Documentation
FormatTools is a suite of developer utilities that run entirely in your browser — nothing you paste into any tool is ever sent to a server. This page covers what's available and how the site works.
How it works
Every tool — formatting, validating, converting, diffing, decoding — runs as JavaScript in your browser. There's no account, no sign-up, and no server-side processing of anything you paste in. For large inputs (roughly 200KB and up), the work moves to a Web Worker so the tab stays responsive instead of freezing while it processes.
Keyboard shortcuts
- Ctrl / Cmd + K — opens a search palette to jump straight to any tool below, from any page.
- Esc — closes whatever overlay is currently open (the search palette, a header dropdown, or the mobile menu).
Available tools
JSON Tools
- JSON Formatter — Make messy, minified JSON readable with customizable indentation.
- JSON Beautifier — Pretty-print JSON with the same fast, local engine.
- JSON Validator — Check JSON validity with precise line/column errors.
- JSON Viewer — Explore JSON as a collapsible, searchable tree.
- JSON Minifier — Strip whitespace to compress JSON for transport.
- JSON Compare — Diff two JSON documents and highlight the changes.
- JSON to CSV — Flatten nested JSON into a downloadable CSV file.
Base64 Tools
- Base64 Encode — Encode plain text to Base64 instantly in your browser.
- Base64 Decoder — Decode Base64 text back to readable Unicode instantly.
URL Tools
- URL Encoder — Safely percent-encode text for use in URLs and query strings.
- URL Decode — Decode percent-encoded URLs back to readable text.
YAML Tools
- JSON to YAML — Convert JSON documents to clean, indented YAML.
- YAML to JSON — Convert YAML configs back to structured JSON.
XML Tools
- JSON to XML — Convert JSON into well-formed XML markup.
- XML to JSON — Convert XML documents into structured JSON.
JWT Tools
- JWT Decoder — Inspect JWT header, payload, and signature with syntax highlighting.