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DevTools24

About DevTools24

DevTools24 is a collection of small, focused tools for developers, testers and anyone who works with data: formatting and comparing JSON, converting images, and reading and checking JSON Web Tokens.

Why it exists

Many online tools ask you to upload your files or paste your data into a form that goes to someone else's server. That is a poor fit for API responses, config files, private photos or security tokens. Every tool here runs inside your browser instead, so your data never leaves your device. You do not need an account. The site is free because it shows ads, which never see what you put into the tools.

The tools

  • JSON Formatter and Validator: Format, minify and validate JSON with clear error messages.
  • JSON Compare: See what was added, removed or changed between two JSON documents.
  • Image Converter: Convert up to 15 images at once between JPG, PNG, WebP, AVIF, HEIC, GIF, TIFF, ICO and more.
  • JWT Decoder and Verifier: Decode, verify and create JSON Web Tokens without sending them anywhere.
  • Image Resizer: Resize images to an exact size, by percent or for social media, and keep files under a size limit.
  • Image Cropper: Crop images with a free or fixed shape, rotate and flip them, or cut a circle.
  • Background Remover: Remove an image background on your own device and download a transparent PNG.
  • API Client: Send HTTP requests and read responses, with collections, environments and Postman import.
  • JSON to Code: Turn JSON into model classes for Kotlin, Java, TypeScript, Dart, Swift, C#, Python, Go, Rust, PHP and Ruby.
  • Data Converter: Convert between JSON, YAML, XML and CSV, in either direction.
  • XML Formatter and Validator: Format, minify and validate XML, keeping comments, CDATA and attributes as written.
  • YAML Validator and Formatter: Check YAML for mistakes and format it, with errors shown by line.
  • App Icon Generator: Create every Android and iOS app icon size from one image, ready for your project.

More tools are on the way for mobile developers, such as turning JSON into Kotlin, Dart or Swift models and generating app icons.

Who builds it

DevTools24 is built and run by an independent developer. The source code is public on GitHub, so you can see exactly what the tools do with your data. The open source libraries it uses are listed with their licences in third-party-licenses.txt.

Feedback

Found a bug or missing a tool? Say so on the contact page. Requests from people who use the tools decide what gets built next.