4coders — tiny tools, big grin
Client-side Base64, JWT, JSON, hashes, QR codes & more. Everything runs in your browser — nothing is ever uploaded. Works fully offline.
Press ⌘K to jump anywhere — or pick a tool below.
Free client-side developer tools — nothing ever leaves your browser
Encode / Decode
Base64Encode & decode Base64 — URL-safe, UTF-8 aware.URL / PercentPercent-encode & decode URLs and query strings.HTML EntitiesEscape & unescape HTML entities — no innerHTML.HexText to UTF-8 hex bytes and back.BinaryText to 8-bit binary and back.Unicode Escapes\uXXXX escapes — surrogate-safe.Base32RFC 4648 Base32 encode & decode.ROT13 / CaesarRotate letters by any shift (13 = ROT13).MorseText to Morse code and back.
Inspectors
Hashing
Generators
Barcodes & QR
Why client-side tools?
- • Nothing ever leaves your machine. Paste tokens, secrets or private data with confidence.
- • Works offline after the first load — pull the network cable and keep using every tool.
- • Fast, keyboard-first experience with ⌘K palette, live updates and one-click copy chains.
- • No accounts, no tracking pixels on your inputs, no ads. Just the utilities you need.
Common questions
Do you upload or store anything I paste?
No. Every single conversion, hash, decode and generation runs locally in your browser using Web APIs and small pure-JS libraries.
Can I use 4coders without internet?
Yes — after the page loads once, all tools continue to work offline. Great for air-gapped or restricted environments.
Is this a replacement for CyberChef or jwt.io?
It's a focused, fast, privacy-first subset. If you love small dedicated tools that respect your data, you'll feel at home here.