The status is a signal
HTTP 402 indicates payment is required but does not by itself define asset, network or proof format.
Agent Commerce & Security · PDF FIELD GUIDE · 2026
HTTP 402 Payment Required Explained
Status semantics, payment challenges and implementation boundaries
SML-X402-0024-PAGE PDF$29 ONE TIMEINSTANT DELIVERY
THE OUTCOME
Understand the role of HTTP 402 and the additional protocol decisions required for usable machine payments.
Primary search intent: HTTP 402 Payment Required
CORE MODEL
Four ideas before action.
Terms must be machine-readable
Price, recipient, expiry, resource and payment method need unambiguous representation.
Retry must be bound
Payment proof should attach to the intended request and resist replay or substitution.
Delivery is separate
A valid transfer does not prove that the requested resource was correct or accepted.
ACTION CHECKLIST
A six-step review process.
- Specify price and denomination
- Bind terms to resource and expiry
- Validate network and recipient
- Protect proof against replay
- Return deterministic errors
- Record payment and delivery evidence
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
Protocol support and settlement finality vary by implementation and network.
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. Protocol support and settlement finality vary by implementation and network.