Define the billable unit
A request, record, token, second or successful response creates different incentives.
Agent Commerce & Security · PDF FIELD GUIDE · 2026
Pay-Per-Call API Guide
Pricing units, metering, receipts and customer-safe failure handling
SML-X402-0034-PAGE PDF$29 ONE TIMEINSTANT DELIVERY
THE OUTCOME
Design an API purchase flow where price, unit, fulfillment and refund rules are clear before payment.
Primary search intent: pay per call API
CORE MODEL
Four ideas before action.
Quote before execution
Return enough terms for the buyer to evaluate price, scope and expiry.
Make retries idempotent
Network failures should not silently create duplicate charges or deliveries.
Issue useful receipts
Correlate quote, payment, request, response and acceptance status.
ACTION CHECKLIST
A six-step review process.
- Name the unit and included limits
- Publish deterministic pricing
- Use idempotency keys
- Separate payment from acceptance
- Document timeout and refund rules
- Expose usage and receipt records
PRIMARY SOURCES
Verify the moving parts.
The PDF includes a source map and explicit research boundary. Product and regulatory details can change; current official material controls.
x402 protocol documentation →x402 specification repository →Model Context Protocol specification →OWASP API Security Top 10 →TRUTH BOUNDARY
This guide does not determine legal, tax, sanctions or money-transmission obligations.
AI tools assisted drafting and layout. SCRIPTMASTERLABS is responsible for editorial structure and source selection. No personalized investment, legal, tax, medical, regulatory, advertising or cybersecurity advice.
FAQ
Before you buy.
What format is this product?
A four-page PDF field guide delivered immediately after successful Stripe Checkout.
Is this a subscription?
No. It is a one-time purchase.
Does this guarantee a result?
No. This guide does not determine legal, tax, sanctions or money-transmission obligations.