Use this encoder when a receiving system, file format, protocol, puzzle, or historical cipher explicitly requires the named representation and its alphabet or key convention is known.

Unsigned decimal integer

Required string input.

Encode an exact decimal integer from 0 through 2^64−1 as unsigned LEB128 bytes, shown as uppercase hexadecimal. Signed zigzag encoding is a separate tool. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Varint bytes (hex)

The resulting varint bytes (hex) returned as a string.

• Encoding changes representation, not trustworthiness or meaning. Alphabet variants, padding, line wrapping, character encoding, byte order, unsupported characters, and malformed Unicode can affect interoperability; classical ciphers and checksums do not provide modern confidentiality or authenticity.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Round-trip representative values through the matching decoder and verify published test vectors where available. Use authenticated encryption for security and a cryptographic hash or MAC when integrity against an adversary is required.

• Zigzag Integer Encoder

  Encode integers with the zigzag mapping: n≥0 → 2n, n<0 → −2n−1.

• Base122 Encoder

  Encode UTF-8 text as Base122 artifact text, avoiding null, newline, carriage return, quote, ampersand, and backslash bytes.

• Base91 Encoder

  Encode UTF-8 text as basE91, a compact printable encoding for binary data.