# Synapse API — Optimism Transaction History

> Synapse API — Optimism 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 Optimism blockchain network

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/optimism/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-optimism-transaction-history-7dbba2d9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ADm_F4bs8iR6ynFn3MIvF

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-optimism-transaction-history-7dbba2d9 -d '<json body>'
```

Example prompt: Can you pull the last 25 transactions for the Optimism wallet 0xAbC123...def456, sorted newest first, and include metadata?

## When to prefer this

Use this endpoint when you need historical transaction data specifically for the Optimism (OP Mainnet) blockchain. Prefer this over generic blockchain explorers when you need programmatic, paginated, and filterable access to address-level transaction history with metadata, and when you are already working within the Synapse API ecosystem for multi-chain queries.

## Known failure modes

- Invalid or missing address formats return a validation error
- Non-existent block range returns empty results or an error
- Invalid category enum values cause a 400 bad request
- Expired or invalid pageKey may return an error or restart pagination
- Rate limiting or payment failure returns a 402 Payment Required

## 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 paginated list of asset transfer transactions on the Optimism network matching the specified filters, including transaction hashes, block numbers, from/to addresses, asset categories, values, and optionally full transaction metadata. Also returns a pageKey for fetching subsequent pages.

## 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-optimism-transaction-history-7dbba2d9/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)