UTF-8 hex

utf8-hex · version 1.0.0 · Encoding & checksums · free, no key needed

Encode a Unicode string as lowercase hex of its UTF-8 bytes. Transformation only; no security claim.

Use when you need to: utf8 hex · hex encode utf8 · utf8 to hex.

Supported

• utf8 hex
• hex encode utf8
• utf8 to hex

Not supported

• decode hex
• uppercase hex
• 0x prefix
• encryption

Behavior

• UTF-8 encode text, then lowercase hex with two digits per byte and no separators or prefix.
• Empty text -> empty hex.
• This is a byte transform, not confidentiality or authenticity.

Input

• text (string, required): max length 256000

Output

• hex (string, required)

Limits

• max input bytes: 256000

Example

Request input:

{
  "text": "A"
}

Response:

{
  "result": {
    "hex": "41"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "utf8-hex",
  "version": "1.0.0",
  "input": {
    "text": "A"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/utf8-hex/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"text":"A"}'

The machine-readable contract is at /v1/tools/utf8-hex/versions/1.0.0.

CLI

node cli.mjs run utf8-hex 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• UTF-8 Base64: Encode a Unicode string as standard Base64 of its UTF-8 bytes. Transformation only; no security claim.
• Base64 UTF-8: Decode standard Base64 to UTF-8 text. Transformation only; no security claim.
• Hex bytes concat: Concatenate a bounded ordered list of lowercase hex byte strings into one hex string.
• Hex bytes slice: Slice a lowercase hex byte string by explicit byte-index bounds, half-open like Array.slice.
• Hex bytes xor: Byte-wise XOR of two equal-length lowercase hex byte strings. Transformation only; no cryptographic security claim.
• Adler-32: Adler-32 of UTF-8 bytes (RFC 1950). Integrity check only; no security claim.