diff --git a/.gitea/workflows/release.yml b/.gitea/workflows/release.yml
index 875dd85..3aec54d 100644
--- a/.gitea/workflows/release.yml
+++ b/.gitea/workflows/release.yml
@@ -63,3 +63,25 @@ jobs:
             --data @release.json \
             "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases" \
             > /dev/null && echo "release $TAG published"
+
+  # Operations QA (issue #90): the pre-approval gate. A human pushes the
+  # prod-vX.Y.Z tag only after BOTH jobs of this release run are green.
+  ops-qa:
+    name: Release-candidate operations QA
+    needs: build-release
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Log in to the Gitea registry
+        run: printf '%s' "${{ secrets.REGISTRY_TOKEN }}" | tr -d '[:space:]' | docker login gitea.101010.cloud -u fable-5 --password-stdin
+
+      - name: Run update simulation, degraded readiness, and backup roundtrip
+        run: |
+          PREV=$(git tag --list 'v*.*.*' --sort=-v:refname | grep -vx "$GITHUB_REF_NAME" | head -n1 || true)
+          NEXT_TAG=$GITHUB_REF_NAME PREV_TAG=$PREV IMAGE_BASE=$IMAGE_BASE \
+            sh deploy/release-qa.sh
diff --git a/deploy/release-qa.sh b/deploy/release-qa.sh
new file mode 100755
index 0000000..a73367b
--- /dev/null
+++ b/deploy/release-qa.sh
@@ -0,0 +1,177 @@
+#!/usr/bin/env sh
+# Release-candidate operations QA (issue #90): the automated proof, run on
+# every release BEFORE the manual prod gate (release.yml job "ops-qa"), that
+# the operational promises hold for exactly the images a human is about to
+# approve:
+#
+#   1. UPDATE SIMULATION  — boot the PREVIOUS release with pre-seeded fixture
+#      content, swap the api to the CANDIDATE against the same database:
+#      migrations apply automatically, readiness is green, the content
+#      survives. Future migrations extend `seed_fixture`/`assert_fixture`
+#      below with their own fixtures — that pair IS the update-fixture
+#      contract (one write on N-1, one read on N).
+#   2. BACKUP/RESTORE ROUNDTRIP — the candidate's backup sidecar dumps the
+#      stack, the set restores into a second, empty database, and the
+#      candidate api serves the content from it. Distinct from the monthly
+#      drill (#87): this runs per release candidate, against candidate
+#      images, never against stage data.
+#   3. DEGRADED READYZ — without converter/renderer sidecars and before the
+#      first backup, readyz must answer 200 with `degraded` and warn-level
+#      checks (never 503) — the #85 semantics, proven on the candidate.
+#
+# Environment:
+#   NEXT_TAG   the candidate release tag (required), e.g. v0.1.2
+#   PREV_TAG   the previous release (empty skips the update simulation)
+#   IMAGE_BASE default gitea.101010.cloud/stwaidele/dorfteich
+set -eu
+
+NEXT_TAG="${NEXT_TAG:?set NEXT_TAG}"
+PREV_TAG="${PREV_TAG:-}"
+IMAGE_BASE="${IMAGE_BASE:-gitea.101010.cloud/stwaidele/dorfteich}"
+P="dorfteich-rqa-$(date +%s)-$$"
+NET="$P-net"
+PGPASS="rqa-$(date +%s)"
+ADMIN_PASS="release qa admin pass 1"
+SESSION=""
+
+log() { echo "release-qa: $*"; }
+fail() { echo "release-qa: FAILED — $*" >&2; exit 1; }
+
+cleanup() {
+  log "tearing down $P"
+  docker rm -f "$P-db" "$P-db2" "$P-api" >/dev/null 2>&1 || true
+  docker volume rm -f "$P-backups" "$P-uploads" "$P-plugins" >/dev/null 2>&1 || true
+  docker network rm "$NET" >/dev/null 2>&1 || true
+}
+trap cleanup EXIT
+
+# No cookie file: the CI job talks to the HOST docker daemon, so bind
+# mounts would resolve host paths — the session travels as a header instead.
+api_curl() { # api_curl <method> <path> [json-body]
+  METHOD=$1; APIPATH=$2; BODY=${3:-}
+  docker run --rm --network "$NET" curlimages/curl:8.10.1 \
+    -s ${SESSION:+-H "Cookie: $SESSION"} -X "$METHOD" \
+    ${BODY:+-H 'Content-Type: application/json' --data "$BODY"} \
+    "http://$P-api:3000/api/v1$APIPATH"
+}
+
+start_api() { # start_api <tag>
+  docker rm -f "$P-api" >/dev/null 2>&1 || true
+  docker run -d --name "$P-api" --network "$NET" \
+    -e DATABASE_URL="$1" \
+    -e SETUP_ADMIN_USERNAME=qa-admin -e SETUP_ADMIN_EMAIL=qa-admin@example.org \
+    -e SETUP_ADMIN_PASSWORD="$ADMIN_PASS" \
+    -v "$P-uploads":/data/uploads -v "$P-plugins":/data/plugins -v "$P-backups":/data/backups:ro \
+    "$IMAGE_BASE-api:$2" >/dev/null
+  for _ in $(seq 1 45); do
+    READY=$(docker run --rm --network "$NET" curlimages/curl:8.10.1 -s "http://$P-api:3000/api/v1/readyz" || true)
+    case "$READY" in *'"database","status":"ok"'*) return 0 ;; esac
+    sleep 2
+  done
+  docker logs "$P-api" | tail -20
+  fail "api ($2) never became ready"
+}
+
+login() {
+  RAW=$(docker run --rm --network "$NET" curlimages/curl:8.10.1 \
+    -si -X POST -H 'Content-Type: application/json' \
+    --data '{"usernameOrEmail":"qa-admin","password":"release qa admin pass 1"}' \
+    "http://$P-api:3000/api/v1/auth/login")
+  SESSION=$(printf '%s' "$RAW" | tr -d '\r' | grep -i '^set-cookie: dt_session=' | head -1 | sed 's/^[Ss]et-[Cc]ookie: //; s/;.*//')
+  [ -n "$SESSION" ] || fail "login failed: $(printf '%s' "$RAW" | tail -1)"
+}
+
+seed_fixture() {
+  # A fresh instance defaults additional_ponds to 0 — the preseeded Site
+  # Admin lifts their own quota through the real admin API first.
+  ME=$(api_curl GET /auth/me)
+  MY_ID=$(echo "$ME" | grep -o '"id":"[^"]*"' | head -1 | cut -d'"' -f4)
+  [ -n "$MY_ID" ] || fail "could not resolve the qa-admin id: $ME"
+  QUOTA=$(api_curl PUT "/admin/quotas/user/$MY_ID/additional_ponds" '{"value":5}')
+  case "$QUOTA" in *'"lines"'*|*additional_ponds*) ;; *) fail "quota override failed: $QUOTA" ;; esac
+  POND=$(api_curl POST /ponds '{"name":"Release QA"}')
+  POND_ID=$(echo "$POND" | grep -o '"id":"[^"]*"' | head -1 | cut -d'"' -f4)
+  [ -n "$POND_ID" ] || fail "pond creation failed: $POND"
+  PAGE=$(api_curl POST "/ponds/$POND_ID/pages" '{"title":"Update fixture page"}')
+  PAGE_ID=$(echo "$PAGE" | grep -o '"id":"[^"]*"' | head -1 | cut -d'"' -f4)
+  [ -n "$PAGE_ID" ] || fail "page creation failed: $PAGE"
+  log "fixture seeded on $1 (pond $POND_ID, page $PAGE_ID)"
+}
+
+assert_fixture() {
+  RES=$(api_curl GET "/pages/$PAGE_ID/comments")
+  case "$RES" in *'"threads"'*) ;; *) fail "fixture page unreadable on $1: $RES" ;; esac
+  log "fixture content intact on $1"
+}
+
+docker network create "$NET" >/dev/null
+docker volume create "$P-backups" >/dev/null
+docker volume create "$P-uploads" >/dev/null
+docker volume create "$P-plugins" >/dev/null
+docker run --rm --user root -v "$P-backups":/b -v "$P-uploads":/u -v "$P-plugins":/p \
+  "$IMAGE_BASE-api:$NEXT_TAG" chown node:node /b /u /p
+docker run -d --name "$P-db" --network "$NET" \
+  -e POSTGRES_USER=dorfteich -e POSTGRES_PASSWORD="$PGPASS" -e POSTGRES_DB=dorfteich \
+  postgres:17.5-alpine >/dev/null
+for _ in $(seq 1 30); do
+  docker exec "$P-db" pg_isready -U dorfteich >/dev/null 2>&1 && break
+  sleep 2
+done
+DB1="postgresql://dorfteich:$PGPASS@$P-db:5432/dorfteich"
+
+# --- 1. Update simulation ----------------------------------------------------
+if [ -n "$PREV_TAG" ]; then
+  log "update simulation: $PREV_TAG → $NEXT_TAG"
+  start_api "$DB1" "$PREV_TAG"
+  login
+  seed_fixture "$PREV_TAG"
+  start_api "$DB1" "$NEXT_TAG" # same database: migrations must auto-apply
+  case "$READY" in
+    *'"migrations","status":"ok"'*) log "migrations applied cleanly on upgrade" ;;
+    *) fail "migration state broken after upgrade: $READY" ;;
+  esac
+  login
+  assert_fixture "$NEXT_TAG"
+else
+  log "no previous release — skipping the update simulation (first release)"
+  start_api "$DB1" "$NEXT_TAG"
+  login
+  seed_fixture "$NEXT_TAG"
+fi
+
+# --- 3. Degraded readyz (no sidecars, no backup yet) --------------------------
+case "$READY" in
+  *'"status":"degraded"'*) log "readyz degraded (200) without sidecars — as specified" ;;
+  *) fail "expected degraded readiness without sidecars: $READY" ;;
+esac
+case "$READY" in
+  *'"converter","status":"warn"'*) ;;
+  *) fail "converter check should warn without a sidecar: $READY" ;;
+esac
+
+# --- 2. Backup/restore roundtrip ----------------------------------------------
+log "backup/restore roundtrip with $NEXT_TAG"
+docker run --rm --network "$NET" -e BACKUP_RUN_ONCE=1 \
+  -e DATABASE_URL="$DB1" \
+  -v "$P-backups":/backups -v "$P-uploads":/data/uploads -v "$P-plugins":/data/plugins \
+  "$IMAGE_BASE-backup:$NEXT_TAG" || fail "candidate backup run failed"
+BACKUP_ID=$(docker run --rm -v "$P-backups":/backups:ro "$IMAGE_BASE-backup:$NEXT_TAG" \
+  node -e 'console.log(require("/backups/status.json").lastSuccess.backupId)')
+
+docker run -d --name "$P-db2" --network "$NET" \
+  -e POSTGRES_USER=dorfteich -e POSTGRES_PASSWORD="$PGPASS" -e POSTGRES_DB=dorfteich \
+  postgres:17.5-alpine >/dev/null
+for _ in $(seq 1 30); do
+  docker exec "$P-db2" pg_isready -U dorfteich >/dev/null 2>&1 && break
+  sleep 2
+done
+DB2="postgresql://dorfteich:$PGPASS@$P-db2:5432/dorfteich"
+docker run --rm --network "$NET" -e DATABASE_URL="$DB2" \
+  -v "$P-backups":/backups -v "$P-uploads":/data/uploads -v "$P-plugins":/data/plugins \
+  "$IMAGE_BASE-backup:$NEXT_TAG" node dist/restore.js "$BACKUP_ID" \
+  || fail "restore into the scratch database failed"
+start_api "$DB2" "$NEXT_TAG"
+login
+assert_fixture "restored-$NEXT_TAG"
+
+log "OK — update simulation, degraded readiness, and backup roundtrip all green for $NEXT_TAG"
diff --git a/docs/architecture/deployment.md b/docs/architecture/deployment.md
index a6e0b40..2dd85d2 100644
--- a/docs/architecture/deployment.md
+++ b/docs/architecture/deployment.md
@@ -115,4 +115,8 @@ flowchart LR
   proxy or the `caddy` profile). Setup = compose up + browser wizard.
 - Updates: `docker compose pull && up -d` on a new semver tag; migrations
   run automatically; the release notes flag anything manual. Downgrades are
-  supported one release back.
+  supported one release back. Every release candidate passes the automated
+  operations QA (`deploy/release-qa.sh`, issue #90: update simulation from
+  the previous release, degraded-readyz semantics, backup/restore
+  roundtrip) before the manual prod gate; new migrations add their own
+  fixture to the script's `seed_fixture`/`assert_fixture` pair.