Electric — Deployment

Setup

Postgres configuration

# postgresql.conf
wal_level = logical
max_replication_slots = 10

Docker Compose

name: 'electric-backend'
services:
  postgres:
    image: postgres:16-alpine
    environment:
      POSTGRES_DB: electric
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: password
    ports: ['54321:5432']
    volumes: ['./postgres.conf:/etc/postgresql/postgresql.conf:ro']
    tmpfs: ['/var/lib/postgresql/data', '/tmp']
    command: ['postgres', '-c', 'config_file=/etc/postgresql/postgresql.conf']

  electric:
    image: electricsql/electric:latest
    environment:
      DATABASE_URL: postgresql://postgres:password@postgres:5432/electric?sslmode=disable
      ELECTRIC_SECRET: ${ELECTRIC_SECRET}
    ports: ['3000:3000']
    volumes: ['electric_data:/var/lib/electric']
    depends_on: ['postgres']

volumes:
  electric_data:

Electric Cloud

npx @electric-sql/start my-app
pnpm claim && pnpm deploy

Core Patterns

Environment variables

Variable	Required	Description
DATABASE_URL	Yes	Direct Postgres connection (not pooler)
ELECTRIC_SECRET	Yes (prod)	API authentication secret
ELECTRIC_INSECURE	Dev only	Set true to skip secret requirement
ELECTRIC_STORAGE_DIR	No	Persistent shape cache directory
ELECTRIC_POOLED_DATABASE_URL	No	Pooled connection for non-replication queries
ELECTRIC_DATABASE_USE_IPV6	No	Set true for IPv6 Postgres connections

Kubernetes health checks

livenessProbe:
  httpGet:
    path: /v1/health
    port: 3000
readinessProbe:
  exec:
    command: ['curl', '-sf', 'http://localhost:3000/v1/health']
  # Use exec, not httpGet — 202 means "alive but not ready"
  # Only 200 means fully ready for traffic

Replication slot cleanup

-- When stopping Electric for extended periods:
SELECT pg_drop_replication_slot('electric_slot_default');

-- Prevent unbounded WAL growth:
ALTER SYSTEM SET max_slot_wal_keep_size = '10GB';
SELECT pg_reload_conf();

Common Mistakes

CRITICAL Not setting wal_level to logical

Wrong:

# postgresql.conf (default)
wal_level = replica

Correct:

wal_level = logical
max_replication_slots = 10

Electric requires logical replication. The default wal_level = replica does not support it. Requires Postgres restart after change.

Source: packages/sync-service/dev/postgres.conf

CRITICAL Running without ELECTRIC_SECRET in production

Wrong:

docker run electricsql/electric \
  -e DATABASE_URL=postgres://user:pass@host/db

Correct:

docker run electricsql/electric \
  -e DATABASE_URL=postgres://user:pass@host/db \
  -e ELECTRIC_SECRET=my-secret-key

Since v1.x, ELECTRIC_SECRET is required. Without it, Electric refuses to start unless ELECTRIC_INSECURE=true is set (dev only).

Source: packages/sync-service/CHANGELOG.md:832-834

MEDIUM Using ephemeral storage for ELECTRIC_STORAGE_DIR

Wrong:

electric:
  image: electricsql/electric:latest
  # No volume — shape cache lost on restart

Correct:

electric:
  image: electricsql/electric:latest
  volumes: ['electric_data:/var/lib/electric']

Electric caches shape logs on disk. Ephemeral storage causes full re-sync on every container restart.

Source: website/docs/guides/deployment.md:133-157

MEDIUM Using deprecated ELECTRIC_QUERY_DATABASE_URL

Wrong:

ELECTRIC_QUERY_DATABASE_URL=postgres://user:pass@pooler:6432/db

Correct:

ELECTRIC_POOLED_DATABASE_URL=postgres://user:pass@pooler:6432/db

Renamed from ELECTRIC_QUERY_DATABASE_URL to ELECTRIC_POOLED_DATABASE_URL in v1.3.x. The old name may stop working in future versions.

Source: packages/sync-service/CHANGELOG.md:415

See also: electric-proxy-auth/SKILL.md — Production requires proxy with ELECTRIC_SECRET. See also: electric-postgres-security/SKILL.md — Deployment requires correct Postgres configuration. See also: electric-debugging/SKILL.md — Many sync issues stem from deployment configuration.

Version

Targets Electric sync service v1.x.