Free Online Developer Tools — All in Your Browser
Format JSON, generate UUIDs, hash text, encode Base64, test regex, and decode JWTs. Every tool runs locally — nothing is sent to a server.
Get Started →All Tools
JSON Formatter
Format, minify, and validate JSON in one place.
UUID Generator
Generate single or batch UUID v4 values.
Hash Generator
Generate SHA-1, SHA-256, and SHA-512 hashes.
Base64 Encode / Decode
Encode text to Base64 or decode Base64 to text.
URL Encoder / Decoder
Encode text for URLs or decode encoded URL values.
Regex Tester
Test regular expressions with live match highlighting and capture group table.
CRON Parser
Parse CRON expressions, describe them in plain language, and preview the next 10 runs.
JWT Tool
Decode, sign, and verify JWT tokens locally.
URL Parser
Break a URL into protocol, host, path, and query parts.
Query String Builder
Build and parse URL query parameters.
Base Converter
Convert integers between bases 2, 8, 10, and 16.
Binary Text Converter
Convert plain text and binary bytes in both directions.
Hex Text Converter
Convert text to hex bytes and decode hex to text.
Every tool runs in your browser. API keys, tokens, and sensitive data never touch a server.
Open any developer tool and start immediately. No extension, no CLI, no setup required.
Every tool is free with no limits, no premium tier, and no usage cap.
No sign-up, no email, no tracking. Just the tool you need, right now.
Frequently Asked Questions
Are my API keys or tokens safe when I use these tools?
Yes. All processing happens entirely in your browser. JWT tokens, API keys, and any other sensitive values you paste are never transmitted over the network.
Do I need to install anything?
No installation is required. Every developer tool runs directly in your browser without extensions, plugins, or local dependencies.
What JSON formatting options are available?
The JSON Formatter supports pretty-printing with configurable indentation, minification to a single line, and syntax validation with detailed error messages for invalid JSON.
What UUID version does the UUID generator produce?
The UUID Generator produces version 4 UUIDs using cryptographically secure random numbers from the browser's Web Crypto API.
Which hash algorithms are supported?
The Hash Generator supports SHA-1, SHA-256, and SHA-512. All hashing is performed locally using the browser's built-in Web Crypto API.
Can I use these tools offline?
Yes. Once the page has loaded, all developer tools work without an internet connection because all processing runs in your browser.
What is Base64 encoding used for?
Base64 encodes binary data as printable ASCII characters. It is used in email attachments, embedding images in CSS or HTML, and encoding API credentials or configuration values.
How do I decode a JWT token?
Paste the JWT into the JWT Decoder and the header, payload, and signature are shown separately. The tool also displays the expiry time and whether the token is currently valid based on its timestamps.
How to format and validate JSON online
Open the JSON Formatter, paste your JSON payload, and the tool automatically formats it with proper indentation and syntax highlighting. If the JSON contains errors, the exact position and reason are shown so you can fix them quickly.
How to generate a UUID online
Open the UUID Generator and click Generate. A cryptographically random UUID v4 appears immediately. For batch generation, specify the count and download all values as a text file or copy them to the clipboard.
How to decode a JWT token
Paste a JWT into the JWT Decoder. The header and payload are decoded and displayed as formatted JSON, and the expiry time is shown in a readable date format. The tool does not verify the signature — for debugging and inspection only.