What is AP2
Agent Payments Protocol (AP2) is Google’s open protocol for AI agents to negotiate, authorise, and settle payments on behalf of humans. Unlike x402’s per-request model, AP2 introduces mandates: signed, scoped authorisations a human gives an agent. For example, “you may spend up to $50 buying flights from these vendors”. AlgoVoi provides the on-chain settlement extension for AP2. When a mandate is exercised, the resulting payment lands on Algorand, VOI, Hedera, Stellar, Base, Solana, or Tempo as USDC.When to use AP2
Bounded autonomy
“Buy any of these 5 SKUs under $20 each, max $100 total this week.”
Cross-vendor mandates
One mandate authorises an agent to pay multiple vendors without re-confirmation.
Audit-grade commerce
Every transaction traces back to a signed human mandate, giving you a strong audit story.
Human-present scenarios
Agent proposes, human approves once, then the agent executes without further approvals.
How AP2 differs
| x402 / MPP | AP2 | |
|---|---|---|
| Authorisation | Per-payment | Mandate (multi-payment, scoped) |
| Counter-party signing | Just the payer | Both human and agent |
| Settlement | Direct | Direct (with extension) |
| Best for | Unattended API calls | Agent-mediated purchases |
Sample scenarios
AlgoVoi has shipped two reference scenarios upstream into the official AP2 samples repo:crypto-algo human-present
Algorand USDC settlement of an AP2 mandate, with full agent and ADK code.
crypto-solana human-present
Solana Pay reference-binding settlement of an AP2 mandate.
Architecture
AlgoVoi sits in the verifier role, the same as in x402, but the agent is now spending against a pre-signed mandate rather than per-call human approval.Live demos
A working AP2 over A2A v1.0 REST + MCP demo runs against AlgoVoi’s production gateway. The agent card publishes:verify-paymentskill (AP2-compatible verification)create-checkoutskill (agent-initiated AP2 mandate exercise)check-statusskill