# Synapse API — Monad Transaction History

> Synapse API — Monad 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 Monad blockchain network, with filtering by block range, category, and metadata options.

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/monad/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-monad-transaction-history-ae80e4c7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EbPxul9werxlbYmCSfdEz

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-monad-transaction-history-ae80e4c7 -d '<json body>'
```

Example prompt: Show me the last 25 transactions sent from Monad address 0xABC...123 to 0xDEF...456, descending order, with metadata included and zero-value transfers excluded.

## When to prefer this

Choose this endpoint when you need on-chain transaction history specifically for the Monad blockchain network, with flexible filtering by address, block range, category, and sort order. Prefer it over generic blockchain explorers when you need programmatic, paginated access via a pay-per-call model without API key setup.

## Known failure modes

- Invalid address format returns an error response
- Invalid block range (fromBlock > toBlock) may return empty results or error
- Unrecognized category values may be silently ignored or return an error
- pageKey mismatch or expiry leads to pagination errors
- Rate limiting or payment failures (x402) result in 402 Payment Required
- Empty result set if no transactions match the given filters

## 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 the Monad blockchain matching the specified filters, including transaction details such as from/to addresses, block numbers, transfer categories, and optionally 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-monad-transaction-history-ae80e4c7/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)