# Clink Forge State Population Lookup

> Clink Forge State Population Lookup is a paid API for AI agents from api.clinkforge.com, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-16).

Returns government-sourced population data for a US state by state ID, with cryptographic provenance and attestation, paid per call via x402/USDC.

## Facts

- Endpoint: GET https://api.clinkforge.com/v1/p/state-population-lookup
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/clink-forge-state-population-lookup-16ad086a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kVcu58DUozJYDAYNI0OmT

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 clink-forge-state-population-lookup-16ad086a
```

Example prompt: Pull the official government-sourced population figure for California (state ID 'CA') from Clink Forge — I need the cryptographically signed, provenance-chained result so I can verify the source.

## When to prefer this

Choose this endpoint when you need official, government-sourced US state population data with cryptographic provenance and an on-chain payment trail — particularly when auditability, citation of authority, or machine-verifiable data integrity matters. It requires no API key or account, making it ideal for autonomous agents that can pay per call in USDC. Prefer it over unattested data APIs when compliance, reproducibility, or verifiable sourcing is a requirement.

## Known failure modes

- Invalid or missing 'id' query parameter (too long, wrong format) returns a validation error
- Payment failure over x402 if insufficient USDC balance — call is rejected before data is returned
- Unknown state ID returns empty data set or not-found error
- Network or blockchain settlement timeout causing delayed or failed response
- Signing service unavailability causing attestation failure

## How this service works

Pay per call over x402. USDC on Base, no account, no API key. 28 government-sourced data products at $0.001–$0.05 per call, every response signed and provenance-chained.

## Output

Returns a JSON object containing one or more population data rows for the requested state, a provenance chain (hash, authority name, source government URL, and observation timestamp), a cryptographic attestation (signature, result digest, signing key ID), a payment receipt (amount in USD and on-chain settlement reference), product metadata (name, version), and a row count.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "const": "http"
    },
    "method": {
     "const": "GET"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "id"
     ],
     "properties": {
      "id": {
       "type": "string",
       "maxLength": 4
      }
     },
     "additionalProperties": false
    }
   }
  },
  "output": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "data": [
   {
    "field": "value",
    "_record_id": "R-100"
   }
  ],
  "product": "example-product",
  "row_count": 1,
  "provenance": [
   {
    "hash": "sha256...",
    "authority": "AGENCY",
    "source_url": "https://agency.gov/data",
    "observed_at": "2026-08-25T00:00:00Z"
   }
  ],
  "attestation": {
   "signature": "base64...",
   "result_digest": "sha256...",
   "signing_key_id": "forge-signing-1"
  },
  "payment_receipt": {
   "amount_usd": 0.01,
   "settlement_ref": "0xtx..."
  },
  "product_version": 1
 },
 "description": "data rows + provenance chain + attestation"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/clink-forge-state-population-lookup-16ad086a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.clinkforge.com](https://www.zero.xyz/host/api.clinkforge.com/llms.txt)