Developer tools
JSON Formatter
Validate and pretty-print JSON.
Base64 Encode / Decode
Convert text to and from Base64.
Hash Generator
Generate SHA-1, SHA-256, SHA-512 hashes.
UUID Generator
Generate RFC-4122 v4 UUIDs.
URL Encode / Decode
Percent-encode strings and URLs.
Regex Tester
Test regex patterns with live highlighting.
Markdown Previewer
Live-render Markdown as you type.
CSS Minifier
Strip whitespace and comments from CSS.
JS Minifier
Light cleanup for smaller JS files.
Timestamp Converter
Convert Unix epoch time to a date, and back.
JWT Decoder
Decode a JSON Web Token's claims.
Cron Expression Generator
Build a cron schedule visually.
CSV to JSON Converter
Convert CSV or TSV data to a JSON array.
JSON to CSV Converter
Convert a JSON array to CSV.
Markdown Table Generator
Turn CSV or spreadsheet data into a Markdown table.
JSON Diff Checker
Compare two JSON values and see what changed.
URL Parameter Parser
Break a URL into its parts and parameters.
User Agent Parser
Parse a browser's user agent string.
Open Graph Preview Tool
Preview how a link will look when shared.
Common uses
- Validating and pretty-printing an API response
- Generating UUIDs for test fixtures or database seeding
- Checking a regex pattern against real sample text before shipping it
- Decoding a Base64 string from a bug report or JWT payload
- Previewing how a README will render before committing it
How to choose
Most of these tools solve a task specific enough that there's little overlap — the trick is knowing which one exists for a problem you already have. Debugging a malformed API payload or config file: JSON Formatter. Decoding a JWT segment or a Base64 blob from a bug report: Base64 Encode/Decode. Verifying a file's integrity or generating a checksum: Hash Generator (SHA-1, SHA-256, SHA-512 — avoid SHA-1 for anything security-sensitive, it's included mainly for legacy compatibility checks). Needing unique identifiers for test data or a database schema: UUID Generator. Building or debugging a URL with special characters: URL Encode/Decode. Working out whether a regex pattern actually matches what you think it matches, with live highlighting instead of trial-and-error in your editor: Regex Tester. Checking Markdown rendering before a commit: Markdown Previewer. Shrinking a stylesheet or script for production: CSS Minifier or JS Minifier, respectively.
Frequently asked questions
No. All parsing, hashing, and encoding happens locally in your browser — nothing is transmitted or logged.
Yes, it uses your browser's native JSON.parse, so error messages match exactly what your own code will see.
Yes — hashing uses the Web Crypto API (SubtleCrypto), the same engine built into modern browsers, supporting SHA-1, SHA-256, and SHA-512.