Hoppscotch — Open-Source API Development Platform

What it is

Hoppscotch is an open-source API development platform that provides a fast, beautiful interface for testing REST, GraphQL, WebSocket, SSE, and gRPC APIs. It runs in the browser, requires no installation, and can be self-hosted for teams. Features include environment variables, collections, history, and team collaboration.

It targets developers who need a lightweight, privacy-respecting alternative to Postman for API testing and development.

How it saves time or tokens

Hoppscotch loads instantly in the browser without installing a desktop application. The clean interface lets you quickly test API endpoints, inspect responses, and organize requests into collections. For AI API development, you can test your model endpoints, verify response formats, and share collections with team members. The WebSocket and SSE support is particularly useful for testing streaming AI response endpoints.

How to use

1. Use instantly at hoppscotch.io -- no account needed.

1. Self-host for your team:

git clone https://github.com/hoppscotch/hoppscotch.git
cd hoppscotch
docker compose up -d

1. Test an API:

• Select request method (GET, POST, PUT, etc.)
• Enter URL
• Add headers and body
• Click Send
• Inspect the response

Example

# Test an AI API endpoint using Hoppscotch:
# 1. Set method to POST
# 2. URL: https://api.openai.com/v1/chat/completions
# 3. Headers:
#    Authorization: Bearer sk-your-key
#    Content-Type: application/json
# 4. Body (JSON):
{
  "model": "gpt-4o",
  "messages": [
    {"role": "user", "content": "Hello, world"}
  ],
  "stream": false
}
# 5. Click Send and inspect the response

# For streaming responses, use the SSE client:
# Connect to your streaming endpoint and watch tokens arrive

Related on TokRepo

• AI tools for API -- API development and management tools
• AI tools for testing -- Testing tools and frameworks

Common pitfalls

• Browser-based API testing is subject to CORS restrictions. Some APIs may not respond to requests from a browser. Use the Hoppscotch browser extension or self-hosted proxy to bypass CORS.
• Self-hosting requires PostgreSQL and email configuration for team features. The public instance at hoppscotch.io works without setup for individual use.
• Large response bodies can slow down the response viewer. For APIs returning megabytes of data, consider limiting response size or using a CLI tool instead.