Free Online Encoding & Decoding Tools
Encode and decode without leaking your data
Encoding is the plumbing of the web. Base64 carries binary through JSON APIs and HTTP headers, percent-encoding makes URLs safe, HTML entity encoding lets code be displayed as text instead of executed as markup, and data URLs embed files inline. Getting these transformations right — including the URL-safe variants, the escaping edge cases, and the difference between encoding and encryption — is the difference between working code and a subtle bug. The tools in this category handle those transformations correctly and entirely inside your browser.
All Encoding & Decoding Tools
Base64
Encode and decode Base64 strings online. Supports UTF-8 text and URL-safe Base64. All processing runs locally in your browser.
Base32
Encode and decode Base32 strings online (RFC 4648). Handles TOTP / Google Authenticator secrets, DNSSEC records, and other case-insensitive binary-to-text formats. 100% local.
Base58
Encode and decode Base58 strings online — the alphabet used by Bitcoin addresses, Solana public keys, IPFS CID v0, and Flickr short links. 100% local, no padding, human-safe.
Punycode
Convert internationalized (IDN) domain names to and from their ASCII xn-- form. Follows RFC 3492 exactly — the same encoding your browser and DNS resolver use. 100% local.
Unicode Escape
Escape and unescape Unicode sequences online. Convert any text to \uXXXX / \u{XXXX} form, or reverse escape sequences back to readable text. Handles surrogate pairs and emoji. 100% local.
URL Encode/Decode
Percent-encode and decode URLs online. Handles query strings, path segments, and special characters correctly.
HTML Encode/Decode
Encode and decode HTML entities (&, <, >, ", numeric references). Useful for sanitizing user content or debugging escaped markup.
ROT13
Apply ROT13 to any text online — a symmetric letter-rotation cipher (rot13(rot13(x)) == x). Also supports ROT-N with custom shift, and ROT47 for full ASCII coverage. Runs 100% locally.
Image → Base64
Convert images to Base64 data URLs online. Drop or select any image and copy the ready-to-paste data URI for CSS, HTML, or JSON.
Base64 Image Decoder
Decode Base64 strings back to images. Paste a data:image/... string or raw Base64, and see the decoded image instantly. Useful for debugging data URIs and embedded images. 100% local.
When to use these tools
Use these tools when embedding binary in text-based formats, sanitizing user content for display, decoding a Basic Auth or JWT segment, or debugging why a URL parameter looks garbled after a round-trip.
Frequently Asked Questions
Is encoding the same as encryption?
No. Encoding (Base64, URL, HTML entity) transforms data into a different representation but is fully reversible without a secret. Never use encoding to hide sensitive information.
When should I use URL-safe Base64?
Use URL-safe Base64 whenever the output will appear inside a URL, filename, or a JWT segment. It replaces `+` and `/` with `-` and `_` so no further percent-encoding is required.