Developer Tools

Format, validate and diff structured data

Working with APIs means staring at structured text all day. The JSON formatter beautifies, minifies and validates JSON so a one-line API response becomes readable, and the JSON diff viewer highlights exactly which keys and values changed between two payloads. Markup and config get the same treatment with the XML formatter, HTML formatter, CSS formatter, JavaScript formatter and SQL formatter. For arbitrary text, the diff checker shows line-by-line changes between any two snippets.

Encode, decode and inspect

Encoding bugs are everywhere, so the Base64 encoder and decoder and the URL encoder and decoder handle the two most common cases, with bulk URL encode/decode for whole lists and HTML entity encode/decode for markup-safe strings. When you need to read what is inside a token, the JWT decoder splits the header and claims so you can check expiry and audience before trusting it, and the JWT token generator creates signed test tokens. The URL parser breaks a link into its scheme, host, path and query parts.

Convert between data formats

Half of integration work is reshaping data. Move between tabular and tree formats with CSV to JSON and JSON to CSV, between config dialects with JSON to YAML, YAML to JSON and TOML to JSON, and into markup with HTML to JSX for React components. The JSONPath evaluator lets you query a nested object with a path expression rather than scrolling through it by eye.

Generate identifiers and signatures

Need values rather than transformations? The UUID generator produces v4 and other identifiers, the UUID version detector tells you which spec an existing UUID follows, the hash generator and HMAC generator create checksums and signatures, and the Unix timestamp converter turns epoch seconds into a human date and back.

Test, parse and reference

Some tools save you a trip to documentation or a scratch script. The regex tester lets you build and verify a pattern against sample input with live match highlighting, the cron expression parser explains a schedule in plain language, and the user agent parser breaks a UA string into browser, OS and device. Quick lookups live in the HTTP status code reference and the MIME type lookup, while the markdown preview and Tailwind playground give you a quick render surface.

Why client-side dev tools matter

Developer payloads frequently contain secrets - bearer tokens, connection strings, customer records inside a sample response, signing keys. Pasting those into a site that round-trips them through a backend means a third party could log them. Every tool in this category runs as JavaScript in your browser, so the data is processed locally and never uploaded. That also makes the tools fast and usable offline once loaded, which is exactly what you want when debugging on a flaky connection or a locked-down network.

• Local processing - tokens, payloads and keys stay in the tab.
• No signup - paste and go, nothing is saved between sessions.
• Chainable - decode Base64, then format the JSON inside it, then diff it.
• Reference + transform - lookups and converters in one place.