# Penny Engine: buy a real x402 API call

One step to see what Penny Engine can fulfill for your agent, without creating an account or paying for discovery.
Free machine task matching: POST https://penny-agent-api-production.up.railway.app/api/choose-service
Example: {"task":"check Base network gas price and block height","maxPriceUsd":0.001}

## Simplest machine checkout (GET, no request inputs)
GET https://penny-paid-batch-production.up.railway.app/api/base-network
Cost: $0.001 Base USDC, standard x402 payment challenge and retry.
With an already configured and funded buyer-owned AgentCash wallet:
npx agentcash@latest fetch https://penny-paid-batch-production.up.railway.app/api/base-network

## Test a machine wallet's x402 payment compatibility
npx agentcash@latest fetch https://penny-paid-batch-production.up.railway.app/ping

## Validate another agent's structured JSON
Free fixed-data example: https://penny-paid-batch-production.up.railway.app/demo/proof-gate
npx agentcash@latest fetch https://penny-paid-batch-production.up.railway.app/api/proof-gate -m POST -b '{"result":{"status":"completed"},"expectations":{"equals":{"status":"completed"}}}'

## Fulfill a three-step catalog processing task
Try this free fixed-data demo: https://penny-paid-batch-production.up.railway.app/demo/fulfill
Validate real CSV inputs for free: POST https://penny-paid-batch-production.up.railway.app/api/fulfill/preflight
Paid workflow: POST https://penny-paid-batch-production.up.railway.app/api/fulfill
Exact JSON input schema and examples: https://penny-paid-batch-production.up.railway.app/openapi.json

## Install once for free task selection (MCP)
Remote MCP: https://penny-agent-api-production.up.railway.app/mcp
Choose the free tool penny_choose_service and send a task description.
Call penny_fulfillment_preflight to validate a catalog request before authorizing payment.
HTTP machine-readable buyer guide: https://penny-agent-api-production.up.railway.app/agent-buying-guide.json

## Payment safety and limitations
These commands and links initiate an actual paid request if a configured buyer wallet automatically authorizes it. They are NOT free paid-service trials.
The buyer must control its own wallet, hold Base USDC, and enforce its spending policy. Never provide private keys or wallet credentials to Penny Engine.
An initial 402 challenge is not a completed payment. We have not independently verified an outside paid settlement for Penny Engine.
No outside purchases, bookings, code execution or generalized agent tasks are promised.