# Synapse API — X Layer Transaction History

> Synapse API — X Layer 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 X Layer (OKX) blockchain network

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/xlayer/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-x-layer-transaction-history-5457dbe7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CPLV6MzrEL7C0aACS3lhr

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-x-layer-transaction-history-5457dbe7 -d '<json body>'
```

Example prompt: Pull the last 25 transactions for wallet 0xAbC123...on X Layer, sorted newest first, including metadata and excluding zero-value transfers.

## When to prefer this

Use this endpoint when you need historical transaction data specifically for the X Layer (OKX Chain) blockchain. It supports flexible filtering by address direction, block range, transaction category, and ordering, making it suitable for wallet audits, portfolio analytics, and on-chain activity monitoring on X Layer. Prefer this over generic blockchain explorers when you need programmatic, paginated access with metadata enrichment.

## Known failure modes

- Invalid address format returns validation error
- Unknown or malformed pageKey causes pagination failure
- fromBlock greater than toBlock returns empty result or error
- maxCount exceeding API limits may return partial results or error
- Unsupported category values may be silently ignored or cause error
- Network downtime on X Layer data provider causes 5xx response
- Missing required fields may return 400 bad request

## 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 X Layer network matching the specified filters, including transfer details such as from/to addresses, block numbers, transaction hashes, asset categories, and optionally enriched metadata. A pageKey is provided 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-x-layer-transaction-history-5457dbe7/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)