# Synapse API — Unichain Transaction History

> Synapse API — Unichain 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 Unichain blockchain network

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/unichain/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-unichain-transaction-history-08b1613d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aB7h99VBzzXL1Rwgk0dFt

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-unichain-transaction-history-08b1613d -d '<json body>'
```

Example prompt: Pull the last 100 transactions sent from 0xABC...123 on Unichain, sorted newest first, and include full metadata for each one.

## When to prefer this

Use this endpoint when you need historical transaction data specifically on the Unichain network and want flexible filtering by address direction, block range, asset category, and ordering. Prefer this over generic blockchain explorers when you need programmatic, paginated access with metadata in a pay-per-call model without API key setup.

## Known failure modes

- Invalid address format returns a validation error
- Unsupported category type causes a 400 bad request
- fromBlock greater than toBlock returns empty results or an error
- Invalid pageKey causes pagination failure
- Rate limiting or payment failure via x402 returns 402 Payment Required
- Network or RPC downtime returns 503 or timeout

## 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 transactions on Unichain matching the specified filters, including fields such as transaction hash, block number, asset category, from/to addresses, value transferred, and optional metadata. A pageKey may be returned 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-unichain-transaction-history-08b1613d/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)