Encode and decode Base64, URLs, HTML entities, Unicode, JWTs and classical ciphers. Encoding makes data safe to transport; it is not encryption and it is not hashing — anything encoded here can be decoded by anyone. Everything runs locally in your browser.
Base Encoding Tools
- Base64 Encoder
Convert text or Unicode characters into Base64 – the binary-to-text encoding used by email attachments, data URIs and HTTP basic authentication.
- Base64 Decoder
Decode a Base64 string back to readable text, with clear errors for invalid characters, wrong length and bad padding.
- Base64URL Encoder
Encode text with the URL-safe Base64 alphabet from RFC 4648 section 5: minus and underscore replace plus and slash, and padding is normally dropped, so the result is safe in URLs, filenames and JWTs.
- Base64URL Decoder
Decode URL-safe Base64 – the variant used in JWT header and payload sections – back to text, handling missing padding automatically.
- Base32 Encoder
Encode data as Base32 (RFC 4648) using the case-insensitive A-Z 2-7 alphabet found in TOTP authenticator secrets, DNS records and Onion addresses.
- Base32 Decoder
Decode Base32 back to text or bytes.
- Base58 Encoder
Encode bytes as Base58 – the Bitcoin alphabet that deliberately omits 0, O, I and l so codes survive being read aloud, handwritten or retyped.
- Base58 Decoder
Decode a Base58 string such as a Bitcoin address or IPFS CIDv0 back to its underlying bytes, shown as text where possible and hex otherwise.
- Ascii85 Encoder
Encode data as Ascii85 (base85), which packs 4 bytes into 5 characters for about 25 percent overhead versus the 33 percent of Base64.
- Ascii85 Decoder
Decode Ascii85 or base85 data back to bytes, accepting the Adobe delimiters and the z shortcut that stands for four zero bytes.
URL and Web Encoding Tools
- URL Encoder
Percent-encode a URL or a single value.
- URL Decoder
Decode percent-encoded URLs back to readable text, with an optional plus-as-space rule and a repeat mode that unwraps double-encoded values such as %253A.
- URI Component Encoder
Escape a single URI component – a query value, path segment or fragment – so reserved characters like ampersand, equals, question mark, slash and hash cannot break the surrounding URL.
- URI Component Decoder
Decode a single percent-encoded URI component back to its original value, treating the plus sign as a space by default as HTML form submissions do.
- Query String Parser
Split a URL query string into readable key and value pairs or JSON, decoding percent-escapes and plus signs, and flagging repeated parameters whose handling differs between servers.
- Query String Builder
Turn key and value lines or a JSON object into a correctly escaped query string, with repeated keys for array values and optional RFC 3986 strict escaping.
- HTML Entity Encoder
Convert characters into HTML entities so markup displays as text instead of being parsed.
- HTML Entity Decoder
Turn HTML entities back into characters – named, decimal and hexadecimal – with a repeat mode for text that was escaped twice.
- XML Entity Encoder
Escape text for XML, which predefines only amp, lt, gt, quot and apos – everything else must be a numeric reference.
- XML Entity Decoder
Decode XML entities back to text.
- Punycode Encoder
Convert an internationalized domain name to its ASCII xn-- form using RFC 3492 Punycode, so non-Latin domains work in DNS.
- Punycode Decoder
Turn xn-- domain labels back into readable Unicode, and flag mixed-script labels that may be homograph lookalike domains used in phishing.
Text and Character Encoding Tools
- Text to Binary
Convert text into binary – eight bits per UTF-8 byte, or one number per Unicode code point.
- Binary to Text
Convert binary numbers back into readable text.
- Text to Hex
Convert text to hexadecimal – two hex digits per UTF-8 byte, or per code point.
- Hex to Text
Convert hexadecimal back to text, accepting spaces, commas, colons and 0x prefixes, and warning when the bytes decode to something other than clean UTF-8.
- Text to ASCII
Convert text to ASCII character codes in decimal, hex, binary or octal, with strict validation because ASCII defines only the 128 characters numbered 0 to 127.
- ASCII to Text
Turn ASCII character codes back into text, with an option to name control characters such as LF and TAB instead of printing invisible bytes.
- Text to Decimal
Convert text into decimal numbers – full Unicode code points by default, so an emoji becomes a single number such as 128512 rather than several byte fragments.
- Decimal to Text
Convert decimal numbers back into characters, treating them as Unicode code points or as raw UTF-8 bytes, with clear errors for surrogates and out-of-range values.
- Text to Octal
Convert text into octal, base 8, at three digits per byte.
- Octal to Text
Convert octal numbers back into readable text, validating that every digit falls in the range 0 to 7.
- Unicode Escape
Turn characters into escape sequences for JavaScript, ES6, CSS, Python, Java or C, which is useful when source files or config formats must stay pure ASCII.
- Unicode Unescape
Convert escape sequences in the JavaScript, ES6, Python and hex styles back into the characters they represent, flagging unpaired surrogates.
- Unicode Code Point Converter
Look up the code point of every character – with its decimal value, UTF-8 bytes and UTF-16 units – or turn U+ notation back into text.
- UTF-8 Encoder and Decoder
Inspect exactly how text becomes UTF-8 bytes – as hex, percent-escapes, decimal or hex escapes – and convert those bytes back to text.
- UTF-8 Byte Counter
Count UTF-8 bytes, characters and UTF-16 units separately – the three numbers that disagree whenever emoji or non-Latin scripts appear – and compare them against common limits.
- Character Encoding Detector
Analyse bytes for a byte order mark, ASCII-only content, valid UTF-8 and classic mojibake patterns, separating what can be proven from what can only be guessed.
Cipher and Communication Tools
- ROT13 Encoder and Decoder
Apply ROT13, ROT13.
- Caesar Cipher Encoder and Decoder
Shift letters by any amount from 1 to 25, or break an unknown Caesar cipher instantly by showing all 25 possible shifts at once.
- Atbash Cipher
Apply the Atbash substitution, which mirrors the alphabet so A becomes Z and B becomes Y.
- Vigenere Cipher Encoder and Decoder
Encrypt or decrypt with a repeating keyword, the classic polyalphabetic cipher.
- Morse Code Translator
Translate text to international Morse code and back, covering letters, digits and common punctuation, with configurable word separators.
- NATO Phonetic Alphabet Converter
Spell text out in the ICAO and NATO phonetic alphabet – Alfa, Bravo, Charlie – for reading codes aloud over phone or radio, and convert phonetic words back to text.
- Quoted-Printable Encoder
Encode text as quoted-printable (RFC 2045), the email transfer encoding that keeps mostly-ASCII text readable while escaping everything else.
- Quoted-Printable Decoder
Decode a quoted-printable email body back to readable text, resolving the escapes and removing soft line breaks.
- MIME Header Encoder and Decoder
Decode encoded words from email Subject and From headers, or build your own – the RFC 2047 mechanism that lets ASCII-only headers carry any language.
JWT and Token Tools
- JWT Decoder
Decode a JSON Web Token to inspect its header and payload, with registered claims explained and timestamps converted to dates.
- JWT Structure Validator
Check a JWT for structural problems – section count, Base64URL validity, JSON shape, the required alg field, claim types, expiry and the dangerous alg none case.
- JWT Encoder
Build and sign a demonstration JWT locally with HS256, HS384 or HS512.
