Hex bytes concat

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

Concatenate a bounded ordered list of lowercase hex byte strings into one hex string.

Use when you need to: hex bytes concat · concatenate hex byte strings · join hex byte parts.

Supported

• hex bytes concat
• concatenate hex byte strings
• join hex byte parts

Not supported

• uppercase hex
• 0x prefix
• byte separators
• insert delimiter between parts
• flatten nested arrays
• decode hex to text

Behavior

• parts is an ordered array of lowercase hex byte strings: 0-9 and a-f only, two hex digits per byte, no 0x prefix, no separators, no whitespace, no uppercase.
• parts has at most 1000 items.
• Each part and the concatenated result are bounded to 128000 bytes (256000 hex characters); exceeding either limit is rejected before the result is built.
• Result hex is every part decoded to bytes and concatenated in array order, then re-encoded as lowercase hex. No delimiter is inserted between parts.
• An empty parts array, and an array containing only empty strings, both produce an empty result.

Input

• parts (array of string, required): max items 1000; each max length 256000

Output

• hex (string, required): max length 256000

Limits

• max parts: 1000
• max input bytes per part: 128000
• max output bytes: 128000

Example

Request input:

{
  "parts": [
    "ab",
    "cd",
    "ef"
  ]
}

Response:

{
  "result": {
    "hex": "abcdef"
  }
}

How to call it

MCP

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

{
  "id": "hex-bytes-concat",
  "version": "1.0.0",
  "input": {
    "parts": [
      "ab",
      "cd",
      "ef"
    ]
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/hex-bytes-concat/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"parts":["ab","cd","ef"]}'

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

CLI

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

Get the client at /clients/cli/.

Related tools

• Hex bytes xor: Byte-wise XOR of two equal-length lowercase hex byte strings. Transformation only; no cryptographic security claim.
• Hex bytes slice: Slice a lowercase hex byte string by explicit byte-index bounds, half-open like Array.slice.
• UTF-8 hex: Encode a Unicode string as lowercase hex of its UTF-8 bytes. Transformation only; no security claim.
• Adler-32: Adler-32 of UTF-8 bytes (RFC 1950). Integrity check only; no security claim.
• Base64 UTF-8: Decode standard Base64 to UTF-8 text. Transformation only; no security claim.
• CRC-32: CRC-32 of UTF-8 bytes (ISO 3309 / ZIP / PNG polynomial). Integrity check only; no security claim.