# Synapse API — Base NFT Metadata Lookup

> Synapse API — Base 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 2026-10-12).

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

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/base/nft/metadata?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-base-nft-metadata-lookup-fb3a4066
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mJyjjn2jCxM7wQpLLRmxi

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-base-nft-metadata-lookup-fb3a4066 -d '<json body>'
```

Example prompt: Can you pull the metadata for token ID 1234 on the Base NFT contract at 0x5180db8F5c931aaE63c74266b211F580155ecac8? I want to see its name, image, and traits.

## When to prefer this

Use this endpoint when you need to retrieve NFT metadata specifically on the Base blockchain by contract address and token ID. Prefer it over generic blockchain explorers when you need structured, agent-consumable metadata output with low latency. Best when building NFT display UIs, portfolio enrichment tools, or rarity analyzers targeting Base chain assets.

## Known failure modes

- Invalid contract address format returns an error or empty response
- Token ID does not exist on the contract, resulting in a not-found or revert error
- Contract is not a valid ERC-721 or ERC-1155 NFT contract
- Metadata stored on IPFS or external URI is unreachable or timed out
- Base network RPC node downtime causes lookup failures
- Malformed JSON in the token's metadata URI returns a parse 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 NFT metadata for the specified token on the Base blockchain, typically including the token name, description, image URL, external URL, and an attributes/traits array with trait types and values as defined in the token's on-chain or IPFS-linked metadata.

## 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-base-nft-metadata-lookup-fb3a4066/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)