# Synapse API — NFT Metadata Lookup

> Synapse API — 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 2026-10-16).

Fetches on-chain NFT metadata for a given contract address and token ID across 57+ blockchain networks

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/bob/nft/metadata?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-nft-metadata-lookup-fdb825b4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_o8v9WwTVAE_R1l4EtaOAM

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-nft-metadata-lookup-fdb825b4 -d '<json body>'
```

Example prompt: Can you look up the metadata for NFT token ID 42 on contract address 0xBC4CA0EdA7647A8aB7C2061c2E118A18a936f13D — I want to see its name, image, and traits.

## When to prefer this

Choose this endpoint when you need to programmatically retrieve NFT token metadata (name, image, attributes) given a specific contract address and token ID, especially across a broad range of EVM-compatible and non-EVM blockchains. Prefer it over general blockchain explorers when you want structured JSON metadata optimized for agent consumption, and when pay-per-call pricing ($0.01 USDC) via x402 is suitable for your use case.

## Known failure modes

- Invalid or non-existent contract address returns an error or empty response
- Token ID does not exist on the given contract — returns not found or null metadata
- Contract address is not an NFT contract (e.g. ERC-20) — returns schema mismatch error
- Network/chain not supported among the 57+ supported networks — returns unsupported chain error
- Metadata URI is off-chain and unreachable (IPFS gateway timeout, dead URL) — returns fetch failure
- Malformed input (missing contractAddress or tokenId) — returns validation error

## 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 NFT metadata including token name, description, image URL, external URL, animation URL, and an array of trait attributes (trait_type and value pairs) as stored on-chain or on the token's metadata URI for the specified contract and token ID.

## 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-nft-metadata-lookup-fdb825b4/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)