Agentic Payments (x402 + L402)
Design and integrate per-request payment for an API that AI agents will call. HTTP 402 done properly - wallet, custody, compliance, and abuse-defence answered before they bite.
4 weeks (2 sprints)
Who this is for
API-first SaaS, marketplaces, data providers, compute / inference / extraction APIs whose customers are increasingly using agent-driven access and need usage-based pricing for non-human callers.
When you need it
Your API is being called - or is about to be called - by AI agents on someone else's behalf. The user is no longer a human clicking a button; it's software with a budget. You want to monetize that traffic without dragging every agent operator through a sales call.
What's delivered
- Payment-model design: which endpoints meter, which stay free; per-request vs session-pass vs subscription gate
- Protocol selection: x402 (USDC on Base) as primary; L402 (Lightning) for Bitcoin-native or non-EVM constraints
- Wallet and custody: EOA vs smart account vs custody provider, key-management posture, off-ramp strategy
- Network and asset choice with reasoning written down for audit
- Facilitator selection: Coinbase CDP, self-hosted, third-party - with cost-per-verify modelling
- Server-side integration in your stack (Next.js, Express, FastAPI, Go, or other - named in Sprint 1)
- Pricing-model calibration against unit costs and competitor benchmarks
- Fraud, replay, and abuse defences: nonce, signature verification, replay-window, rate-limit-on-top-of-payment, blacklist hooks, refund posture
- MiCA / VAT / AML compliance scoping for counsel review (not legal advice)
- Monitoring and accounting: on-chain analytics, alerting, daily settlement, finance-stack integration
- Agent-discovery surfaces so callers know what to pay for: /.well-known/mcp.json.paidEndpoints, llms.txt, Link headers
- Board-ready summary including projected agent-revenue baseline and operational risk surface
Why this consultant
Monitive's own /api/agents/match endpoint is the live reference implementation of x402, including the facilitator integration, payment-required body shape, receipt header, and graceful-degradation path. Co-author of WARRANT Standard for autonomous agent authorisation - and agent-payment authorisation is the natural extension of agent-action authorisation. Compliance posture is built into the engagement because shipping x402 without it is a problem deferred, not avoided.
What this sprint is not
- Legal advice (compliance scoping is structured input for your counsel, not an opinion)
- Broader crypto / treasury / token / on-chain product strategy (scope separately)
- Custodial work (Monitive does not hold your funds, keys, or your customers' payments)
- A 1-day wire-it-up engagement (that's mini A20)
Fixed price, fixed scope. Every engagement carries the four guarantees: Sprint 1 Escape Hatch, Board-Ready Quality, Three-Client Cap, Skin-in-the-Game Pledge.