# Synapse API — Ethereum NFT Metadata Lookup

> Synapse API — Ethereum NFT Metadata Lookup is a paid API for AI agents from synapse-api-brown.vercel.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).

Fetches on-chain and off-chain metadata for a specific Ethereum NFT given its contract address and token ID

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/ethereum/nft/metadata
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-ethereum-nft-metadata-lookup-0297205f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_qyjUlpjUoYzNppp7-vQV4

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 synapse-api-ethereum-nft-metadata-lookup-0297205f -d '<json body>'
```

Example prompt: Can you pull the metadata for Ethereum NFT contract 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D token ID 1234 — I want to see its name, image, and traits.

## When to prefer this

Choose this endpoint when you need quick, pay-per-call NFT metadata resolution on Ethereum without a long-term API subscription. Ideal for agents that occasionally need to resolve NFT metadata on-demand rather than in bulk, and when you want to avoid rate limits or API key management overhead. Prefer over general-purpose blockchain explorers when you need structured, normalized metadata output rather than raw contract data.

## Known failure modes

- Invalid or non-checksummed contract address returns an error
- Token ID does not exist on the contract (returns 404 or empty metadata)
- NFT metadata hosted on a down or rate-limited IPFS/HTTP server may return incomplete data
- Contract address is not an NFT contract (ERC-721/ERC-1155) — may return null or error
- Payment failure via x402 protocol returns 402 before the request is processed

## How this service works

High-speed API suite for AI processing, web scraping, and smart data utilities across 57+ blockchain networks. Pay-per-call via x402.

## Output

Returns structured metadata for the specified Ethereum NFT including its name, description, image URL, external URL, animation URL (if any), and an array of trait attributes (trait_type and value pairs), along with token standard and collection-level details where available.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "tokenId": {
   "type": "string"
  },
  "contractAddress": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synapse-api-ethereum-nft-metadata-lookup-0297205f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from synapse-api-brown.vercel.app](https://www.zero.xyz/host/synapse-api-brown.vercel.app/llms.txt)