Stop Switching Tabs — One Free Tool Replaces All Your JSON & Dev Tools

#webdev #productivity #tooling #codenewbie

Every day I was doing the same thing:

Paste API response into some random formatter
Open another tab to decode the JWT
Open another tab for Base64
Open another tab to test a regex

Four tabs. Same tools. Every single day.

So I built JsonMaster — a free developer toolbox that puts 12 tools in one tab.

👉 https://jsonmaster.netlify.app/

No login. No ads. Your data never leaves your browser.

What's Inside

JSON Formatter & Validator

Paste raw minified JSON and instantly see it beautified. Built on Monaco Editor — the same engine as VS Code — so you get syntax highlighting, inline error squiggles, code folding, and keyboard shortcuts you already know.

JSON Converters

Convert JSON to:

YAML — for Kubernetes, Docker Compose, GitHub Actions
CSV — for Excel, Google Sheets, data pipelines
XML — for legacy systems and SOAP APIs
TypeScript Interface — paste an API response, get a typed interface instantly
Zod Schema — instant runtime validation schema for TypeScript projects
.env file — flatten nested JSON config into environment variables

JWT Decoder

Paste any JWT. See header, payload, signature decoded instantly. Checks expiry and algorithm. Everything happens in your browser — nothing is sent to a server.

Base64 & URL Encoder / Decoder

Encode or decode Base64 and URL strings instantly. Handles Unicode correctly. Useful for decoding auth headers, query strings, and embedded images.

Regex Tester

Write a pattern, test it against your input in real time. Every match is highlighted. Supports all JS regex flags: g, i, m, s, u. Shows match groups and count.

JSON Diff & Compare

Paste two JSON objects. See exactly what was added, removed, or changed — down to the specific key path. Useful for comparing API responses before and after a deploy.