Developer tools

Format JSON, compute hashes, convert dates and colours, test regular expressions.

Format JSONIndent, minify and validate. If it is broken, it says where.Base64Encode and decode, accents included.Hash a file or textMD5, SHA-1, SHA-256 and SHA-512 of a file or text.Read JWTHeader, payload and expiry in plain text.Generate UUIDv4, v7 and ULID, with real randomness.Convert timestampNumber to date and back, without mixing up seconds.Convert coloursHEX, RGB, HSL — and contrast, which is the useful part.Compare textsLine by line, with the differences highlighted.Test regexWith capture groups and the line of every match.Read cronWhat it means, and the next times it fires.Convert YAML and JSONFrom YAML to JSON and back. What JSON cannot express, it tells you.Convert CSV and JSONFrom CSV to JSON and back, without silently changing your data.

Why this section exists

These are the things you do ten times a day and usually end up pasting into the first site that comes up in a search. The flaw in that habit is that the site actually receives what you paste: a production token, the body of a response with customer data in it, the string you are about to put in a config file. Nothing leaves here — and that is the only reason these twelve tools sit on a site of file utilities.

For reading and tidying: JSON formatter, YAML ⇄ JSON, CSV ⇄ JSON and Text diff, which puts two versions side by side and marks what changed. For understanding something before it ships: Regex tester and Cron parser, which turns */15 3 * * 1-5 into a sentence.

For the rest there are Base64, hashes (MD5, SHA-1, SHA-256, SHA-512), UUID, timestamps and colours. One note on the JWT decoder: it shows what a token contains, but it does not verify the signature and never will — that would need your server’s secret key, and a website is not the place to paste it. What you read is what the token claims, not a guarantee that it is true.