The developer’s pocket knife

JSON, Base64, hashes, JWTs, regex, cron and colours — instant, ad-light and 100% client-side, so it is safe to paste real data.

🔒 Runs 100% in your browser — safe for real data

Data & encoding

JSON formatter & validatorBeautify, validate & minify JSON.JSON to CSV converterJSON arrays → CSV for Excel/Sheets.Base64 encoder & decoderEncode/decode text, UTF-8 & URL-safe.URL encoder & decoderPercent-encode, decode & parse URLs.HTML entity encoder & decoderEscape & unescape HTML entities.

Security

Hash generator (MD5, SHA-256…)MD5, SHA-1, SHA-256, SHA-512 for text & files.JWT decoderDecode header, payload & expiry.

Text & code

Regex testerLive matches, groups & replace.Cron expression explainerCron in plain English + next runs.Unix timestamp converterEpoch ↔ human date, live clock.

Design

Color converter & paletteHEX ↔ RGB ↔ HSL, contrast & palettes.CSS gradient generatorVisual linear/radial/conic gradients.

More variants

Why DevKnife?

Pasting a production JWT or customer JSON into a random website is a security risk. Every DevKnife tool runs locally — open your browser’s network tab and you will see nothing is sent. Pages are static, tiny and load instantly.