HTTP 402 for AI Agents
HTTP 402 is becoming the handshake between autonomous agents and paid APIs. The protocol can request payment; SatGate decides whether the agent has authority to spend, access, and continue — then preserves proof of the decision.
What HTTP 402 means in an agent world
For years, HTTP 402 Payment Required was mostly dormant. AI agents make it useful: a paid API can respond with a machine-readable challenge instead of forcing a human through checkout.
That challenge may point to different rails: card-based credentials, shared payment tokens, paid-rail context invoices, or future protocols. But the payment challenge is not the governance layer.
SatGate sits before upstream access and applies policy: identify the agent, confirm authority, estimate cost, enforce budgets, decide whether the rail is allowed, record the challenge, and unlock only scoped access after proof.
A 402-aware control plane asks
HTTP 402 flow types
Treat 402 as a protocol surface, not a single payment system. paid-rail context is one paid rail; x402, AgentCore Payments, Pay.sh, and payment-token flows are separate rails that still need governance.
Where SatGate fits in a 402 exchange
Agent requests
An agent calls a paid API, model endpoint, MCP tool, or dataset.
SatGate evaluates
Policy checks identity, scope, budget, route, tenant, and allowed payment rail.
402 is handled
SatGate can issue, observe, or audit a payment challenge depending on the route.
Access is governed
Only approved, scoped, metered, auditable access proceeds upstream.
L402 is a paid rail, not the governance layer
paid-rail context can carry payment proof: an API returns a 402 challenge, the agent or wallet client pays a Lightning invoice, and proof unlocks scoped access. SatGate evaluates the action before payment/access and records proof after the decision.
Other 402 rails still need policy
Stripe-style shared payment tokens, card credentials, and future payment protocols can help agents pay. They do not replace request-path controls for budget, scope, revocation, metering, receipts, or Evidence Pack proof.
FAQ
HTTP 402 for AI agents questions
What is HTTP 402 for AI agents?
HTTP 402 lets an API tell an AI agent that payment is required before access. The response can include a machine-readable challenge describing how to pay.
Is HTTP 402 the same as L402?
No. HTTP 402 is the status code. L402 is a Lightning-based payment and access pattern that uses HTTP 402. paid-rail context is one rail SatGate can govern in the request path.
How are Stripe shared payment tokens different from L402?
Stripe-style shared payment tokens are a payment-credential method for supported 402 flows. L402 uses Lightning payment proof to unlock scoped API access. They are separate rails.
Why do 402 payment challenges need policy?
A payment challenge tells the agent how to pay, but it does not decide whether the agent should be allowed to spend, which budget applies, whether the route is in scope, or how the event should feed the Evidence Pack.
Related guides
Policy-to-Proof
See how paid access decisions become Evidence Pack proof.
Govern AI agents
Govern paid agent actions before execution.
L402 agent payments
Understand paid-rail context as one paid rail for governed agent/API access.
Agent payment controls
Policy, budgets, approval, receipts, and payment rails for AI agents.
Economic firewall
Control agent access, spend, and paid-rail context before upstream API calls execute.
L402 API pricing calculator
Estimate request-native pricing for agent/API paid-access scenarios.
Govern paid agent access before execution
HTTP 402 can carry payment context. SatGate turns that context into governed action: authority, policy, budget, proof, and an Evidence Pack receipt for every paid request.