Mockoon vs Pact

Mockoon is a free, open-source tool for designing and running mock APIs locally. It supports OpenAPI and can fit into existing applications and API design workflows. Mock behavior can use dynamic templating, rule matching, JSON databases, proxy mode, webhooks, and TLS. The tool can record requests and responses from a real API to create mocks, and it supports proxying and integration testing. The open-source version permits unlimited mock APIs and routes, including parallel runs. Its CLI can run mocks in headless automated environments such as CI, GitHub Actions, and Docker; mocks can also run in serverless environments including AWS Lambda and GCP/Firebase Functions. The desktop app stores mocks locally, works offline without an account, and reports that mock content and request data are not sent to Mockoon. Pro adds real-time team collaboration, synchronized mocks, and deployment management on private infrastructure; it can be self-hosted on-premises, in a private cloud, or on isolated or air-gapped networks. Team is listed at €10 a month, billed annually at €120/license/year, tax excluded. Eligible companies can request one 14-day self-hosted Pro trial with five license slots using a verified work email, without a payment method.

Pact is a free, code-first tool for testing HTTP and message integrations with contract tests. Automated consumer tests create contracts describing concrete interactions between consumer and provider applications. Teams can then test each side in isolation against that shared contract, without deploying the entire system. Pact implementations are available for more than 10 languages, including JavaScript, Java, .NET, Go, Python, Ruby, Swift and Objective-C, Scala, Rust, PHP, and C++. Its CLI includes mock and stub servers, a provider verifier, a broker client, and a plugin CLI. The open-source Pact Broker shares contracts and verification results; teams can host and administer it themselves, and use its CI/CD workflows to check whether application versions can be deployed together. The verifier supports HTTP and asynchronous and synchronous messages, while plugins include gRPC, Avro, and CSV support. Documentation includes recipes for tools and scenarios such as GraphQL, Cypress, Kafka, and AWS Lambda. Pact is most useful when teams control both consumer and provider development. The free Broker is self-hosted, leaving its security, maintenance, and upgrades to its operator.