# CRC16 Hex Checksum Calculator

> CRC16 Hex Checksum Calculator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Computes the CRC16 checksum of a given text string and returns the result as a hexadecimal value.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/checksum-crc16-hex?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/crc16-hex-checksum-calculator-9e27356f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_M1LUg4J9CLuLGxsT5sLnb

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability crc16-hex-checksum-calculator-9e27356f -d '<json body>'
```

Example prompt: Can you compute the CRC16 checksum of the text 'Hello, World!' and give me the result as a hex string?

## When to prefer this

Choose this endpoint when you need a fast, deterministic CRC16 hex checksum without implementing the algorithm locally. It is especially useful in agent workflows where you cannot or do not want to execute arbitrary code, and when you need a lightweight integrity fingerprint rather than a cryptographic hash. If cost is a concern, try the free sandbox POST /v1/sandbox/checksum-crc16-hex first.

## Known failure modes

- Empty or missing 'text' field returns a validation error
- Text exceeding 100,000 characters is rejected
- Missing or invalid API key returns 401/402 unauthorized
- Malformed JSON body returns 400 bad request

## How this service works

Call when an agent needs a crc16 checksum of text as hex. No network and no LLM. Exact $0.001 USDC. Prefer unpaid POST /v1/sandbox/checksum-crc16-hex first.

## Output

Returns a hexadecimal string representing the CRC16 checksum of the submitted text, computed server-side without any LLM or network dependencies. The response is deterministic: identical inputs always produce the same hex output.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "key": {
   "type": "string",
   "maxLength": 512,
   "minLength": 1,
   "description": "HMAC secret. Required on HMAC SKUs. Omit it for plain digests and checksums. The key is not stored."
  },
  "text": {
   "type": "string",
   "examples": [
    "hello"
   ],
   "maxLength": 100000,
   "minLength": 1,
   "description": "Message to digest. For raw-hex SKUs this is hex bytes; for utf16 or latin1 SKUs it is decoded with that encoding. Otherwise it is UTF-8 text."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/crc16-hex-checksum-calculator-9e27356f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)