# Synapse API — Kaia Blockchain Transaction History

> Synapse API — Kaia Blockchain 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 2026-09-13).

Retrieves paginated transaction history for addresses on the Kaia blockchain network, with filtering by block range, category, and address.

## Facts

- Endpoint: POST https://synapse-api-brown.vercel.app/api/kaia/tx/history
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/synapse-api-kaia-blockchain-transaction-history-83deba0a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FpxkWEfOUY8T54JjBNvRN

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-kaia-blockchain-transaction-history-83deba0a -d '<json body>'
```

Example prompt: Pull the last 100 transactions sent from Kaia address 0xAbC123... to 0xDeF456... in descending order, including metadata and excluding zero-value transfers.

## When to prefer this

Choose this endpoint when you need structured, filterable transaction history specifically on the Kaia blockchain, with support for block-range filtering, address-level queries, category filtering, and pagination. Prefer this over generic block explorers when you need programmatic, pay-per-call access without rate-limit subscriptions.

## Known failure modes

- Invalid or malformed address returns error response
- Block range too large may be rejected or timeout
- Invalid pageKey causes pagination failure
- Unsupported category value results in empty or error response
- Network unavailability causes 5xx error
- Payment failure via x402 prevents access

## 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 transaction records on the Kaia blockchain matching the specified filters, including sender/receiver addresses, block numbers, transaction categories, and optionally rich metadata such as token names, values, and timestamps. A pageKey is returned when more results are available.

## 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-kaia-blockchain-transaction-history-83deba0a/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)