W3C Markup Validation Service
HTML Validator
Total Validator
PageSpeed Insights
Rocket Validator
GTmetrix
Nibbler
Scrutiny
CodeSandbox
CodePen
replit
JSFiddle
StackBlitz
GitHub
Visual Studio Code
JS Bin
W3C Markup Validation Service CodeSandboxBased on our record, CodeSandbox should be more popular than W3C Markup Validation Service. It has been mentiond 300 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Validate Your Code Include tools like W3C code validation service and CSS validator to ensure your code meets web standards. - Source: dev.to / about 1 month ago
===> Click here to run your code through the HTML validator. - Source: dev.to / 5 months ago
Try looking at tools like https://validator.w3.org/. Source: 5 months ago
I'm looking for either that specific validator (older version of https://validator.w3.org/) or an equivalent that can validate pre-HTML5 (DTD-based) files in a similar fashion. I would appreciate any pointers in the right direction. Thanks in advance. Source: 11 months ago
Not an addon, but maybe it helps Https://validator.w3.org/. Source: 11 months ago
Ok last but not least, Codesandbox. This is a newcomer to online collaborative workspaces which seems much more advanced. Codesandbox.io allows you to create node/npm projects, install packages, setup webpack or bundlers, include frameworks like React or Vue, and code in Typescript or JavaScript. It looks and acts like an IDE (VSCode) in the cloud, allowing shareable projects, not just code snippets. - Source: dev.to / about 2 months ago
Codesandbox.io — Online Playground for React, Vue, Angular, Preact, and more. - Source: dev.to / 3 months ago
Sync your projects effortlessly with GitHub. Codesandbox. - Source: dev.to / 3 months ago
Use online code editors such as Codesandbox or Stackblitz. They let you focus on writing code rather than dealing with local environment complexities. - Source: dev.to / 3 months ago
For this article, I will be using an online code editor called Codesandbox. You can go ahead and use it as well, you can also create normal React js application on your computer. - Source: dev.to / 4 months ago
HTML Validator - HTML Validator is a Mozilla extension that adds HTML validation inside Firefox and Mozilla.
CodePen - A front end web development playground.
Total Validator - Total Validator can check your website to help ensure that it is accessible, uses valid HTML and CSS, has no broken links, and is free from spelling mistakes.
replit - Code, create, andlearn together. Use our free, collaborative, in-browser IDE to code in 50+ languages — without spending a second on setup.
PageSpeed Insights - PageSpeed is addon for ...
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.