Useful tools, right in your browser
Developer tools
Choose a published tool for your task. Files and text are processed in this browser; each tool lists its limits and actual output.
Developer tools
5 tools available
- Local processing
JSON formatter and validator
Format, compact and check JSON while preserving large numbers and duplicate keys.
Developer tools - Local processing
Number base converter
Convert signed integers exactly between bases 2–36, including binary, octal, decimal and hexadecimal.
Developer tools - Local processing
CSV / JSON converter
Convert local CSV tables and string-only JSON without changing long IDs or leading zeroes.
Developer tools - Local processing
Color picker and contrast
Pick image colors, convert HEX/RGB/HSL and check text contrast.
Developer tools - Local processing
Encoding and decoding
Encode or decode URL components, full URIs and UTF-8 Base64.
Developer tools
New to image tools?
Learn how file size, pixel dimensions and encoding quality differ.
Get started
- Choose a tool from the directory.
- Open its page and set the options for your task.
- Review the result before downloading or using it.
Keep control of your files
Published tools process your files or text in this browser. You choose when to copy or download the result. No account or input upload is required.
Choose a useful result
Each tool explains its supported inputs and limits. A file size target is not a guarantee; compare the actual result and keep your original.
About these tools
Are my files uploaded?
The tools work locally and do not send files, filenames, text or results to a server. Loading these pages still requests ordinary static website resources.
Can I use another language?
English, simplified Chinese, traditional Chinese and Japanese have fixed page addresses. A language switch keeps the same tool or content where that translation is available.
Do I need an account?
No. Open a tool and use it directly. You can choose whether to save a manual language preference; optional services and their storage are explained on the privacy page.