Your code has never charged you a dime. This changes that.
Every time an AI agent calls your API and you don't charge it, you paid for it - the compute, the inference, the bandwidth. Free. Forever, until now.
HTTP 402 - "Payment Required" - was reserved "for future use" in 1997, and it almost never got used. Until now.
Why this matters right now
Until recently, the internet only knew how to charge humans: cards, subscriptions, checkouts. An AI agent doesn't have a card, doesn't open a cart, doesn't wait 3 days for an invoice to get approved. It needs to pay the instant it decides to use something, with no person watching.
x402 is the protocol that finally solves that: an agent calls your API, your API answers "402, this costs 0.02 USDC", the agent pays right there, and gets its response in seconds. No account, no contract, no friction. It's already happening on mainnet.
Who this is for
If you code
You leave with a real repo: an API that charges, an agent that pays, and a verifiable receipt. Not notes - running code.
If you don't code yet
No session assumes you already know blockchain. If you follow basic logic, you'll understand every step - and see firsthand where the agent-run internet is headed.
What you'll build
Your API charges
0.02 USDC before it answers a single request. No card, no invoice, no human in the loop.
An agent pays
on its own, inside a spending limit you set. Nobody approves each payment by hand.
A receipt proves it
signed and anchored, that anyone can verify - no one, including us, can fake it.
100% on Stellar testnet. Test money, zero real risk. If you break something, nothing happens - that's the point of a sandbox.
If you already know how to code - basic JavaScript, no blockchain background needed - you can do this. You don't leave with notes. You leave with your own public repo, working.
What you'll actually learn, session by session
- How a Stellar payment works end to end, with no middlemen
- How to make any endpoint in your API charge per use, with the x402 protocol
- How to give an AI agent a spending limit it can't go around
- How to anchor a receipt anyone can verify, without trusting you
- How to read and check a payment directly on the network, without a third-party dashboard
5 sessions + Demo Day
First Stellar payment. Charging for an API with x402. An agent that pays on its own, inside a spending limit it cannot go around. Verifying a payment via RPC or Horizon, with Nirium as the real case study. And a Demo Day where you show what you shipped.
What you could build next
An API that pays for itself
Any service of yours - data, compute, your own model - billed per call, no Stripe, no monthly plan.
An autonomous buying agent
A bot that finds the best price, pays, and delivers the result - with no human approving each transaction.
A machine-to-machine marketplace
Agents buying and selling services from other agents, 24/7, with no office or schedule.
Verifiable invoicing for freelancers
Receipts a client can check themselves, instead of just taking your word for it.
Hosted by the Blockchain Acceleration Foundation, taught with Nirium - payment and audit-trail infrastructure for AI agents that has settled real x402 payments on Stellar mainnet (latest: 29 Sep 2026).
A Soroban contract that batches these receipts into a single verifiable anchor. Not built yet - it is part of our roadmap.
You do not have to take our word for it. Check a real receipt right now.
Verify a real receiptIn progress: Nov 10-27, 2026.
See the event