# Synapse API — Sonic Transaction History

> Synapse API — Sonic 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 Sonic blockchain network, with filtering by block range, category, and address.

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/sonic/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-sonic-transaction-history-c7e89ceb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3e3xEjAvKGLOGvRXQbZsF

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-sonic-transaction-history-c7e89ceb -d '<json body>'
```

Example prompt: Pull the last 25 transactions sent from 0xAbC123... on the Sonic network, sorted newest first, and include metadata — skip any zero-value transfers.

## When to prefer this

Use this endpoint when you need to look up historical transaction activity specifically on the Sonic blockchain network, with flexible filtering by address, block range, asset category, and value. Prefer this over general Ethereum or EVM endpoints when the target chain is Sonic, and when you need pagination support for large result sets.

## Known failure modes

- Invalid address format returns 400 error
- Block range too large may return timeout or partial results
- Unknown category type causes validation error
- Invalid pageKey returns empty or error response
- Network unavailable on Sonic node returns 503
- maxCount exceeding allowed limit may be clamped or rejected

## 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 transactions matching the specified filters, including transaction hashes, block numbers, from/to addresses, asset values, and optionally rich metadata. Supports pagination via a pageKey for retrieving large result sets incrementally.

## 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-sonic-transaction-history-c7e89ceb/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)