# Synapse API — zkSync NFT Metadata Lookup

> Synapse API — zkSync 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 NFT metadata (name, image, attributes, etc.) for a given token ID and contract address on the zkSync blockchain network.

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/zksync/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-zksync-nft-metadata-lookup-f1fa0aa3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_j8XmgjsIaM3-NMrmr1FrU

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-zksync-nft-metadata-lookup-f1fa0aa3 -d '<json body>'
```

Example prompt: Can you pull up the metadata for token ID 1337 from the NFT contract 0xAbCd1234... on zkSync — I want to see its name, image, and any traits it has.

## When to prefer this

Use this endpoint when you specifically need NFT metadata from the zkSync or zkSync Era Layer-2 network. It is preferable over generic multi-chain NFT APIs when you know the asset lives on zkSync and want fast, pay-per-call access without a subscription. It's ideal for agents that need lightweight, on-demand token metadata lookups without maintaining their own blockchain node.

## Known failure modes

- Invalid or non-existent contract address returns an error or empty response
- Token ID not minted or out of range returns not-found error
- Contract is not an NFT contract (e.g., ERC-20) returns metadata parsing failure
- zkSync network congestion or RPC unavailability causes timeout
- Malformed input (wrong type for tokenId or contractAddress) causes validation error
- Metadata hosted off-chain (IPFS/HTTP) may be unavailable if the gateway is down

## 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 for the specified zkSync token, typically including token name, description, image URL, animation URL (if any), and a list of attributes/traits such as background, rarity tier, and other collection-specific properties.

## 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-zksync-nft-metadata-lookup-f1fa0aa3/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)