michaelsogos/pg-diff

PostgreSQL schema and data comparing tool.

Summary

pg-diff is an open-source command-line tool for comparing PostgreSQL databases. The repository is a JavaScript project distributed on npm, tagged for PostgreSQL, SQL, and Node.js use cases, and released under the MIT license. Its stated purpose is to compare both schema definitions and data between PostgreSQL sources.

What it is useful for

The repository describes pg-diff as a tool for comparing PostgreSQL schema and data, which is a common task during database change management. Typical use cases for tools in this category include checking whether two databases are structurally identical before a migration, reviewing the difference between a development environment and production, generating a change set that can be reviewed or applied to another environment, and auditing data drift between replicas or after an ETL job. Because the project is published as a CLI on npm, it can be wired into scripts, CI pipelines, or local development workflows where reproducible database comparisons are needed. The MIT license and Node.js packaging also make it straightforward to distribute inside teams and to depend on from other JavaScript tooling.

How engineers can use it

The README provided here is intentionally minimal: it states the purpose, points to the project's documentation site for full details, and offers a PayPal support link. No installation command, configuration file, CLI flags, connection-string format, or worked example is included in the README itself.

Because the README does not document setup, the following should be confirmed against the external documentation before relying on the tool:

• Installation method. The repository is published as an npm package, so installation is likely via npm install, but the exact command and package name are not stated in the README.
• Connection requirements. A tool of this kind typically needs read access to one or more PostgreSQL databases, including credentials and host/port information; the README does not specify the expected input format.
• Output format and scope. The README confirms that both schema and data can be compared, but it does not describe whether the output is SQL statements, JSON, a unified diff, or something else, nor how schemas versus tables versus row-level data are selected.
• Limitations. No supported PostgreSQL versions, performance characteristics, or known caveats are documented in the README, so these should be verified in the documentation site before use in production pipelines.

In short, pg-diff positions itself as a general-purpose PostgreSQL comparison tool, but engineers should treat the documentation site as the authoritative source for installation and usage details.