PgCat
PgCat is a free, open-source PostgreSQL pooler and proxy for self-hosted Linux deployments.
What PgCat is
PgCat is a free, open-source PostgreSQL pooler and proxy for self-hosted Linux deployments. It supports transaction and session pooling, and can route read queries across replicas and the primary. Health checks detect broken replicas so queries can be redirected to remaining servers. PgCat uses Tokio’s asynchronous runtime and a multithreaded design for multicore machines. Pooler statistics are available through its admin databases and a Prometheus HTTP endpoint. It also supports SSL/TLS connections and MD5 or SCRAM-SHA-256 authentication. Docker deployment is documented, and a container image is published. Some capabilities have experimental status: sharding features and mirroring. Transaction mode is enabled by default and does not support prepared statements, SET, or advisory locks. The project describes PgCat as stable and reports production use at high query volumes. It is licensed under MIT and supports PostgreSQL.
Good
- Free and open source under the MIT license.
- Supports transaction and session pooling.
- Can reroute queries after replica health checks.
- Provides statistics through admin databases and Prometheus.
Watch out
- Transaction mode does not support prepared statements.
- Transaction mode excludes SET and advisory locks.
- Sharding and mirroring features are experimental.
Who it suits
PgCat may suit teams running PostgreSQL who want self-hosted connection pooling, query routing, or replica failover. Its transaction-mode limitations and experimental sharding and mirroring features matter when evaluating a deployment.
Verdict
PgCat provides PostgreSQL pooling and routing in a self-hosted package, with monitoring, authentication, and failover features. Check transaction-mode limitations and the experimental status of sharding and mirroring against your needs.
Plans and prices
From PgCat's own pricing page, checked 1 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Open source | Free | MIT license · self-hosted |
The facts
Each one read from PgCat's own pages, with the date it was checked.
What it does
- Authentication
- MD5 auth passthrough can use auth_query so cleartext passwords are not required in the configuration file.checked 1 Oct 2026
- Deployment
- The project documents Docker deployment and publishes ghcr.io/postgresml/pgcat:latest.checked 1 Oct 2026
- Failover
- Broken replicas are detected with health checks and queries are rerouted to remaining servers.checked 1 Oct 2026
- License
- PgCat is free and open source under the MIT license.checked 1 Oct 2026
- Mirroring
- Mirroring is an experimental feature that sends queries to multiple databases for testing or replica prewarning.checked 1 Oct 2026
- Monitoring
- Pooler statistics are available through the pgcat and pgbouncer admin databases and through a Prometheus HTTP endpoint.checked 1 Oct 2026
- Pooling
- Transaction pooling and session pooling are stable features.checked 1 Oct 2026
- Production status
- The project says PgCat is stable and used in production to serve hundreds of thousands of queries per second.checked 1 Oct 2026
- Purpose
- PgCat is a PostgreSQL pooler and proxy supporting sharding, load balancing, failover and mirroring.checked 1 Oct 2026
- Read balancing
- Read queries can be automatically load balanced between replicas and the primary.checked 1 Oct 2026
- Runtime
- PgCat uses Tokio’s asynchronous runtime and a multithreaded design for multicore machines.checked 1 Oct 2026
- Security
- Clients and PostgreSQL servers can use SSL/TLS, and authentication supports MD5 and SCRAM-SHA-256 connections.checked 1 Oct 2026
- Sharding
- Extended SQL syntax, comment parsing and automatic sharding are experimental features.checked 1 Oct 2026
- Transaction-mode limit
- Transaction mode is enabled by default and does not support prepared statements, SET or advisory locks.checked 1 Oct 2026
The company
- Maker
- PostgresML was founded in 2022 by engineers who built Instacart’s machine learning platform.checked 1 Oct 2026
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