String Encoder/Decoder

A free, fast, offline, multi-language workbench for text encoding, decoding and hashing.

Paste something in, pick a transform, and the result appears as you type. No ads, no accounts, no network calls — your text never leaves your phone.

TWENTY-FIVE TRANSFORMS

Encodings: Base64 (standard and URL-safe), Base32, Base58, hexadecimal, binary, decimal bytes, octal, URL percent-encoding, HTML entities, Unicode escapes, JSON string escaping, quoted-printable, Ascii85, and gzip.

Ciphers: Morse code, NATO phonetic alphabet, A1Z26, ROT13, ROT47, Caesar shift, Atbash, and Vigenere.

Text: reverse, case conversion (UPPER, lower, Title, Sentence, snake_case, kebab-case, camelCase, aLtErNaTiNg), and line sorting with duplicate removal.

Crypto: an AES-256-GCM vault with PBKDF2 key derivation at 200,000 rounds.

CHAIN THEM TOGETHER

Wire several transforms into one signal path — gzip, then AES, then Base64 — and String Encoder/Decoder runs them in order. Switch to Decode and it runs the whole chain backwards automatically, so you never have to think about the reverse order.

DETECT WHAT YOU PASTED

Not sure what you are looking at? Tap Detect. String Encoder/Decoder inspects the text, picks the matching decoder and flips to Decode for you.

FINGERPRINTS AND ANALYSIS

Get MD5, SHA-1, SHA-256, SHA-384, SHA-512 and CRC32 for any message, in lowercase or uppercase, each with a one-tap copy. Alongside them: character, byte, word, line and unique-character counts, longest line, and Shannon entropy — a quick read on whether data is plain text or already encoded.

BUILT FOR REAL WORK

- Open a .txt, .json, .csv, .md or .log file straight into the editor

- Copy, share or export the result as a text file

- Feed the result back into the source with one tap to keep transforming

- Save any setup to your library; the source, chain and direction all come back together

- Every error explains exactly what went wrong — which character broke it, which padding is missing

MADE TO LOOK AT

Nine themes, from the default Obsidian to Blueprint, Terminal, Papyrus, Frost, Amber CRT, Magenta Void, Graphite and Moss. Pick your data font from JetBrains Mono, IBM Plex Mono, Space Mono, Space Grotesk or your system monospace. Everything is laid out for one-handed use, with settings tucked into bottom sheets so the workbench stays clear.

WHO IT IS FOR

Developers debugging API payloads and JWT fragments. Students working through classical ciphers. Sysadmins decoding log entries. Anyone who has ever needed to turn one string into another and did not want to paste sensitive data into a website.

Works fully offline.