apgdiff

apgdiff is a free Java command-line utility for turning differences between two PostgreSQL schema dumps into update SQL. It is best suited to developers and database administrators who already work in terminals and need a scriptable step in batch jobs or web applications. Its focused PostgreSQL remit is useful, but the generated DDL demands inspection before it becomes a production migration.

Overview

You supply an older schema dump and a newer one; apgdiff compares them and either prints the resulting DDL or redirects it to a file. That workflow fits automated pipelines and repeatable migration preparation better than teams looking for a graphical database workbench. The scope is deliberately narrow: it compares PostgreSQL schemas, not several database engines or live databases as a general administration environment.

The project is MIT licensed and costs nothing. Version 2.4 is identified as the latest stable release, with binary and source ZIP downloads; that release dates from 2012. GitHub Issues handles bug reports and feature requests. The age of the stable release is a practical consideration for teams whose PostgreSQL syntax or delivery process changes quickly.

Key features

apgdiff can generate migration scripts from schema snapshots, making it suitable when the desired artifact is executable DDL rather than a visual report. Its supported statement set includes selected ALTER SEQUENCE, ALTER TABLE, ALTER VIEW, COMMENT, CREATE FUNCTION, CREATE INDEX, CREATE SCHEMA, CREATE SEQUENCE, CREATE TABLE, CREATE TRIGGER, CREATE VIEW and SET search_path forms. Projects whose changes stay within those constructs can use it as a compact diff-to-migration step.

Coverage is selective rather than a promise to understand every statement in a dump. SQL outside the supported set is ignored, and the --output-ignored-statements option can report those omissions. CREATE TABLE column constraints are limited to NULL and NOT NULL, so schemas relying on richer column-level constraints need a separate review and likely additional migration work. The usage guidance calls for checking generated upgrade statements and, where appropriate, trying them against another database before production; that is essential here, not optional polish.

Because it is a terminal program, it can be called from batches and web applications and suits command-line-oriented teams. Users who expect an interactive editor or visual comparison experience will find the workflow less convenient.

Pricing

Free — free. The plan is the complete MIT-licensed utility, with no paid tier, trial period or renewal term. It is a good fit for individual developers and teams that can supply their own automation and validation around PostgreSQL dump comparisons. The trade-off is not a metered quota but the tool's limited SQL coverage and the need to manage review, testing and deployment yourself.

Platforms

apgdiff runs on Linux, macOS and Windows. The project also lists Solaris and BSD, and says other systems can work when Java is available. Installation requires Java 1.6 or newer. Binary and source ZIP packages provide deployment choices, while the Java runtime requirement adds an environment dependency to otherwise simple command-line installation.

Who it's for

Choose apgdiff when your team maintains PostgreSQL schemas as dumps, is comfortable invoking CLI tools, and wants generated DDL that can be redirected into a migration file or pipeline step. It is particularly suitable for narrowly defined schema changes covered by its supported statements.

It is a weaker fit for teams needing broad SQL-language coverage, a graphical workflow, cross-database comparisons, or confidence that every dump statement will be interpreted. If your schema uses constraints beyond NULL and NOT NULL or routinely includes unsupported SQL, plan a manual migration process around the output rather than treating it as a complete answer.

Pros and cons

Pros

Free and MIT licensed: there is no purchase barrier or recurring fee for using the utility.

Migration-oriented output: differences can be printed or saved directly as DDL for a downstream workflow.

Automation-friendly CLI: terminal invocation works well in batches and web applications across major desktop and server platforms.

Ignored-statement reporting: the dedicated option helps identify SQL that the parser did not handle.

Cons

Selective SQL support: unsupported statements are ignored, which can leave a generated migration incomplete.

Restricted column constraints: CREATE TABLE handling supports only NULL and NOT NULL constraints.

PostgreSQL only: it cannot serve a multi-engine schema comparison strategy.

Terminal-first operation: users who need a visual diff or editor may find the workflow cumbersome.

Old stable release: version 2.4 was released in 2012, a concern for long-lived, evolving database programs.

Alternatives

For a broader directory of options, see Database Schema Comparison Tools.

dbForge Studio for PostgreSQL is the better direction when you want a freemium product with a free trial and a Linux, macOS or Windows interface-oriented toolkit.

Pick Redgate SQL Provision instead when provisioning or masking production data across capacity tiers matters more than a free schema-diff CLI.

Skeema suits teams wanting a freemium workflow with a free Community plan and a paid Plus tier, including schema-oriented linting and broader development tooling.

Consider SQL Delta if you specifically need a paid Windows comparison product with a free trial.

sqldef is another free, MIT-licensed open-source CLI option for teams comparing schemas across Linux, macOS, Windows and self-hosted environments.

dbdiff offers a free schema-comparison alternative for Linux, macOS, Windows and self-hosted use.

DBDiff is a free open-source option available on Linux, macOS and Windows.

DBC is another free choice supporting Linux, macOS and Windows.

Verdict

apgdiff is a sensible pick for PostgreSQL-focused, command-line teams that need no-cost DDL generation from schema dumps and can enforce review in their migration process. Choose it for that narrow, automatable job; look elsewhere if incomplete SQL coverage, an aging release, richer constraints or a graphical and cross-engine workflow would create unacceptable risk.