9 Postman Alternatives (2026)

API Interceptor, Mocker and Tester

Intercept modify and mock HTTP requests with ease

Intercept, modify, and mock HTTP requests with ease. This powerful developer tool helps you streamline your API development and testing workflow by giving you full control over network traffic. You can use it to test how your application handles different data responses without needing to change...

Voiden - Your API work, but done better

Working with APIs in your flow, plain markdown. Open Source.

Voiden is an offline API client that helps developers and QA folks design, test, document APIs, in one place, in plain text executable files. Unlike legacy API tools, Voiden does not force you in a fixed interface. Instead it lets you compose APIs with blocks (headers, auth, params, body). Reuse...

Owlpost

Desktop client for testing Protobuf and gRPC APIs

**The problem:** Testing gRPC and Protobuf-based APIs is painful compared to REST. Most API clients (Postman, Insomnia, etc.) were built REST-first, so gRPC support is either missing or bolted on as an afterthought. Backend engineers end up falling back to grpcurl in a terminal - manually...

Routebase

Your API drifts across several tools. Routebase fixes it.

Your API doesn't really live in one place. It lives in your design tool, your docs, your mocks, your tests, and your monitoring - and every copy drifts on its own schedule: stale docs, broken mocks, tests that lie. That drift is where the bugs live, and no point tool fixes it, because the pain...

SynthAPI

Realistic mock APIs for builders

I kept running into the same bottleneck on almost every project: the UI is ready to go, but the backend API isn’t finished yet. Hardcoding mock data or using basic static JSON generators gets messy quickly, especially when you need to test real-world edge cases like rate-limiting, network latency...

VReq API Runner Verified

File-based API testing in VS Code

VReq is a Visual Studio Code extension designed for file-based API testing. It allows developers to manage scenarios and environments directly within their workspace using dedicated .vreq, .venv, .vscript, and .vscenario file formats.

JsonXmlEditor

Native JSON and XML editor and linter for macOS

JsonXmlEditor is a native macOS application designed for developers working with structured data. It enables side-by-side editing of JSON and XML files, providing built-in linting for payload validation. Beyond simple editing, the tool allows you to run REST requests, generate DTOs directly from...

Postmate Client

Privacy-first Postman alternative in VS Code, zero cloud

Postmate Client is a free, privacy-first API client that lives entirely inside VS Code - a true Postman alternative for developers who want powerful API testing without cloud sync, forced logins, or telemetry. Everything runs locally. Your collections, environments, and test data are stored as...

Roley

Build, test, and document APIs in one fast workspace

Roley is an all-in-one API development platform that helps developers and teams build, test, document, monitor, and collaborate on APIs from a single unified workspace. Designed as a powerful alternative to Postman, Roley offers familiar Postman-style workflows, making API management faster...