About Formattr

What it is

Formattr has 46 tools for JSON, YAML, XML, CSV, SQL, code, text, dates and numbers, and a universal formatter that recognizes what you paste. Every tool shares one editor, so the output of one becomes the input of the next: format JSON, convert it to YAML, minify it, and step back through the chain without pasting twice.

Principles

• Nothing is uploaded. All processing happens in your browser, in an isolated frame that cannot make network requests. The privacy page explains how, and how to check.
• Reference formatters. Code is formatted with the tools your editor uses — Prettier, clang-format, gofmt and Ruff — so the output matches what a review check expects.
• Exact errors. Invalid input gets a line, a column, a likely cause in plain language and, where it is safe, a one-click fix.
• Calm by default. No sign-up, no interstitials, no pop-ups over the editor. Ads, where they appear, stay below the workspace.
• Your settings stay. Indent, dialect, keyword case and the rest are remembered per tool on your device.

What Formattr does not do

Formattr is about the structure and presentation of content: beautify, minify, validate, convert and normalize. It deliberately leaves out diffing, regex testing, cron expressions, sorting or deduplicating lines, and HTTP debugging. Keeping the scope narrow is what keeps each tool fast and dependable.

Contact

Questions, bug reports and format requests go to hello@formattr.com. See the contact page for what helps us reproduce a problem.