# Synapse API — Arbitrum NFT Sales

> Synapse API — Arbitrum NFT Sales 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).

Retrieves NFT sales events on the Arbitrum blockchain, filterable by block range and contract address.

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/arbitrum/nft/sales?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-arbitrum-nft-sales-d546095c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_w9y8LTh5Qg9WU0Ks_AEUO

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-sales-d546095c -d '<json body>'
```

Example prompt: Pull the last 50 NFT sales on Arbitrum for contract 0xAbCd1234... sorted in descending order from block 180000000 down to block 179000000.

## When to prefer this

Choose this endpoint when you need on-chain NFT sales data specifically from the Arbitrum network, with the ability to filter by block range and contract address. Prefer it over generic blockchain explorers when you need structured, pay-per-call access without managing your own node infrastructure. Best suited for agents doing real-time or historical NFT market analysis on Arbitrum.

## Known failure modes

- Invalid contract address format returns an error or empty result
- fromBlock greater than toBlock yields no results or an error
- Block range too large may time out or return partial results
- Unrecognized or non-NFT contract address returns empty results
- Missing required fields may cause a 400 bad request
- Payment not attached or insufficient USDC balance returns 402

## 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 a list of NFT sale events on the Arbitrum network, each including details such as the token ID, sale price, buyer/seller addresses, and block number, filtered according to the specified contract address and block range parameters.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "limit": {
   "type": "number"
  },
  "order": {
   "enum": [
    "asc",
    "desc"
   ],
   "type": "string"
  },
  "toBlock": {
   "type": "number"
  },
  "fromBlock": {
   "type": "number"
  },
  "contractAddress": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synapse-api-arbitrum-nft-sales-d546095c/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)