API development tools help developers design, test, document, and monitor APIs. The category includes API clients (Postman, Insomnia), documentation platforms (Swagger, Stoplight), and emerging tools that combine both workflows.

The trend is toward open-source and lightweight alternatives. While Postman remains dominant, its increasing complexity has pushed many developers toward simpler tools like Hoppscotch, Bruno, and Thunder Client. Open-source options offer the advantage of Git-friendly collections that can be version-controlled alongside code.

When choosing API development tools, consider whether you need team collaboration features, how important offline access is, and whether you prefer cloud-synced or Git-based collection storage. For many developers, a simple VS Code extension is all they need.

All api development tools

1
Postman Free tier

API development platform for designing, testing, documenting, and monitoring APIs.

Free for 3 users · Free API developers wanting a complete API platform
Collections Mock Servers Monitoring Docs
2
Insomnia Free tier Open Source

Open-source API client for REST, GraphQL, and gRPC with environment variables and plugin support.

Free for individuals · Free Developers wanting a lightweight REST and GraphQL client
REST GraphQL gRPC Plugins
3
Hoppscotch Free Open Source

Open-source API development ecosystem with real-time WebSocket testing and team collaboration.

Free Developers wanting a fast, open-source API client
Open Source Real-Time WebSocket Team Collab
4
Bruno Free Open Source

Open-source API client that stores collections as files on your filesystem — Git-friendly and offline-first.

Free Developers wanting a Git-friendly API client
Git-Friendly Offline-First Scripting No Cloud
5
RapidAPI Free tier

API marketplace and development platform for finding, testing, and managing third-party APIs.

Free tier available · Free Developers wanting to discover, test, and connect APIs
API Marketplace Testing Hub Enterprise Gateway
6
Swagger Free Open Source

Open-source API development framework with the OpenAPI specification.

Free API developers wanting standardized API documentation
OpenAPI Spec Code Gen UI Editor
7
Stoplight Free tier

API design, documentation, and governance platform with OpenAPI support.

Free for 1 project · Free API teams wanting design-first API development
API Design Mock Servers Style Guides Docs
8

Lightweight REST API client built into VS Code with collections and environments.

Free VS Code users wanting a lightweight API client
VS Code Extension Collections CLI Git Sync
9

Native macOS API client with code generation, environments, and team sync.

Paid from $49.99 one-time macOS developers wanting a native API client
Native macOS Code Gen Dynamic Values Extensions
10
Apidog Free tier

All-in-one platform for API design, debugging, testing, documentation, and mocking.

Free for 3 users · Free API teams wanting an all-in-one API development platform
API Design Debugging Mock Server Automation

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Frequently asked questions

Is Postman still the best API client?
Postman has the most features and largest community, but it's become bloated for many use cases. If you want something simpler, Bruno (offline-first, Git-friendly) and Hoppscotch (web-based, open-source) are excellent alternatives. Thunder Client is great if you live in VS Code.
What's the best way to document APIs?
For RESTful APIs, use the OpenAPI (Swagger) specification as your source of truth. Then choose a rendering tool: Swagger UI for basic docs, Mintlify or ReadMe for polished developer portals, or Redocly for OpenAPI-first workflows. Auto-generating docs from your spec ensures they stay in sync.
Should API collections be stored in the cloud or in Git?
Git-based storage (Bruno, Thunder Client) is better for version control and team collaboration through existing Git workflows. Cloud-based storage (Postman, Insomnia) is more convenient for sharing and onboarding. For teams that already use Git heavily, file-based collections are the better long-term choice.

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