Developer Tools

JSON, Base64 and URL utilities that run locally — your data never leaves the page. Every tool runs in your browser — nothing is uploaded.

All developer tools

13 tools

JSON FormatterFormat and indent JSON, or minify it. Invalid JSON gets an error that points at the problem. Free, i… JSON ValidatorCheck whether JSON is valid, and get the exact position and likely cause when it is not. Free, insta… JSON to CSV ConverterTurn an array of JSON objects into CSV, ready for a spreadsheet. Free, instant, runs entirely in you… Base64 Encoder and DecoderEncode text to Base64 or decode Base64 back to text, with full Unicode support. Free, instant, runs … URL Encoder and DecoderPercent-encode text for URLs, or decode an encoded URL back to readable text. Free, instant, runs en… Hash GeneratorGenerate MD5, SHA-1 and SHA-256 hashes of any text, computed in your browser. Free, instant, runs en… UUID GeneratorGenerate version 4 UUIDs in bulk, using your browser’s cryptographic random number generator. Free, … Color ConverterConvert between HEX, RGB and HSL, and see the WCAG contrast ratio against white and black. Free, ins… Unix Timestamp ConverterConvert a Unix timestamp to a readable date, or a date back to a timestamp, in seconds and milliseco… JWT DecoderDecode a JSON Web Token to read its header and payload, and see whether it has expired. Free, instan… CSV to JSONConvert CSV into JSON, handling quoted fields, escaped quotes and commas inside values properly. Fre… JSON to YAMLConvert JSON into YAML, with the quoting rules that stop YAML reading your values as the wrong type.… Cron Expression ExplainerRead a cron expression in plain English and see exactly when it will next run. Free, instant, runs e…

About these tools

JSON, Base64 and URL utilities that run locally — your data never leaves the page. They share a small number of engines configured differently on each page — a target file size, and where a form demands it, exact pixel dimensions. The result is tuned to the specification you actually need to meet, rather than a generic "make it smaller" pass.

Processing happens on your device. Your files are never uploaded to a server, which is why there are no usage limits and no account to create.

Frequently asked questions

What developer tools are on this site?

There are 13 in this category: JSON Formatter, JSON Validator, JSON to CSV Converter, Base64 Encoder and Decoder, URL Encoder and Decoder, Hash Generator, and 7 more. JSON, Base64 and URL utilities that run locally — your data never leaves the page.

Are the developer tools free to use?

Yes. No account, no trial, no watermark and no cap on how many files you process. Every setting is available to everyone.

Do my files get uploaded?

No. These tools run entirely in your browser, so the file never leaves your device. You can confirm it in your browser’s Network tab, or by disconnecting from the internet once the page has loaded — the tools keep working.

Do I need to install anything?

No. There is nothing to download and no extension to install. Open the tool you need and use it.

Is it safe to paste API responses or tokens here?

The processing happens in your browser and nothing is transmitted, which is exactly why these tools exist as local ones. That said, a live token is a credential: prefer an expired or test value where you can.