Best Free API AI tools

APIPark is an open-source AI gateway and API portal that simplifies AI model management, integration, and deployment, offering unified API formatting, lifecycle management, and secure multi-tenant support for efficient AI usage.

Aspen is a MacOS native API testing tool with a secure, zero-trust environment. Its AI assistant streamlines testing, generates integration code, and optimizes REST API testing. Developed by Treblle, Aspen integrates efficiency and security for seamless API testing and integration processes.

ReAPIs accelerates API development using AI-driven tools. Simplifies YAML tasks via visual editor, automates documentation, ensures precision, boosts reusability, and facilitates collaboration for streamlined and precise API creation.

Compresr is an open-source context-compression library for LLM pipelines and agents, offering coarse chunk selection and fine-grained token-level compression to shrink conversation history, documents, and tool outputs—reducing inference latency and token costs while preserving task accuracy.