Cost / License
- Free
- Open Source
Application types
Platforms
- Python
- BSD
- Linux
- Mac
- Windows

Assertible is described as 'The easiest way to test and monitor your APIs and helps reduce bugs in web apps by providing tools to continuously validate endpoints and responses with a flexible interface to run your tests any time and place' and is a HTTP Client in the development category. There are more than 50 alternatives to Assertible for a variety of platforms, including Mac, Linux, Windows, Web-based and SaaS apps. The best Assertible alternative is Postman, which is free. Other great apps like Assertible are Insomnia REST Client, Yaak, Hoppscotch and Cartero.

This is a tool to manually explore and test HTTP REST webservices. Runs queries from a plain-text query sheet, displays results as a pretty-printed XML, JSON and even images.

We alert you, before your customers do.
OnlineOrNot monitors your websites, web apps, and APIs, letting you know instantly if anything goes wrong.


Httpiness is aimed to be a simple, straightforward HTTP client which minimizes time to configure, send, reconfigure and resend requests in order to maximize development efficiency.


RESTClient can be used to test variety of HTTP communications and RESTful webservices. Friendly GUI, rich functionalities.



HTTP client plugin for Sublime Text with an expansive feature set, modern UX, elegant syntax and first class support for testing.




API Test Base is a free tool for integration testing a variety of APIs. It is suitable for Integration, ESB and Microservices testing.






Lama2 defines the human-friendly l2 syntax and CLI for describing and executing APIs. Store your APIs in plain-text files. Collaborate with team using version control (say, git). Run Lama2 directly from VSCode extension. Think of Lama2 as Markdown for APIs.




Silent Down is a website uptime and performance monitoring platform, to keep an eye on your application and instantly alert you if any issues arrive.




Bearer is a developer tool that helps engineering teams monitor API requests, track performance, detect anomalies, and fix issues for their critical API usage. The solution monitors all outgoing API requests without proxying traffic.



