Best API Clients in 2026

The Collaboration Platform for API Development.

Key Postman features:

User-Friendly Interface Collaboration Comprehensive Testing Tools Extensive API Documentation

Open Source

Create production-ready applications with zero code.

Key Modelence features:

Full-Stack JavaScript Framework Built-in Backend Services Simplified Deployment Rapid Prototyping and Development

Try for free freemium $9 / Monthly

Bruno is a Git-integrated, fully offline, and open-source API client.

Key Bruno features:

User-Friendly Interface Comprehensive Feature Set Regular Updates Strong Customer Support

Open Source

A Powerful API Mocking and Testing Tool.

Key Requestly features:

Redirect URL Block Network Requests Modify Request & Response Header Modify Response

Open Source freemium

Design, debug, test, and mock APIs locally, on Git, or cloud. Build better APIs collaboratively for the most popular protocols with a dev‑friendly UI, built-in automation, and an extensible plugin ecosystem.

Key Insomnia REST features:

User-Friendly Interface Support for Multiple Protocols Environment Management Custom Plugins and Themes

Open Source

One click public URL for localhost!

Key TunnelPilot features:

Simple Tunnel Setup Developer-Friendly Lightweight Solution Publicly Accessible URLs

OpenApi to Live backend in seconds - Preserving Api State.

Key Stateful Mock API features:

Stateful behavior simulation Quick prototyping and development No infrastructure setup required Realistic CRUD operation mocking

Lightweight container viewer.

Key darklens features:

Simple container management Open source and free Easy deployment Real-time monitoring

Mock APIs that update instantly — no restart, ever.

Key Mocklantis features:

Easy Mock API Creation No Coding Required Fast Prototyping Cloud-Hosted Solution

Generate mock REST APIs in seconds - no backend required.

Key MockMyData.io features:

Easy Mock Data Generation Multiple Data Formats Supported Wide Variety of Data Types No Installation Required

Mock blocked APIs, passthrough ready routes, see live source.

Key Mockphine features:

Quick Mock API Creation No Coding Required Collaboration Friendly Customizable Responses

A fast Desktop API client. Design OpenAPI specs visually. Flow runner. API testing with assertions. Load test. Mock server. atra CLI with CI/CD integration.

freemium $12 / Monthly (Solo User annual)

Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.

Key Proxyman.io features:

User-Friendly Interface Cross-Platform Support Real-time Traffic Interception HTTPS Decryption

Open Source $49 / Annually

Visual API testing that makes multi-step workflows flow — capture values, chain requests, add assertions, schedule runs, and get alerts.

Key FlowTest features:

AI-Powered Testing Low-Code/No-Code Interface Focus on Workflow Testing CLI Integration for CI/CD