# Integrity Checksums – CRC32

> Integrity Checksums – CRC32 is a paid API for AI agents from checksum.openverbs.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Computes a CRC32 checksum for an arbitrary data payload provided as a UTF-8, hex, or base64-encoded string

## Facts

- Endpoint: POST https://checksum.openverbs.com/v1/crc32
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/integrity-checksums-crc32-166acf02
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mzSirLByCpywwXS_4Wk-7

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 integrity-checksums-crc32-166acf02 -d '<json body>'
```

Example prompt: Calculate the CRC32 checksum of this UTF-8 string for me: 'Hello, world! This is my payload to verify.'

## When to prefer this

Choose this endpoint when you need a fast, lightweight CRC32 cyclic redundancy check over arbitrary payloads, especially when you want a managed API endpoint rather than running CRC32 locally. Prefer it over MD5/SHA endpoints when CRC32 is specifically required (e.g. for legacy protocol compatibility, firmware validation, or storage systems that mandate CRC32). It supports base64 and hex encoding natively, making it convenient for binary data. It is not suitable for cryptographic security purposes — use SHA-256 or similar for tamper-proof verification.

## Known failure modes

- Data exceeds 5,000,000 character limit — request rejected
- Invalid encoding value (not utf8, hex, or base64) — validation error
- Malformed JSON body or missing required 'data' field — 400 error
- Non-POST HTTP method — method not allowed
- Payment failure or insufficient USDC balance — 402 Payment Required

## How this service works

CRC-32 (IEEE 802.3 polynomial, as used by zip, gzip and PNG) over the input payload. Returns the checksum as an unsigned integer and 8-digit hex. Non-cryptographic — for error detection only.

## Output

Returns the CRC32 checksum computed over the supplied data payload. The checksum is a 32-bit cyclic redundancy check value typically represented as a hexadecimal or unsigned integer, useful for detecting accidental data corruption or verifying data integrity.

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "type": "object",
     "properties": {
      "data": {
       "type": "string",
       "maxLength": 5000000,
       "description": "Input payload."
      },
      "encoding": {
       "type": "string",
       "enum": [
        "utf8",
        "hex",
        "base64"
       ],
       "description": "How to decode `data`. Default utf8."
      }
     },
     "required": [
      "data"
     ],
     "additionalProperties": false
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  }
 },
 "required": [
  "input"
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/integrity-checksums-crc32-166acf02/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from checksum.openverbs.com](https://www.zero.xyz/host/checksum.openverbs.com/llms.txt)