Echolon

Echolon is a modern, open-source API client designed for developers who need a powerful, privacy-focused tool for API development. Built with a local-first architecture, it stores all data locally as plain text files that work seamlessly with Git, eliminating the need for mandatory cloud sync or account creation. It serves as a lightweight alternative to Postman with support for REST, WebSocket, and upcoming GraphQL protocols.

• Open Source & Local-First - All your data stays on your machine with no forced cloud sync or account requirements. Collections, environments, and settings are stored locally as plain text files.

• Git Integration - Full native Git support with visual interface for staging changes, committing, pushing, and pulling. Your API collections are always version-controlled with visual diff viewer and branch management.

• Multi-Protocol Support - Work with REST/HTTP and WebSocket APIs within a single workspace. GraphQL support is on the roadmap.

• Advanced Request Editor - Powerful editing with rich content type previews (JSON, XML, HTML, images), JSON-Path filtering for quick data extraction, and live schema validation against OpenAPI specs.

• Powerful Variable System - Define variables in headers, query parameters, body, or scripts. Use built-in dynamic functions like $timestamp, $uuid, $random, and JavaScript expressions for complex logic.

• Comprehensive Authentication - Automatically handle complex request authentication including Basic, Bearer, API Key, Digest, OAuth 2.0, AWS v4, and JWT.

• API Mocking - Create mock servers instantly with 1-click mocking for any API response using local or cloud proxy. Real-time request monitoring with custom response bodies, headers, delays, and status code simulation.

• One-Click API Publishing - Publish beautiful, interactive API documentation to the web with a single click. Share API references with your team or publicly.

• Import/Export - One-click import from Postman, Insomnia, Bruno, OpenAPI/Swagger specs, and cURL commands. Export requests to cURL, JavaScript, Python, and more.

• Offline Mode - Built with offline-first architecture so you can work without internet connectivity.

To get started, download Echolon for free from the website or use the web app. Import your existing collections from Postman or other tools, or create new workspaces and start making API requests immediately. All core features are available in the free Personal tier.