18 Free Useful Online Tools for Web Developers

18 Free Useful Online Tools for Web Developers

Here is a compilation list of the best online tools for web development. These are useful web-based tools that developers can use for their testing, debugging, development, and documentation.  All of the tools that are listed falls in these categories: Live Web Applications with no extension or apps that you should host; free to use or offers free plan; and are useful for many platforms.

online tools for web developers

Feed validator

W3C’s feed validation service which checks the syntax of RSS and ATOM syndicated feeds.


WebSocket Echo Test

Let’s you test a WebSocket connection from your browser against their WebSocket echo server.



It uses an expressive SQL-like language which allows you filter, query, and join data across Web services.


Yahoo Pipes

It supports a graphical user interface which you can use for aggregating, manipulating, and mashing up contents from around the web.



It provides way to generate REST API documentation with organized around resources, code samples and easy to explore.

Similar tools: Swagger.


Pingdom Full page test

The tools helps you analyze the load speed of your websites and learn how you can make them faster.

Similar tools: Web page test.


HAR viewer

This online tool visualizes HTTP Archive (HAR) log files created by HTTP tracking tools.


CORS proxy

The tool allows Javascript code on your website to access resources on on other domains that normally be blocked because of the same-origin policy.



The tool offers interactive cross-browser testing using all major browsers and versions.



It lets you create a URL that will collect requests that are made to it, from there, you can inspect them in a human-friendly way.



This tool makes HTTP requests. You can use it by entering a URL, setting some headers, viewing the response, and then sharing it with others. It is perfect for demoing and debugging APIs.

Similar tools: REST test test, Apigee console.



httpbin offers HTTP Request and Response Service.

Similar tools: UrlEcho.



REDbot is a robot that can check HTTP resources and see how they will behave. It also points out common problems and suggest improvements.

Similar tools: HTTP lint.


Link checker

Link checker tool looks for issues in links, anchors and referenced objects in a web page, CSS, or on a whole web site.


Host tracker

HostTracker tool is a website monitoring service useful for monitoring network and site maintenance.

Similar tools: Down for everyone or just me, Pingdom ping service.



WebGun is an online tool where you can add webhoocks to you app. WebGun API is useful for managing, delivering, and tracking webhooks effortlessly.

Similar tools: UrlReq.



This tools converts data in existing HTML site and Wikipedia pages to JSON APIs. The APIs can be consumed from Ruby, Python, PHP, Node.js, iPhone and Android apps.



Unicorn is W3C’s unified validator useful in improving the quality of a website.

Similar tools: HTML lint.

That’s it! Know some more free useful online tools for web developers that we haven’t mentioned? Come and share it with us.