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PgCat

github.com

Free plan LinuxSelf-hosted
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Spec score 7.6 #15 of 31 in Database Proxy Software

What it is

PgCat is a free, open-source PostgreSQL pooler and proxy for self-hosted Linux deployments. Its stable features include transaction and session pooling. Read queries can be balanced across replicas and the primary, while health checks detect broken replicas and redirect queries to remaining servers. PgCat uses Tokio’s asynchronous runtime and a multithreaded design for multicore machines. Operators can view pooler statistics through the pgcat and pgbouncer admin databases or a Prometheus HTTP endpoint. Client and PostgreSQL server connections can use SSL/TLS, with MD5 and SCRAM-SHA-256 authentication supported. MD5 passthrough can use auth_query so cleartext passwords need not be stored in the configuration file. Docker deployment is documented, and a container image is published. Sharding syntax, comment parsing, automatic sharding, and mirroring are experimental. Transaction mode is enabled by default and does not support prepared statements, SET, or advisory locks. The project describes PgCat as stable and says it serves high query volumes in production. It is licensed under MIT.

Spec sheet

Purpose
PgCat is a PostgreSQL pooler and proxy supporting sharding, load balancing, failover and mirroring.Read 1 Oct 2026 · github.com
Deployment
The project documents Docker deployment and publishes ghcr.io/postgresml/pgcat:latest.Read 1 Oct 2026 · github.com
Security
Clients and PostgreSQL servers can use SSL/TLS, and authentication supports MD5 and SCRAM-SHA-256 connections.Read 1 Oct 2026 · github.com
License
PgCat is free and open source under the MIT license.Read 1 Oct 2026 · github.com
Maker
PostgresML was founded in 2022 by engineers who built Instacart’s machine learning platform.Read 1 Oct 2026 · postgresml.org
Authentication
MD5 auth passthrough can use auth_query so cleartext passwords are not required in the configuration file.Read 1 Oct 2026 · github.com
Failover
Broken replicas are detected with health checks and queries are rerouted to remaining servers.Read 1 Oct 2026 · github.com
Mirroring
Mirroring is an experimental feature that sends queries to multiple databases for testing or replica prewarning.Read 1 Oct 2026 · github.com
Monitoring
Pooler statistics are available through the pgcat and pgbouncer admin databases and through a Prometheus HTTP endpoint.Read 1 Oct 2026 · github.com
Pooling
Transaction pooling and session pooling are stable features.Read 1 Oct 2026 · github.com
Production status
The project says PgCat is stable and used in production to serve hundreds of thousands of queries per second.Read 1 Oct 2026 · github.com
Read balancing
Read queries can be automatically load balanced between replicas and the primary.Read 1 Oct 2026 · github.com
Runtime
PgCat uses Tokio’s asynchronous runtime and a multithreaded design for multicore machines.Read 1 Oct 2026 · github.com
Sharding
Extended SQL syntax, comment parsing and automatic sharding are experimental features.Read 1 Oct 2026 · github.com
Transaction-mode limit
Transaction mode is enabled by default and does not support prepared statements, SET or advisory locks.Read 1 Oct 2026 · github.com

Plans and prices

Open source Free MIT license · self-hosted Read 1 Oct 2026 · github.com

Every PgCat plan and price →

Strong points and limits

Strong points

  • Stable transaction and session pooling
  • Read balancing across replicas and primary
  • Health checks reroute queries around broken replicas
  • Prometheus endpoint exposes pooler statistics
  • Supports SSL/TLS and two authentication methods

Limits

  • Sharding features are experimental
  • Mirroring is experimental
  • Transaction mode excludes prepared statements, SET, and advisory locks

Who it suits

PgCat suits teams operating PostgreSQL who need self-hosted connection pooling, query routing, and failover on Linux. Its documented deployment options and monitoring endpoints are aimed at operators managing the pooler.

Verdict

PgCat offers core pooling, read balancing, and failover, with monitoring and connection security options. Treat sharding and mirroring as experimental, and account for transaction-mode restrictions.

Where Specifiction places it

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