary: API discovery
+      operationId: getDiscovery
+      x-openfsd-stability: stable
+      security: []
+      responses:
+        "200":
+          description: Discovery payload (same as /versions)
+          headers:
+            OpenFSD-API-Version:
+              schema: { type: string }
+            OpenFSD-API-Min-Version:
+              schema: { type: string }
+            OpenFSD-API-Max-Version:
+              schema: { type: string }
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1EnvelopeDiscovery"
+
+  /versions:
+    get:
+      tags: [Discovery]
+      summary: Supported microversions (same payload as GET /)
+      operationId: getVersions
+      x-openfsd-stability: stable
+      security: []
+      responses:
+        "200":
+          description: Discovery payload
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1EnvelopeDiscovery"
+
+  /openapi.json:
+    get:
+      tags: [Discovery]
+      summary: OpenAPI 3 document (JSON)
+      operationId: getOpenAPIJSON
+      x-openfsd-stability: stable
+      security: []
+      responses:
+        "200":
+          description: OpenAPI document
+          content:
+            application/json:
+              schema:
+                type: object
+
+  /openapi.yaml:
+    get:
+      tags: [Discovery]
+      summary: OpenAPI 3 document (YAML source)
+      operationId: getOpenAPIYAML
+      x-openfsd-stability: stable
+      security: []
+      responses:
+        "200":
+          description: OpenAPI YAML
+          content:
+            application/yaml:
+              schema:
+                type: string
+
+  /auth/login:
+    post:
+      tags: [Auth]
+      summary: Password login (not for production automation)
+      operationId: postAuthLogin
+      x-openfsd-stability: stable
+      security: []
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              required: [cid, password]
+              properties:
+                cid: { type: integer, minimum: 1 }
+                password: { type: string }
+                remember_me: { type: boolean }
+      responses:
+        "200":
+          description: Access + refresh tokens
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /auth/refresh:
+    post:
+      tags: [Auth]
+      summary: Refresh access token (not for production automation)
+      operationId: postAuthRefresh
+      x-openfsd-stability: stable
+      security: []
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              required: [refresh_token]
+              properties:
+                refresh_token: { type: string }
+      responses:
+        "200":
+          description: New access token
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /fsd-jwt:
+    post:
+      tags: [Auth]
+      summary: FSD JWT (VATSIM-shaped; outside envelope / microversion reject)
+      operationId: postFsdJwt
+      x-openfsd-stability: stable
+      security: []
+      responses:
+        "200":
+          description: VATSIM-shaped success body
+
+  /user/load:
+    post:
+      tags: [User]
+      summary: Load user by CID
+      operationId: postUserLoad
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              required: [cid]
+              properties:
+                cid: { type: integer, minimum: 1 }
+      responses:
+        "200":
+          description: User record
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /user/update:
+    patch:
+      tags: [User]
+      summary: Update user (Supervisor+)
+      operationId: patchUserUpdate
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      responses:
+        "200":
+          description: Updated user
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /user/create:
+    post:
+      tags: [User]
+      summary: Create user (Supervisor+)
+      operationId: postUserCreate
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      responses:
+        "201":
+          description: Created user
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /config/load:
+    get:
+      tags: [Config]
+      summary: Load editable config keys (Administrator)
+      operationId: getConfigLoad
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      responses:
+        "200":
+          description: Key/value pairs
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /config/update:
+    post:
+      tags: [Config]
+      summary: Update config keys (Administrator)
+      operationId: postConfigUpdate
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      responses:
+        "200":
+          description: Success
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /config/resetsecretkey:
+    post:
+      tags: [Config]
+      summary: Rotate JWT secret (invalidates all tokens)
+      operationId: postConfigResetSecretKey
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      responses:
+        "200":
+          description: Secret rotated
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /config/createtoken:
+    post:
+      tags: [Config]
+      summary: Mint long-lived admin API access token (max 90 days)
+      description: |
+        Returns a Bearer access JWT with Administrator rating claim plus recommended
+        microversion fields. **Operator-automation blast radius:** treat as full admin
+        credential. Production clients should send `OpenFSD-API-Version` equal to
+        `recommended_api_version`.
+      operationId: postConfigCreateToken
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              required: [expiry_date_time]
+              properties:
+                expiry_date_time:
+                  type: string
+                  format: date-time
+      responses:
+        "201":
+          description: Token minted
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1EnvelopeCreateToken"
+
+  /fsdconn/kickuser:
+    post:
+      tags: [FSDConn]
+      summary: Kick active connection by callsign (Supervisor+)
+      operationId: postFsdconnKickuser
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              required: [callsign]
+              properties:
+                callsign: { type: string }
+      responses:
+        "200":
+          description: Kicked
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /editor/validate-apt:
+    post:
+      tags: [Editor]
+      summary: Validate APT text (Instructor1+)
+      operationId: postEditorValidateApt
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              required: [text]
+              properties:
+                text: { type: string }
+      responses:
+        "200":
+          description: Soft validation result
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /editor/validate-air:
+    post:
+      tags: [Editor]
+      summary: Validate AIR text (Instructor1+)
+      operationId: postEditorValidateAir
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: object
+              required: [text]
+              properties:
+                text: { type: string }
+      responses:
+        "200":
+          description: Soft validation result
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/APIV1Envelope"
+
+  /sweatbox/state:
+    get:
+      tags: [Sweatbox]
+      summary: Raw FSD sweatbox state (PE poll; non-envelope)
+      operationId: getSweatboxState
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      responses:
+        "200":
+          description: Raw FSD JSON body
+
+  /sweatbox/ops:
+    get:
+      tags: [Sweatbox]
+      summary: Raw FSD sweatbox ops (PE poll; non-envelope)
+      operationId: getSweatboxOps
+      x-openfsd-stability: stable
+      security:
+        - bearerAuth: []
+        - cookieAuth: []
+      parameters:
+        - $ref: "#/components/parameters/OpenFSDAPIVersion"
+      responses:
+        "200":
+          description: Raw FSD JSON body
+
+components:
+  securitySchemes:
+    bearerAuth:
+      type: http
+      scheme: bearer
+      bearerFormat: JWT
+      description: Access JWT (API token or short-lived access). No CSRF required.
+    cookieAuth:
+      type: apiKey
+      in: cookie
+      name: openfsd_session
+      description: First-party session cookie; mutations require CSRF synchronizer.
+
+  parameters:
+    OpenFSDAPIVersion:
+      name: OpenFSD-API-Version
+      in: header
+      required: false
+      description: |
+        Date microversion pin (`YYYY-MM-DD` or `1.YYYYMMDD` or `latest`).
+        Production clients MUST send a supported pin. Omitted → max + Defaulted header.
+      schema:
+        type: string
+        example: "2026-07-28"
+
+  schemas:
+    APIV1Envelope:
+      type: object
+      required: [version, err, data]
+      properties:
+        version:
+          type: string
+          enum: [v1]
+          description: URL major only; microversion is header-only
+        err:
+          type: string
+          nullable: true
+        data:
+          nullable: true
+
+    DiscoveryData:
+      type: object
+      required: [major, min_version, max_version, versions, header, default, openapi]
+      properties:
+        major: { type: string, example: v1 }
+        min_version: { type: string, example: "2026-07-28" }
+        max_version: { type: string, example: "2026-07-28" }
+        versions:
+          type: array
+          items: { type: string }
+        header: { type: string, example: OpenFSD-API-Version }
+        default: { type: string, example: max }
+        openapi: { type: string, example: /api/v1/openapi.json }
+
+    APIV1EnvelopeDiscovery:
+      allOf:
+        - $ref: "#/components/schemas/APIV1Envelope"
+        - type: object
+          properties:
+            data:
+              $ref: "#/components/schemas/DiscoveryData"
+
+    CreateTokenData:
+      type: object
+      required: [token, recommended_api_version, api_version_min, api_version_max]
+      properties:
+        token: { type: string }
+        recommended_api_version: { type: string, example: "2026-07-28" }
+        api_version_min: { type: string, example: "2026-07-28" }
+        api_version_max: { type: string, example: "2026-07-28" }
+
+    APIV1EnvelopeCreateToken:
+      allOf:
+        - $ref: "#/components/schemas/APIV1Envelope"
+        - type: object
+          properties:
+            data:
+              $ref: "#/components/schemas/CreateTokenData"
diff --git a/internal/web/routes.go b/internal/web/routes.go
index bda746f..f63d295 100644
--- a/internal/web/routes.go
+++ b/internal/web/routes.go
@@ -33,11 +33,20 @@ func (s *Server) setupRoutes() (*gin.Engine, error) {
 
 	// API groups — dual-accept Bearer | session cookie; CSRF when cookie-authenticated.
 	apiV1Group := e.Group("/api/v1")
-	apiV1Group.POST("/fsd-jwt", s.getFsdJwt)
-	s.setupAuthRoutes(apiV1Group)
+
+	// Version-agnostic public discovery + OpenAPI (no JWT, no version-reject).
+	apiV1Group.GET("", s.handleAPIDiscovery)
+	apiV1Group.GET("/versions", s.handleAPIDiscovery)
+	apiV1Group.GET("/openapi.json", s.handleOpenAPIJSON)
+	apiV1Group.GET("/openapi.yaml", s.handleOpenAPIYAML)
+
+	apiV1Group.POST("/fsd-jwt", s.getFsdJwt) // outside microversion reject
+	s.setupAuthRoutes(apiV1Group)            // login/refresh: soft version headers only
+	s.setupDataRoutes(apiV1Group)            // never version-reject
+
+	// Dual-accept JSON resource groups (jwt + csrf + apiVersion).
 	s.setupUserRoutes(apiV1Group)
 	s.setupConfigRoutes(apiV1Group)
-	s.setupDataRoutes(apiV1Group)
 	s.setupFsdConnRoutes(apiV1Group)
 	s.setupSweatboxAPIRoutes(apiV1Group)
 	s.setupEditorAPIRoutes(apiV1Group)
@@ -63,7 +72,7 @@ func (s *Server) setupAuthRoutes(parent *gin.RouterGroup) {
 
 func (s *Server) setupUserRoutes(parent *gin.RouterGroup) {
 	usersGroup := parent.Group("/user")
-	usersGroup.Use(s.jwtBearerMiddleware, s.csrfIfCookieSession)
+	s.useAPIV1Protected(usersGroup)
 	usersGroup.POST("/load", s.getUserByCID)
 	usersGroup.PATCH("/update", s.updateUser)
 	usersGroup.POST("/create", s.createUser)
@@ -71,7 +80,7 @@ func (s *Server) setupUserRoutes(parent *gin.RouterGroup) {
 
 func (s *Server) setupConfigRoutes(parent *gin.RouterGroup) {
 	configGroup := parent.Group("/config")
-	configGroup.Use(s.jwtBearerMiddleware, s.csrfIfCookieSession)
+	s.useAPIV1Protected(configGroup)
 	configGroup.GET("/load", s.handleGetConfig)
 	configGroup.POST("/update", s.handleUpdateConfig)
 	configGroup.POST("/resetsecretkey", s.handleResetSecretKey)
@@ -80,15 +89,16 @@ func (s *Server) setupConfigRoutes(parent *gin.RouterGroup) {
 
 func (s *Server) setupFsdConnRoutes(parent *gin.RouterGroup) {
 	fsdConnGroup := parent.Group("/fsdconn")
-	fsdConnGroup.Use(s.jwtBearerMiddleware, s.csrfIfCookieSession)
+	s.useAPIV1Protected(fsdConnGroup)
 	fsdConnGroup.POST("/kickuser", s.handleKickActiveConnection)
 }
 
 // setupSweatboxAPIRoutes mounts read-only PE proxies under /api/v1/sweatbox.
 // Mutations stay on HTML form POSTs (CSRF + PRG) — not on this JSON surface.
+// Raw GET bodies are outside envelope goldens; microversion middleware still applies.
 func (s *Server) setupSweatboxAPIRoutes(parent *gin.RouterGroup) {
 	g := parent.Group("/sweatbox")
-	g.Use(s.jwtBearerMiddleware, s.csrfIfCookieSession)
+	s.useAPIV1Protected(g)
 	g.GET("/state", s.handleAPISweatboxState)
 	g.GET("/ops", s.handleAPISweatboxOps)
 }
diff --git a/internal/web/testdata/api_v1/2026-07-28/config_update_ok.json b/internal/web/testdata/api_v1/2026-07-28/config_update_ok.json
new file mode 100644
index 0000000..f5e0090
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/config_update_ok.json
@@ -0,0 +1,5 @@
+{
+  "version": "v1",
+  "err": null,
+  "data": null
+}
diff --git a/internal/web/testdata/api_v1/2026-07-28/createtoken_fields.json b/internal/web/testdata/api_v1/2026-07-28/createtoken_fields.json
new file mode 100644
index 0000000..3339d44
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/createtoken_fields.json
@@ -0,0 +1,10 @@
+{
+  "version": "v1",
+  "err": null,
+  "data": {
+    "token": "<redacted>",
+    "recommended_api_version": "2026-07-28",
+    "api_version_min": "2026-07-28",
+    "api_version_max": "2026-07-28"
+  }
+}
diff --git a/internal/web/testdata/api_v1/2026-07-28/discovery.json b/internal/web/testdata/api_v1/2026-07-28/discovery.json
new file mode 100644
index 0000000..385b697
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/discovery.json
@@ -0,0 +1,13 @@
+{
+  "version": "v1",
+  "err": null,
+  "data": {
+    "major": "v1",
+    "min_version": "2026-07-28",
+    "max_version": "2026-07-28",
+    "versions": ["2026-07-28"],
+    "header": "OpenFSD-API-Version",
+    "default": "max",
+    "openapi": "/api/v1/openapi.json"
+  }
+}
diff --git a/internal/web/testdata/api_v1/2026-07-28/error_forbidden.json b/internal/web/testdata/api_v1/2026-07-28/error_forbidden.json
new file mode 100644
index 0000000..44064df
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/error_forbidden.json
@@ -0,0 +1,5 @@
+{
+  "version": "v1",
+  "err": "forbidden",
+  "data": null
+}
diff --git a/internal/web/testdata/api_v1/2026-07-28/error_invalid_json.json b/internal/web/testdata/api_v1/2026-07-28/error_invalid_json.json
new file mode 100644
index 0000000..cf355a5
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/error_invalid_json.json
@@ -0,0 +1,5 @@
+{
+  "version": "v1",
+  "err": "invalid JSON body",
+  "data": null
+}
diff --git a/internal/web/testdata/api_v1/2026-07-28/error_invalid_version.json b/internal/web/testdata/api_v1/2026-07-28/error_invalid_version.json
new file mode 100644
index 0000000..baba194
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/error_invalid_version.json
@@ -0,0 +1,5 @@
+{
+  "version": "v1",
+  "err": "invalid OpenFSD-API-Version",
+  "data": null
+}
diff --git a/internal/web/testdata/api_v1/2026-07-28/error_unauthorized.json b/internal/web/testdata/api_v1/2026-07-28/error_unauthorized.json
new file mode 100644
index 0000000..22a2a62
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/error_unauthorized.json
@@ -0,0 +1,5 @@
+{
+  "version": "v1",
+  "err": "unauthorized",
+  "data": null
+}
diff --git a/internal/web/testdata/api_v1/2026-07-28/error_unsupported_version.json b/internal/web/testdata/api_v1/2026-07-28/error_unsupported_version.json
new file mode 100644
index 0000000..74a6a3a
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/error_unsupported_version.json
@@ -0,0 +1,5 @@
+{
+  "version": "v1",
+  "err": "unsupported OpenFSD-API-Version \"2020-01-01\"; min=2026-07-28 max=2026-07-28",
+  "data": null
+}
diff --git a/internal/web/testdata/api_v1/2026-07-28/user_load_self.json b/internal/web/testdata/api_v1/2026-07-28/user_load_self.json
new file mode 100644
index 0000000..7b34853
--- /dev/null
+++ b/internal/web/testdata/api_v1/2026-07-28/user_load_self.json
@@ -0,0 +1,11 @@
+{
+  "version": "v1",
+  "err": null,
+  "data": {
+    "cid": 0,
+    "first_name": "Obs",
+    "last_name": "Server",
+    "network_rating": 1,
+    "pilot_rating": 0
+  }
+}