Sequin
Sequin is an open-source CDC tool that streams PostgreSQL changes to queues, streaming platforms, and webhooks with strict ordering and exactly-once processing, shipped as a Docker image rather than a Postgres extension.
LicenseOpen source (permissive)· MIT
DeploymentSelf-hosted
PricingFree
Operational complexityLow
WorkloadStreaming
LanguageElixir
Use it when
- Application services, not just the warehouse, consume database changes: Kafka, SQS, SNS, Kinesis, Pub/Sub, Redis, NATS, and plain webhooks are all first-class sinks.
- Guarantees must be strong and simple: strict ordering and exactly-once processing through idempotency keys, stated plainly.
- Replays should be routine, not incidents; sinks backfill and individual rows replay on demand.
- The source is managed Postgres where extensions are off-limits; Sequin works against any Postgres 14+ from outside.
Think twice when
- Sources other than PostgreSQL exist; there is no other path (Debezium is the multi-source answer).
- You want a hosted service with support; Sequin Cloud closed in 2025, leaving self-hosting only.
- Warehouse loading with schema management is the goal; messages carry rows as-is, and destination schema evolution is not the model.
How it runs
One container beside a Postgres and Redis, against a source with wal_level=logical, a publication, and a replication slot. Filters, transforms, and routing are configured per sink; delivery is sub-second from commit. MIT-licensed and free, with a console, CLI, and API.
Details
CompareHow Sequin answers the questions Change Data Capture turns on.
Change Data Capture
| How it works | |
| Initial snapshot | Backfill per sink; individual rows replayable |
| End-to-end lag | Sub-second: measured from commit to delivery at the sink |
| Delivery guarantee | Exactly-once: idempotency keys · strict ordering |
| Schema drift | Messages carry the row as-is; no destination schema to migrate |
| Running it | |
| What you run | One container, with Postgres and Redis beside it |
| Connections | |
| Sources | PostgreSQL 14+ only |
| Source requirements | wal_level logical, plus a publication and replication slot |
| Transformations | Filters, transforms and routing, configured per sink |
| Destinations | Kafka, SQS, SNS, Kinesis, Pub/Sub, Redis, NATS, webhooks |
| Cost | |
| Billing unit | None: Sequin Cloud closed in 2025; self-hosting only |
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