Base64URL Encoder / Decoder

Encoded 5 character(s) of UTF-8 text to 7 URL-safe Base64 character(s).

How it works

• Read the input as UTF-8 bytes.
• Grouped the bytes in threes and mapped each group to four characters from the URL-safe alphabet (A-Z, a-z, 0-9, -, _).
• Omitted the '=' padding so the value is directly usable in a URL or JWT segment.

• Base64URL is an encoding, not encryption; it provides no confidentiality.
• The tool accepts both padded and unpadded input so JWT segments decode directly.

Methodology

1. Encode by grouping UTF-8 bytes in threes and mapping each group to four six-bit characters from the URL-safe alphabet.
2. Decode by reversing that mapping, restoring any omitted padding, and rejecting characters outside the alphabet.
3. Treat the result as an encoding only: it provides no confidentiality.

Usage

1. Choose encode or decode.
2. Paste text to encode, or a Base64URL value to decode.
3. Read the result; use Copy result to reuse it.

Examples

These are examples, not current values: they use fixed inputs, while the interactive tool computes live results in your browser.

Encode ASCII

{
  "mode": "encode",
  "value": "hello"
}

Encode Unicode

{
  "mode": "encode",
  "value": "café 🌍"
}

Decode a Base64URL value

{
  "mode": "decode",
  "value": "aGVsbG8"
}

Limitations

Where Base64URL is used

Base64URL carries binary data through text-only channels that forbid '+' and '/'. JSON Web Tokens, URL parameters and file names are the common cases. The standard Base64 tool remains the right choice when the surrounding system expects the '+'/'/' alphabet.