diff --git a/CHANGELOG.md b/CHANGELOG.md
index e2548af8..16a33b0a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,13 @@
 
 # Changelog
 
+## Sprint 48 Backend API contract audit (2026-06-17)
+
+- Added `scripts/audit_api_contracts.py` to compare the active FastAPI route surface with `docs/API_CONTRACTS.md`.
+- Added the API contract audit to the readiness gate so undocumented routes and stale documented routes fail release checks.
+- Corrected API contract drift for area detail/update, vector stats, dataset content and future analysis/YOLO export placeholders.
+- Added regression tests for the contract audit and readiness integration.
+
 ## Sprint 47 Workbench interaction smoke (2026-06-17)
 
 - Added stable `data-testid` anchors to the existing project, area, map, dataset, QA/QC and export controls for browser regression checks.
diff --git a/backend/tests/test_sprint48_api_contract_audit.py b/backend/tests/test_sprint48_api_contract_audit.py
new file mode 100644
index 00000000..850cc083
--- /dev/null
+++ b/backend/tests/test_sprint48_api_contract_audit.py
@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[2]
+
+
+def test_readiness_gate_runs_api_contract_audit() -> None:
+    script = ROOT / "scripts" / "run_readiness_check.sh"
+    content = script.read_text(encoding="utf-8")
+
+    assert "scripts/audit_api_contracts.py" in content
+
+
+def test_api_contract_audit_checks_openapi_against_docs() -> None:
+    script = ROOT / "scripts" / "audit_api_contracts.py"
+    content = script.read_text(encoding="utf-8")
+
+    assert "create_app" in content
+    assert "docs/API_CONTRACTS.md" in content
+    assert "Missing documented API route" in content
+    assert "Documented API route is not implemented" in content
+    assert "Allowed non-envelope endpoint is not implemented" in content
+    assert "/api/v1/exports/{export_id}/download" in content
+
+
+def test_api_contract_docs_include_current_implemented_route_surface() -> None:
+    docs = (ROOT / "docs" / "API_CONTRACTS.md").read_text(encoding="utf-8")
+
+    assert 'GET `/api/v1/projects/{project_id}/areas/{area_id}`' in docs
+    assert 'PATCH `/api/v1/projects/{project_id}/areas/{area_id}`' in docs
+    assert 'GET `/api/v1/projects/{project_id}/datasets/{dataset_id}/vector/stats`' in docs
+    assert 'GET `/api/v1/projects/{project_id}/datasets/{dataset_id}/content`' in docs
+    assert 'POST `/api/v1/projects/{project_id}/datasets/{dataset_id}/vector/stats`' not in docs
diff --git a/docs/API_CONTRACTS.md b/docs/API_CONTRACTS.md
index 4639599d..bce7159c 100644
--- a/docs/API_CONTRACTS.md
+++ b/docs/API_CONTRACTS.md
@@ -161,6 +161,16 @@ Backend responsibilities:
 - Calculate area in square meters using projected CRS.
 - Store bbox.
 
+### GET `/api/v1/projects/{project_id}/areas/{area_id}`
+
+Returns one project area. The payload uses the same `AreaRead` shape as the
+area list endpoint and includes persisted GeoJSON geometry for map display.
+
+### PATCH `/api/v1/projects/{project_id}/areas/{area_id}`
+
+Updates the area name and/or geometry. Geometry updates follow the same
+validation, repair and metric-calculation rules as area creation.
+
 ## Datasets
 
 ### POST `/api/v1/projects/{project_id}/datasets/upload`
@@ -339,7 +349,7 @@ Apply buffer distance to vector features.
 
 Intersect source vector dataset with another vector dataset.
 
-### POST `/api/v1/projects/{project_id}/datasets/{dataset_id}/vector/stats`
+### GET `/api/v1/projects/{project_id}/datasets/{dataset_id}/vector/stats`
 
 Return vector stats (feature counts and geometry summary).
 
@@ -347,6 +357,12 @@ Return vector stats (feature counts and geometry summary).
 
 Return vector bounds and feature count.
 
+### GET `/api/v1/projects/{project_id}/datasets/{dataset_id}/content`
+
+Returns stored vector dataset content through the canonical API envelope.
+Vector content is returned as GeoJSON/JSON payload data. Raster content is not
+served through this endpoint.
+
 ## Jobs
 
 ### POST `/api/v1/projects/{project_id}/jobs`
@@ -670,11 +686,12 @@ Response persists a `quality_check` and `metrics` rows through the existing QA/Q
 
 If the reference dataset has no persisted vector features, the endpoint returns `REFERENCE_FEATURES_NOT_FOUND`. It does not calculate fake QA metrics.
 
-### POST `/api/v1/analysis/building-stats`
+#### Future analysis route: `/api/v1/analysis/building-stats`
 
-Input: area + vector building layer.
+Not implemented in the active API surface. Future input is expected to combine
+an area with a vector building layer.
 
-### POST `/api/v1/analysis/object-detection`
+#### Future analysis route: `/api/v1/analysis/object-detection`
 
 Request:
 
@@ -693,7 +710,7 @@ Request:
 
 Response: `AnalysisRunRead`.
 
-### POST `/api/v1/analysis/segmentation`
+#### Future analysis route: `/api/v1/analysis/segmentation`
 
 Same pattern as object detection, but output includes masks and polygonized geometries.
 
@@ -1027,7 +1044,7 @@ intentionally does not use the JSON envelope because it is a browser/file-downlo
 path; callers that need canonical API JSON should use `/content` for JSON/GeoJSON
 artifacts.
 
-### POST `/api/v1/exports/yolo`
+#### Future export route: `/api/v1/exports/yolo`
 
 Export annotations/detections to YOLO format.
 
diff --git a/docs/CODEX_EXECUTION_LOG.md b/docs/CODEX_EXECUTION_LOG.md
index 408b6162..6886904b 100644
--- a/docs/CODEX_EXECUTION_LOG.md
+++ b/docs/CODEX_EXECUTION_LOG.md
@@ -1,3 +1,38 @@
+## Sprint 48 Backend API contract audit (2026-06-17)
+
+Changed:
+- Added `scripts/audit_api_contracts.py` to import the FastAPI app, enumerate the implemented `GET`/`POST`/`PATCH`/`DELETE` route surface and compare it with active `### METHOD route` headings in `docs/API_CONTRACTS.md`.
+- Added the API contract audit to `scripts/run_readiness_check.sh`.
+- Corrected contract drift in `docs/API_CONTRACTS.md`:
+  - documented `GET/PATCH /api/v1/projects/{project_id}/areas/{area_id}`;
+  - corrected vector stats from `POST` to implemented `GET`;
+  - documented `GET /api/v1/projects/{project_id}/datasets/{dataset_id}/content`;
+  - changed non-implemented building-stats, legacy analysis object-detection/segmentation and YOLO export entries from active route headings to future-route notes.
+- Added `backend/tests/test_sprint48_api_contract_audit.py`.
+- Updated `scripts/README.md`, `docs/TODO.md` and `CHANGELOG.md`.
+
+Validation:
+- RED: `cd backend && python -m pytest tests/test_sprint48_api_contract_audit.py -q` failed before implementation because the audit script, readiness integration and route docs were missing.
+- RED: `python scripts/audit_api_contracts.py` reported missing docs for 4 implemented routes and 5 stale documented routes.
+- `python scripts/audit_api_contracts.py` passed: 76 implemented routes matched docs and 2 explicit non-envelope endpoints were tracked.
+- `cd backend && python -m pytest tests/test_sprint48_api_contract_audit.py tests/test_readiness_gate.py -q` passed: 12 tests.
+- `python -m py_compile scripts/audit_api_contracts.py` passed.
+- `python -m compileall backend/app` passed.
+- `cd backend && python -m pytest -W error::DeprecationWarning` passed: 201 tests.
+- `bash scripts/run_readiness_check.sh` passed and included `API contract audit OK`.
+- `cd frontend && npm run typecheck` passed.
+- `cd frontend && npm run build` passed.
+- `cd backend && python -m alembic heads` passed: `202606120900 (head)`.
+- `cd backend && python -m alembic upgrade head --sql` passed.
+- `bash -n scripts/live_migration_smoke.sh` passed.
+
+Limitations:
+- This pass audits route documentation presence, implemented/stale route drift and explicit non-envelope exceptions. It does not yet exercise every error path response body at runtime.
+- No API behavior, migrations, provider fetching, AI behavior or product capabilities changed.
+
+Next recommended pass:
+- Add an error-envelope runtime audit for representative invalid/missing-resource paths across projects, datasets, providers, detection, segmentation, QA and exports.
+
 ## Sprint 47 Workbench interaction smoke (2026-06-17)
 
 Changed:
diff --git a/docs/TODO.md b/docs/TODO.md
index be662bca..15182b69 100644
--- a/docs/TODO.md
+++ b/docs/TODO.md
@@ -43,6 +43,7 @@ This file now starts with the current implementation status. Older preparation/b
 - [x] Dry-run-first demo export artifact cleanup tooling.
 - [x] Browser-facing default workbench state smoke for the offline demo project.
 - [x] Browser-facing workbench interaction backing-state smoke and stable UI test anchors.
+- [x] Backend API contract audit comparing implemented FastAPI routes with `docs/API_CONTRACTS.md`.
 - [x] Live Docker/PostGIS validation on Tower/Unraid.
 - [x] Real YOLO compatibility smoke with optional AI extras and local model file.
 - [x] Detection and segmentation workflow hook extraction beyond Sprint 10.
@@ -58,7 +59,7 @@ This file now starts with the current implementation status. Older preparation/b
 - [x] Demo workflow orchestration hook decomposition.
 - [x] Final `App.tsx` import/encoding cleanup and size audit.
 - [x] Optional final bootstrap-effect extraction.
-- [ ] Decide next V1 stabilization focus: browser screenshot artifact automation, backend service contract audit, or golden dataset expansion.
+- [ ] Decide next V1 stabilization focus: browser screenshot artifact automation, backend error-envelope audit, or golden dataset expansion.
 
 ## Sprint 8 status
 
diff --git a/scripts/README.md b/scripts/README.md
index d5423d6e..42f29b79 100644
--- a/scripts/README.md
+++ b/scripts/README.md
@@ -4,6 +4,17 @@ Setup-, import-, demo- en maintenance-scripts voor GeoIntel.
 
 ## Runtime verification
 
+Audit the active backend route surface against `docs/API_CONTRACTS.md`:
+
+```bash
+python scripts/audit_api_contracts.py
+```
+
+The audit imports the FastAPI app, compares implemented `GET`/`POST`/`PATCH`/
+`DELETE` routes with active API contract headings and tracks the explicit
+non-envelope exceptions (`/health` and export downloads). It fails when a route
+exists without docs or when docs claim an endpoint that is not implemented.
+
 Verify the browser-facing Docker/LAN runtime:
 
 ```bash
diff --git a/scripts/audit_api_contracts.py b/scripts/audit_api_contracts.py
new file mode 100644
index 00000000..6db3efae
--- /dev/null
+++ b/scripts/audit_api_contracts.py
@@ -0,0 +1,73 @@
+from __future__ import annotations
+
+import re
+import sys
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+BACKEND = ROOT / "backend"
+DOCS = ROOT / "docs" / "API_CONTRACTS.md"  # docs/API_CONTRACTS.md
+
+ALLOWED_NON_ENVELOPE_ENDPOINTS = {
+    ("GET", "/health"),
+    ("GET", "/api/v1/exports/{export_id}/download"),
+}
+
+IGNORED_OPENAPI_PATHS = {
+    "/openapi.json",
+    "/docs",
+    "/docs/oauth2-redirect",
+    "/redoc",
+}
+
+
+def _load_app_routes() -> set[tuple[str, str]]:
+    sys.path.insert(0, str(BACKEND))
+    from app.main import create_app
+
+    app = create_app()
+    routes: set[tuple[str, str]] = set()
+    for route in app.routes:
+        path = getattr(route, "path", None)
+        methods = getattr(route, "methods", set())
+        if not path or path in IGNORED_OPENAPI_PATHS:
+            continue
+        for method in sorted(methods - {"HEAD", "OPTIONS"}):
+            routes.add((method, path))
+    return routes
+
+
+def _load_documented_routes() -> set[tuple[str, str]]:
+    docs = DOCS.read_text(encoding="utf-8")
+    return set(re.findall(r"###\s+(GET|POST|PATCH|DELETE)\s+`([^`]+)`", docs))
+
+
+def main() -> None:
+    implemented_routes = _load_app_routes()
+    documented_routes = _load_documented_routes()
+
+    missing_docs = sorted(implemented_routes - documented_routes)
+    stale_docs = sorted(documented_routes - implemented_routes)
+    missing_non_envelope = sorted(ALLOWED_NON_ENVELOPE_ENDPOINTS - implemented_routes)
+
+    errors: list[str] = []
+    for method, path in missing_docs:
+        errors.append(f"Missing documented API route: {method} {path}")
+    for method, path in stale_docs:
+        errors.append(f"Documented API route is not implemented: {method} {path}")
+    for method, path in missing_non_envelope:
+        errors.append(f"Allowed non-envelope endpoint is not implemented: {method} {path}")
+
+    if errors:
+        raise SystemExit("\n".join(errors))
+
+    print(
+        "API contract audit OK: "
+        f"{len(implemented_routes)} implemented routes match docs; "
+        f"{len(ALLOWED_NON_ENVELOPE_ENDPOINTS)} explicit non-envelope endpoints tracked."
+    )
+
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/run_readiness_check.sh b/scripts/run_readiness_check.sh
index 9d62901d..53bd7191 100755
--- a/scripts/run_readiness_check.sh
+++ b/scripts/run_readiness_check.sh
@@ -32,6 +32,7 @@ bash scripts/check_repo_structure.sh
 ${PYTHON_BIN} scripts/smoke_docs.py
 ${PYTHON_BIN} scripts/validate_fixtures.py
 ${PYTHON_BIN} scripts/smoke_contracts.py
+${PYTHON_BIN} scripts/audit_api_contracts.py
 ${PYTHON_BIN} scripts/preimplementation_audit.py
 ${PYTHON_BIN} scripts/validate_m13_codex_assets.py
 ${PYTHON_BIN} scripts/validate_m14_launch_assets.py