Base64URL Encoder and Decoder
Encode text to Base64URL or decode it back. Base64URL is the URL-safe variant from RFC 4648: it swaps the standard plus and slash characters for hyphen and underscore and drops the trailing padding, so the result is safe in URLs, filenames and JWT segments.
How to use the Base64URL encoder
- Choose Encode to convert text to Base64URL, or Decode to read it back.
- Type or paste your input into the box.
- Copy the result, which updates as you type.
Examples
URL-safe encoding
<<???>>
PDw_Pz8-Pg
Decoding back to text
aGVsbG8
hello
Frequently asked questions
How is Base64URL different from standard Base64?
Base64URL, defined in RFC 4648 section 5, uses the same encoding but replaces the two characters that are awkward in URLs: plus becomes hyphen and slash becomes underscore. It also usually omits the equals-sign padding. The decoded bytes are identical to standard Base64.
Why does the output have no equals padding?
Padding only pads the final group to a multiple of four characters and carries no extra information, so most Base64URL uses, including JWTs, drop it. This tool encodes without padding and still decodes correctly whether or not padding is present.
Can it handle emoji and accented characters?
Yes. Input is encoded as UTF-8 first, so accents, emoji and other multi-byte characters round-trip exactly. Decoding reverses the process and returns the original text.
What happens if I paste invalid input when decoding?
Decoding accepts only the Base64URL alphabet of letters, digits, hyphen and underscore. If the input contains other characters, such as a plus or slash from standard Base64, or has an impossible length, the tool reports an error instead of guessing.
Is my data uploaded anywhere?
No. Encoding and decoding run entirely in your browser, so whatever you paste never leaves your device.
Related tools
Base64 Encode
Encode text to Base64 online. UTF-8 safe, handles emoji and accents, with an optional URL-safe (base64url) mode. Runs in your browser, nothing uploaded.
Base64 Decode
Decode Base64 to plain text online. Paste a Base64 or base64url string and get instant UTF-8 output. Free, fast and runs in your browser.
URL Encoder
Encode or decode URLs and query strings online. Percent-encode a value, escape a full URL, or decode back to plain text. Free, fast and private.
.env to JSON
Convert a .env file to JSON, or JSON back to .env. Parses KEY=value lines, comments, quotes and export. Runs entirely in your browser.
ASCII Table
Full ASCII table for all 128 codes with decimal, hex, octal and binary values, character names and descriptions. Search by code, hex or character.
Aspect Ratio Box Generator
Generate CSS for a responsive aspect-ratio container. Use the modern aspect-ratio property or the padding-top fallback, then copy the ready code.