# Synapse API — Arbitrum Transaction History

> Synapse API — Arbitrum Transaction History 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 2026-09-15).

Retrieves paginated transaction history for addresses on the Arbitrum blockchain network

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/arbitrum/tx/history
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-arbitrum-transaction-history-4be602f3
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_PHB15q3ygrQJZREBB9WCI

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-transaction-history-4be602f3 -d '<json body>'
```

Example prompt: Pull the last 25 transactions for Arbitrum address 0xABC123... in descending order, including metadata, and skip any zero-value transfers.

## When to prefer this

Use this endpoint when you need on-chain transaction history specifically for the Arbitrum (Layer-2) network with flexible filtering by address, block range, category, and ordering. Prefer this over Ethereum mainnet endpoints when the user's assets or activity are on Arbitrum. Useful for portfolio tracking, auditing, DeFi analytics, or any agent task requiring paginated Arbitrum transaction data at $0.01 per call.

## Known failure modes

- Invalid address format returns an error response
- fromBlock or toBlock out of valid range causes an error
- maxCount exceeding API limits may return partial results or error
- Invalid category values return a validation error
- pageKey mismatch or expiry may cause pagination errors
- Payment failure (x402) if insufficient USDC balance

## 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 transaction records on the Arbitrum network matching the specified filters, including transaction hashes, block numbers, sender/receiver addresses, asset amounts, token metadata (if withMetadata is true), and a pageKey for pagination through large result sets.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "order": {
   "enum": [
    "asc",
    "desc"
   ],
   "type": "string"
  },
  "pageKey": {
   "type": "string"
  },
  "toBlock": {
   "type": "string"
  },
  "category": {
   "type": "array",
   "items": {
    "type": "string"
   }
  },
  "maxCount": {
   "type": "number"
  },
  "fromBlock": {
   "type": "string"
  },
  "toAddress": {
   "type": "string"
  },
  "fromAddress": {
   "type": "string"
  },
  "withMetadata": {
   "type": "boolean"
  },
  "excludeZeroValue": {
   "type": "boolean"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/synapse-api-arbitrum-transaction-history-4be602f3/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)