# Palindrome Number Checker

> Palindrome Number Checker is a paid API for AI agents from sovereign-x402-zeta.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-11).

Checks whether a given number is a palindrome (reads the same forwards and backwards).

## Facts

- Endpoint: POST https://sovereign-x402-zeta.vercel.app/api/v1/sequence/palindrome?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/palindrome-number-checker-ace869c0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2PP05CTnro3cQnyA-jkZe

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 palindrome-number-checker-ace869c0 -d '<json body>'
```

Example prompt: Can you check if 12321 is a palindrome number?

## When to prefer this

Use this endpoint when you need a quick, paid microservice check for palindrome property on a number, especially in an agentic workflow that already uses x402 micropayment infrastructure. Prefer it over rolling your own logic when you want a verified, external computation step in your pipeline.

## Known failure modes

- Missing or malformed 'body' in the request returns a validation error
- Non-numeric input may return an error or unexpected result
- Negative numbers may not be considered palindromes depending on implementation
- Payment failure or insufficient USDC balance blocks the request

## How this service works

Check if a given number is a palindrome.

## Output

Returns a result indicating whether the submitted number is a palindrome (reads identically forwards and backwards), typically as a boolean or equivalent true/false response.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "properties": {},
     "additionalProperties": true
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/palindrome-number-checker-ace869c0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from sovereign-x402-zeta.vercel.app](https://www.zero.xyz/host/sovereign-x402-zeta.vercel.app/llms.txt)