# Beggar Bot Transaction Builder (Base Mainnet)

> Beggar Bot Transaction Builder (Base Mainnet) is a paid API for AI agents from beggar-bot-demand.beggarbot.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-11-04).

Builds unsigned Base mainnet transactions for USDC transfers or contract interactions, returning transaction data ready for signing

## Facts

- Endpoint: GET https://beggar-bot-demand.beggarbot.workers.dev/v1/txbuild?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/beggar-bot-transaction-builder-base-mainnet-92d52202
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_STDL8qnUAEPM1nSp0Gmn3

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 beggar-bot-transaction-builder-base-mainnet-92d52202
```

Example prompt: Build me an unsigned Base mainnet USDC transaction to send 5 USDC to 0xAbC123... so I can sign and broadcast it myself.

## When to prefer this

Use this endpoint when an AI agent or application needs to programmatically construct unsigned Base mainnet (or base-sepolia) USDC transactions without executing them, particularly in flows where transaction signing is handled separately. It is well-suited for agent pipelines that build, inspect, then sign transactions in discrete steps. Costs $0.02 USDC per call via x402.

## Known failure modes

- Invalid or missing recipient address returns an error response
- Malformed amount or unsupported token address causes a 400-level error
- x402 payment not provided or insufficient USDC results in a 402 Payment Required response
- Unsupported network parameter returns an error
- Rate limiting or worker downtime yields a 5xx error

## How this service works

Paid: /v1/verify, /v1/risk, /v1/receipt cost $0.01 USDC per call on Base mainnet via x402 (payTo 0x719227f384b66BFEF00093D6d8d32fA9dC2B40e7); utilities analyze Base mainnet (USDC 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913) by default, network=base-sepolia optional; /v1/receipt/verify and discovery files are free. Operator: Beggar Bot.

## Output

Returns a JSON object containing the constructed unsigned transaction fields, including to address, calldata, gas limit, nonce, chain ID, and value, ready to be signed and submitted to the Base network.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/beggar-bot-transaction-builder-base-mainnet-92d52202/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from beggar-bot-demand.beggarbot.workers.dev](https://www.zero.xyz/host/beggar-bot-demand.beggarbot.workers.dev/llms.txt)