JSON Fmt

Small developer tools that run in your browser and send nothing anywhere.

JSON Fmt is a set of developer utilities that do one job each: format or validate JSON, encode and decode Base64 and URLs, convert Unix timestamps, hash a string, test a regular expression. Each page loads fast, has no sign-up, and keeps your data on your machine: the code runs in the browser and the page makes no network requests with what you paste.

They are written by a working engineer for the moments when you have a blob of JSON from a log, a token from a header or a timestamp from a database and want to see it properly without installing anything or trusting a random site with the contents.

Every page explains what the tool does under the hood and the edge cases that catch people out, so it is also a short reference.

Tools

• Base64 and URL encoderEncode or decode Base64 (UTF-8 safe) and URL-encode or decode text, in the browser, with a note on what each encoding is for.
• JSON formatter and validatorPretty-print, minify or validate JSON in the browser, with the line and column of the first error and an option to sort keys.

Who makes this

JSON Fmt is written and kept by ABSU Mobilities, Hyderabad. Every tool page says how it calculates, shows a worked example, and lists its sources with the date they were read. If a number looks wrong, tell us.