Pact

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Introduction

JS version of Pact. Pact is a contract testing framework for HTTP APIs and non-HTTP asynchronous messaging systems.

The latest GitHub release listed on 25 Oct 2026 was v17.1.4, published 2026-09-07.

Features

These items are quoted from public documentation fetched on 25 Oct 2026. Taken from repository README headings.

1. Documentation: This readme offers a basic introduction to the library. The full documentation for Pact JS and the rest of the framework is available at https://docs.pact.io/.
2. Tutorial (60 minutes): Learn the key Pact JS features in 60 minutes: https://github.com/pact-foundation/pact-workshop-js
3. Need Help: - Join our community slack workspace. - Stack Overflow: https://stackoverflow.com/questions/tagged/pact - Say 👋 on Twitter: [@pactup]
4. Requirements: 1. If using pact-js v11 or lower, 1. make sure the ignore-scripts option is disabled, pact uses npm scripts to compile native dependencies and won’t function without it. 2. Pact uses native extensions and installs them via the node-gyp package. This requires a build chain for a successful installation. See also issue…
5. Consumer package: The main consumer interfaces are the PactV3 class and MatchersV3 exports of the @pact-foundation/pact package.
6. Provider package: The main provider interface is the Verifier class of the @pact-foundation/pact package.

Pros

Points stated in the public sources fetched on 25 Oct 2026:

1. Repository topics: The repository’s GitHub topics include consumer-driven-contracts, hacktoberfest, mocha, pact, pact-js, smartbear-supported, test-framework.

Cons

The pages fetched on 25 Oct 2026 do not publish a limitations list. That absence is not evidence that the tool has no drawbacks. Current issues are tracked at https://github.com/pact-foundation/pact-js/issues.

Usage and Links (Example)

The repository README includes this example (from “Provider package”):

const { Verifier } = require('@pact-foundation/pact');

// (1) Start provider locally. Be sure to stub out any external dependencies
server.listen(8081, () => {
  importData();
  console.log('Animal Profile Service listening on http://localhost:8081');
});

// (2) Verify that the provider meets all consumer expectations
describe('Pact Verification', () => {
  it('validates the expectations of Matching Service', () => {
    let token = 'INVALID TOKEN';

    return new Verifier({
      providerBaseUrl: 'http://localhost:8081', // <- location of your running provider
      pactUrls: [ path.resolve(process.cwd(), "./pacts/SomeConsumer-SomeProvider.json") ],
    })
      .verifyProvider()
      .then(() => {
        console.log('Pact Verification Complete!');
      });
  });
});

Resources:

• Pact website
• GitHub repository
• GitHub release v17.1.4

Pricing

No public price was found on the pages fetched on 25 Oct 2026. This rewrite does not guess a number. Check the official website before treating the tool as free or paid.

Recommended for?

The fetched pages do not name a target audience. Decide fit from the official description and the feature list above.

Conclusion

Pact is summarized by its public description as: “Fast, easy and reliable testing for integrating web apps, APIs and microservices.”.

The latest GitHub release listed was v17.1.4, published 2026-09-07.

This page was rebuilt on 25 Oct 2026 from pact.io, github.com. It keeps only what those pages stated. Confirm the current product, license, and price on the official site before you adopt it.