# Polymer Labs Proof Generation & Query API

> Polymer Labs Proof Generation & Query API is a paid API for AI agents from api.polymer.zone, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-14).

Generates and queries cross-chain event proofs using JSON-RPC, enabling verification of on-chain events across blockchain networks

## Facts

- Endpoint: POST https://api.polymer.zone/x402/v1
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/polymer-labs-proof-generation-query-api-d3de8a77
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_lzS9Tyyehi1W5dFh3f5sw

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 polymer-labs-proof-generation-query-api-d3de8a77 -d '<json body>'
```

Example prompt: Generate a cross-chain proof for an event on source chain 10 at block 21500000 with global log index 42, then query the job status once it's submitted.

## When to prefer this

Use this endpoint when you need cryptographic proofs of on-chain events across blockchain networks, particularly for cross-chain interoperability via IBC-style proofs. Prefer this over generic blockchain RPC endpoints when you specifically need Polymer Labs' proof generation infrastructure for verifying events from one chain on another.

## Known failure modes

- Invalid or missing srcChainId returns an error indicating unsupported chain
- Block number not yet finalized causes proof generation failure
- Invalid jobId in proof_query returns not-found error
- Malformed JSON-RPC request (missing jsonrpc version or id) returns parse error
- Payment not received (402) blocks request processing
- Log index does not exist at specified block returns empty or error response

## How this service works

Access Polymer Labs proof generation and query service

## Output

Returns a JSON-RPC response containing either a job ID for a newly submitted proof generation request (proof_request), or the current status and proof data for an existing job (proof_query), including the cryptographic proof needed to verify a cross-chain event.

## Example request

```json
{
 "id": 1,
 "method": "proof_request",
 "params": [
  {
   "srcChainId": 10,
   "globalLogIndex": 42,
   "srcBlockNumber": 21500000
  }
 ],
 "jsonrpc": "2.0"
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "id",
  "method",
  "params",
  "jsonrpc"
 ],
 "properties": {
  "id": {
   "type": "number",
   "description": "Request identifier"
  },
  "method": {
   "enum": [
    "proof_request",
    "proof_query"
   ],
   "type": "string",
   "description": "RPC method to invoke"
  },
  "params": {
   "type": "array",
   "description": "proof_request: [{srcChainId, srcBlockNumber, globalLogIndex}], proof_query: [jobId]"
  },
  "jsonrpc": {
   "enum": [
    "2.0"
   ],
   "type": "string",
   "description": "JSON-RPC protocol version"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/polymer-labs-proof-generation-query-api-d3de8a77/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.polymer.zone](https://www.zero.xyz/host/api.polymer.zone/llms.txt)