diff --git a/.gitignore b/.gitignore
index 24f0cd2..dc70e1e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,3 +18,6 @@
 /dev/redis/data/
 /dev/stripe-stub/.env
 /dev/bandwidth-worker/.env
+
+# Backup service secrets (DB passwords + borg passphrase)
+/backup/.env
diff --git a/README.md b/README.md
index 149b9d0..f3f32d7 100644
--- a/README.md
+++ b/README.md
@@ -49,3 +49,47 @@ After editing a function, `cd /docker/supabase && docker compose restart functio
 - `supabase-edge-functions` reads `REDIS_URL` from `/docker/supabase/.env`.
 - bandwidth-worker polls `http://frps:7500/api/proxy/http` every 60s; deltas go
   to `public.usage_samples` and `public.tunnels.bytes_used` via PostgREST.
+
+## Backups
+
+Daily encrypted backups via **borgmatic** (`/docker/backup`).
+
+| Service   | Compose dir     | Container | Schedule            | Image                                          |
+|-----------|-----------------|-----------|---------------------|------------------------------------------------|
+| borgmatic | /docker/backup  | borgmatic | daily 03:00 (Berlin)| ghcr.io/borgmatic-collective/borgmatic:latest  |
+
+- **Source:** `/docker` (mounted read-only). **Repository:** `/var/backups/borg`
+  (local host disk for v1; remote planned later). **Encryption:** repokey-blake2.
+- **Databases:** prod (`supabase-db`) + dev (`supabase-dev-db`) captured via
+  `pg_dumpall` (roles + all DBs), streamed into the archive. The container is
+  attached to `supabase_default` + `supabase-dev_default` to reach them.
+- **Excluded:** live PG data dirs (`supabase/volumes/db/data`), logs,
+  `caddy/.../autosave.json`, `.remediation-backup`, `node_modules`, `.next`.
+- **Retention:** keep_daily 7, keep_weekly 4, keep_monthly 6.
+- **Schedule:** built-in cron via `BACKUP_CRON` env (`0 3 * * *`), running
+  `borgmatic --stats -v 0` (default action set: prune, compact, create, check).
+- **Secrets:** `/docker/backup/.env` (chmod 600, gitignored) holds
+  `POSTGRES_PASSWORD_PROD`, `POSTGRES_PASSWORD_DEV`, `BORG_PASSPHRASE`.
+  **Store `BORG_PASSPHRASE` offsite — losing it makes the repo unrecoverable.**
+
+### Operations
+
+```sh
+cd /docker/backup
+docker compose up -d                                  # start the scheduler
+docker compose run --rm --entrypoint borgmatic borgmatic list           # archives
+docker compose run --rm --entrypoint borgmatic borgmatic create --stats # manual backup
+docker compose run --rm --entrypoint borgmatic borgmatic check          # verify integrity
+```
+
+Restore a database dump:
+
+```sh
+cd /docker/backup
+ARCH=$(docker compose run --rm --entrypoint borgmatic borgmatic list --json \
+  | python3 -c "import sys,json;print(json.load(sys.stdin)[0][\"archives\"][-1][\"archive\"])")
+docker compose run --rm -v /tmp/restore:/restore --workdir /restore \
+  --entrypoint borgmatic borgmatic extract --archive "$ARCH" \
+  --path "borgmatic/postgresql_databases/supabase-db:5432/all"
+# then: psql -U postgres -f /tmp/restore/borgmatic/postgresql_databases/supabase-db:5432/all
+```
diff --git a/backup/.gitignore b/backup/.gitignore
new file mode 100644
index 0000000..4cd5d48
--- /dev/null
+++ b/backup/.gitignore
@@ -0,0 +1,2 @@
+# Never commit secrets.
+.env
diff --git a/backup/borgmatic.d/config.yaml b/backup/borgmatic.d/config.yaml
new file mode 100644
index 0000000..d036cc4
--- /dev/null
+++ b/backup/borgmatic.d/config.yaml
@@ -0,0 +1,74 @@
+# borgmatic configuration for linumiq.net — local encrypted daily backup (v1).
+# borgmatic 2.x flat schema. Secrets are interpolated from the container
+# environment (see ../.env): POSTGRES_PASSWORD_PROD, POSTGRES_PASSWORD_DEV,
+# BORG_PASSPHRASE.
+
+# ---------------------------------------------------------------------------
+# What to back up (files)
+# ---------------------------------------------------------------------------
+source_directories:
+    - /docker
+
+# Repository (bind-mounted from host /var/backups/borg).
+repositories:
+    - path: /repository
+      label: linumiq-local
+
+# Encryption passphrase (repokey-blake2). Set in ../.env, kept offsite too.
+encryption_passphrase: ${BORG_PASSPHRASE}
+
+# ---------------------------------------------------------------------------
+# Exclusions: raw live PG data (captured via logical dumps below), transient
+# logs, regenerable build artifacts, and remediation snapshots.
+# ---------------------------------------------------------------------------
+exclude_patterns:
+    - /docker/supabase/volumes/db/data
+    - /docker/dev/supabase/volumes/db/data
+    - /docker/supabase/volumes/logs
+    - /docker/dev/supabase/volumes/logs
+    - /docker/caddy/config/caddy/autosave.json
+    - sh:/docker/**/.remediation-backup
+    - sh:/docker/**/node_modules
+    - sh:/docker/**/.next
+exclude_caches: true
+exclude_if_present:
+    - .nobackup
+
+# Keep the archive listing manageable.
+one_file_system: false
+
+# ---------------------------------------------------------------------------
+# Postgres logical dumps (streamed into the archive, not written to disk).
+# name "all" => pg_dumpall (roles + all databases + extensions).
+# ---------------------------------------------------------------------------
+postgresql_databases:
+    - name: all
+      hostname: supabase-db
+      port: 5432
+      username: postgres
+      password: ${POSTGRES_PASSWORD_PROD}
+    - name: all
+      hostname: supabase-dev-db
+      port: 5432
+      username: postgres
+      password: ${POSTGRES_PASSWORD_DEV}
+
+# ---------------------------------------------------------------------------
+# Retention
+# ---------------------------------------------------------------------------
+keep_daily: 7
+keep_weekly: 4
+keep_monthly: 6
+
+# Tag archives so prune groups them correctly.
+archive_name_format: "linumiq-{now:%Y-%m-%dT%H:%M:%S}"
+match_archives: "sh:linumiq-*"
+
+# ---------------------------------------------------------------------------
+# Consistency checks (run as part of the default daily action set).
+# ---------------------------------------------------------------------------
+checks:
+    - name: repository
+    - name: archives
+
+# Surface command output/errors in logs.
diff --git a/backup/docker-compose.yml b/backup/docker-compose.yml
new file mode 100644
index 0000000..588fe9d
--- /dev/null
+++ b/backup/docker-compose.yml
@@ -0,0 +1,40 @@
+name: backup
+services:
+  borgmatic:
+    image: ghcr.io/borgmatic-collective/borgmatic:latest
+    container_name: borgmatic
+    hostname: linumiq-borgmatic
+    restart: unless-stopped
+    security_opt:
+      - no-new-privileges:true
+    environment:
+      TZ: Europe/Berlin
+      # Daily backup at 03:00 server-local time. The image writes this to
+      # /etc/crontabs/root and runs: borgmatic --stats -v 0
+      BACKUP_CRON: "0 3 * * *"
+    env_file:
+      - ./.env
+    volumes:
+      # Backup source (read-only — borgmatic never writes to /docker).
+      - /docker:/docker:ro
+      # Local borg repository (host-side, same disk; remote planned later).
+      - /var/backups/borg:/repository
+      # borgmatic configuration.
+      - ./borgmatic.d:/etc/borgmatic.d:ro
+      # Persist borg cache + security dir across container recreation so borg
+      # does not re-scan the whole repo or warn about an "unknown" repository.
+      - borg_cache:/root/.cache/borg
+      - borg_security:/root/.config/borg
+    networks:
+      # Reach the prod + dev Postgres containers (supabase-db / supabase-dev-db)
+      # by container name for the pg_dumpall hook.
+      - supabase_default
+      - supabase-dev_default
+volumes:
+  borg_cache:
+  borg_security:
+networks:
+  supabase_default:
+    external: true
+  supabase-dev_default:
+    external: true