Looking to replace Postman? These open source alternatives give you the same core workflow without the lock-in - free to use, often self-hostable, and auditable on GitHub. Compare licenses, languages and project activity, then switch on your own terms.
Kong is a cloud-native, platform-agnostic gateway for API, LLM, and MCP traffic. It centralizes proxying and routing for microservices or conventional APIs, and it can sit in front of agentic LLM and MCP workloads as a control layer.
Microcks is a Kubernetes-native tool for API mocking and testing. It turns your API and microservices artifacts into live, running mocks, so teams can exercise an API before or alongside the real implementation.
WSO2 API Manager is a platform for building, integrating, exposing, and managing digital services as APIs. It supports API developers and API product managers who need to publish APIs, manage their lifecycle, and create API products from one or more APIs.
Gravitee API Management, also called Gravitee APIM, controls who can access your APIs, and when and how. It documents, discovers, and publishes APIs while managing the full lifecycle, from registration through retirement.
