# UPC-E Luhn Check

> UPC-E Luhn Check is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-25).

Validates whether an 8-digit UPC-E barcode number passes the Luhn algorithm check digit verification.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-upc-e?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-25
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/upc-e-luhn-check-cab935ff
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Ob2KFgJxUbtKAF4nYlYs9

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 upc-e-luhn-check-cab935ff -d '<json body>'
```

Example prompt: Can you check whether the UPC-E barcode '01234565' passes the Luhn algorithm validity check?

## When to prefer this

Use this endpoint when you need to verify that an 8-digit UPC-E barcode passes the Luhn check digit algorithm. Prefer the free sandbox endpoint POST /v1/sandbox/check-upc-e during development and testing to avoid the $0.01 USDC charge. Use this paid endpoint for production validation workflows where reliability is required.

## Known failure modes

- Input string is not 8 digits — validation fails or returns error
- Non-numeric characters in input cause rejection
- Empty or missing value field returns error
- String exceeds maxLength or is less than 1 character

## How this service works

Call when an agent needs whether an 8-digit UPC-E-shaped number passes Luhn. Exact $0.01 USDC. Prefer unpaid POST /v1/sandbox/check-upc-e first.

## Output

Returns a boolean or structured result indicating whether the provided 8-digit UPC-E number passes the Luhn algorithm check digit validation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "description": "JSON value for schema-check SKUs. Omit it on string checks such as email or IBAN."
  },
  "value": {
   "type": "string",
   "examples": [
    "123"
   ],
   "maxLength": 20000,
   "minLength": 1,
   "description": "Value to check. The route description names the format: email, phone, IBAN, postal code, VAT, national id, or similar."
  },
  "schema": {
   "description": "JSON Schema document for schema-check SKUs. Omit it on string checks."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/upc-e-luhn-check-cab935ff/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)