# Synapse API — Arbitrum NFT Metadata Lookup

> Synapse API — Arbitrum 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 2026-10-18).

Fetches on-chain NFT metadata for a given contract address and token ID on the Arbitrum network

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/arbitrum/nft/metadata?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-arbitrum-nft-metadata-lookup-d17accb5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Nen2JI4K_ixfG0oYz8CdV

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-arbitrum-nft-metadata-lookup-d17accb5 -d '<json body>'
```

Example prompt: Can you pull the metadata for token ID 1234 from the Arbitrum NFT contract at 0xAbCd1234...5678? I want to see its name, image, and traits.

## When to prefer this

Choose this endpoint when you specifically need NFT metadata from the Arbitrum Layer-2 network and want a pay-per-call model without a subscription. Prefer this over general blockchain explorers when you need structured metadata output suitable for agent pipelines, or when your use case spans multiple NFT contracts programmatically on Arbitrum.

## Known failure modes

- Invalid or non-existent contract address returns an error or empty response
- Token ID not minted or out of range returns a not-found error
- Contract does not implement standard ERC-721/ERC-1155 metadata may return incomplete data
- Network congestion or RPC issues may cause timeout
- Payment failure via x402 protocol blocks the call

## 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 on-chain NFT metadata for the specified token, typically including the token name, description, image URL, and an array of trait attributes as defined by the NFT contract on Arbitrum.

## 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-arbitrum-nft-metadata-lookup-d17accb5/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)