L402 Payment Rules, Enforced Before Access
Payment details can carry HTTP 402 payment proof. SatGate gives delegated clients bounded economic authority: it decides whether a human or platform delegated enough authority, unlocks only scoped access, and preserves proof for every paid action.
The next API call may require delegated paid access
AI agents increasingly call and combine APIs on behalf of people and companies. That creates a delegation problem: software may consume valuable APIs, but humans and platforms still need to define what is allowed and prove why.
Traditional API monetization assumes a human signs up, enters a card, picks a plan, stores a key, and then integrates. Delegated agent/API access needs a request-native flow: request resource, receive price, present proof, unlock scoped access, continue task.
L402 gives that flow an internet-native shape. SatGate treats it as payment details, governed by policy and proof before the request goes through.
Good fits for L402 payment rules
- Premium search, research, or enrichment endpoints.
- Datasets agents query occasionally but value highly.
- AI tools sold per use instead of by seat.
- MCP tools exposed to external agent ecosystems.
- APIs where authorization and payment should happen together.
How L402 payment rules work with SatGate
SatGate checks each request before it goes through. The API stays protected while the delegated client receives a machine-readable price and payment challenge.
Agent requests a resource
An autonomous agent calls a protected API, model, dataset, tool, or premium endpoint.
SatGate returns a 402 challenge
Instead of a subscription flow or sales gate, SatGate issues an L402 payment challenge tied to the request.
Payment proof is presented
A wallet, platform, or delegated payment building block satisfies the invoice through SaturnZap or another L402-capable client.
Proof unlocks access
SatGate verifies payment and releases a scoped credential or forwards the approved request.
Usage is attributed
Every paid request is tied to delegated permissions, agent identity, route, price, policy, and settlement evidence.
Proof becomes request-native
Each paid request can carry identity, policy, price, payment proof, and access decision.
402 is a surface, not one rail
L402, shared payment tokens, and payment credentials are different layers
HTTP 402 can carry different payment challenges. Some flows use card credentials or shared payment tokens. L402 is one payment method for request-native API access. Other payment methods (x402, AgentCore Payments, and Pay.sh) also use HTTP 402 as their surface but settle differently.
The important control-plane question is broader than payment: whether the request has delegated permissions, plus budget, scope, and policy approval, before paid access is unlocked.
Explore the payment-control stack
Governed L402 payment requirements
Machine-readable price
Delegated clients need a price and payment challenge in the protocol flow, not a human checkout page or sales form.
Payment before access
SatGate verifies payment details before forwarding the protected API request upstream.
Scoped unlocks
Payment should unlock the requested route, tool, dataset, or capability — not a broad reusable API key.
Signed receipts
Every paid request should record delegated permissions, agent identity, route, price, payment proof, policy decision, and a signed receipt.
A governed L402 request flow
# Saturnzap CLI; any L402-capable client can present proof
sz fetch https://api.example.com/premium-research --max-sats 25
# SatGate replies with an L402 challenge
HTTP/1.1 402 Payment Required
WWW-Authenticate: L402 invoice=lnbc..., macaroon=...
# Delegated client presents proof and receives the resource
HTTP/1.1 200 OK
{ "answer": "paid premium result" }In this pattern, the merchant runs SatGate. The delegated client or wallet presents payment proof. Payment, authorization, receipt capture, and audit happen at the gateway before forwarding.
See agent demand
Understand which agents and routes create monetizable demand before forcing a pricing model.
Protect access
Limit which agents, routes, prices, budgets, and proofs are accepted before unlocking protected resources.
Preserve the receipt
Use L402 payment proof as one input to a signed receipt that records authority, rail, price, and decision.
FAQ
L402 payment rules questions
What are L402 payment rules?
L402 payment rules let an API return an HTTP 402 challenge while SatGate verifies delegated permissions, budget, scope, and payment proof before access.
Why use L402 for agent/API paid access?
Delegated agent/API access needs programmatic, low-friction payment proof. L402 combines HTTP 402, Lightning invoices, and access credentials while SatGate keeps authority, budget, and scope explicit.
Is L402 enough to govern paid agent access?
No. L402 is a payment/access rail. SatGate rules and receipts cover authority, scope, budget, revocation, and signed receipts.
What APIs are good candidates for agent/API paid access?
Premium search, data enrichment, research APIs, MCP tools, datasets, model endpoints, and delegated agent services are good L402 candidates when value is tied to each request.
How is L402 different from a normal API subscription?
A normal API subscription requires a human signup, plan, billing account, and long-lived key. L402 lets a delegated client receive a machine-readable HTTP 402 challenge, present payment proof, and unlock scoped access for the specific request.
Can payment details include budget and access policy?
Yes. SatGate can combine L402 payment proof with checks before the request goes through, covering identity, route, tool, quota, expiry, revocation, and audit, so paid access is still governed.
Related delegated paid-access guides
HTTP 402 for AI agents
Compare payment challenges, shared payment tokens, and L402 for autonomous agents.
Agent payment governance
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Stripe Link for Agents vs SatGate
See how payment credentials differ from SatGate spending controls.
Rules and Receipts
See how paid access becomes a signed receipt.
Govern AI agents
Govern paid agent actions before the call runs.
Agent capability tokens
Scope paid access with route, budget, expiry, delegation, and revocation caveats.
L402 protocol explained
How HTTP 402, Lightning, and macaroons enable API payments.
L402 API pricing calculator
Estimate per-request agent/API paid-access pricing.
AI agent governance
Limit delegated permissions before a payment method runs.
Govern L402-paid access with Rules and Receipts
L402 can prove payment. SatGate proves the action was authorized: who acted, what policy applied, which rail was used, what was paid, and why access was allowed or denied.