All 54 articles, sorted alphabetically
3-D Secure architecture
Deep-dive on EMV 3-D Secure (3DS2): the three domains, 3DS Server / Directory Server / issuer ACS, risk-based frictionless vs challenge decisions, dev…
Read article →Agent payments (AP2) architecture
Deep-dive on AP2 agent payments: signed mandate, issuer, acquirer, settlement, reconciliation, refund path, audit.
Read article →Authorization holds
Deep-dive on the payment authorization-hold lifecycle: authorizing to reserve funds and lower available balance, fulfilment and capture, partial captu…
Read article →AP2 chargebacks -- disputed agent payments and reversals
Deep-dive on AP2 chargebacks: the disputed-agent-payment problem, the chargeback flow (dispute to reversal), the mandate as authorization evidence, li…
Read article →AP2 Chargeback Handling
Disputes evidence and the merchant burden.
Read article →AP2 Compliance Landscape
PCI scope GDPR and regional rules.
Read article →AP2 Currency Conversion
FX rates timing and float exposure.
Read article →AP2 Disputes
How AP2 handles disputes when users challenge payments made by their agents.
Read article →AP2 dispute architecture
Deep-dive on AP2 dispute handling: filing, evidence collection, merchant response, arbitration, decision, signed reversal, feedback loop.
Read article →Double-entry ledger architecture for agent payments
Deep-dive on the double-entry ledger as the system of record for AP2 agent payments: the balancing invariant (debits equal credits), the append-only j…
Read article →Dunning management architecture
Deep-dive on dunning management for recurring payments: how a failed subscription charge enters a retry state machine that recovers involuntary churn …
Read article →AP2 escrow
Deep-dive on escrow for agent payments: the buyer-hold-condition-release flow, the oracle problem for condition verification, timeout and arbitration …
Read article →Fraud and risk scoring for agent payments
Deep-dive on fraud detection for agentic payments: mandate-chain verification, online feature stores and velocity counters, rules engines plus ML scor…
Read article →AP2 Fraud Signals
What looks like an agent and what looks like an attack.
Read article →AP2 FX conversion architecture
Deep-dive on foreign-exchange conversion in an AP2 agent payment: a rate source plus disclosed spread locked into a quote with an id and expiry, autho…
Read article →Idempotency keys in agent payments
Deep-dive on idempotency for AP2 payment requests: a client-minted key that makes a charge safe to retry any number of times with exactly one effect. …
Read article →AP2 Payment Intent Architecture in Depth
A 2500-word walkthrough of AP2 payment intent: structured intent, evidence, user review, signed intent, wallet + fraud, execution, receipt, dispute pa…
Read article →AP2 KYC
How AP2 handles KYC (Know Your Customer) requirements when agents transact on user's behalf.
Read article →AP2 KYC architecture
Deep-dive on KYC for AP2-style payments: identity verification, risk score, refresh, sanctions, jurisdiction, monitoring, audit.
Read article →AP2 mandate architecture
Deep-dive on AP2 payment mandates: intent mandates scoping the spending envelope, cart mandates authorizing transactions, user/agent signatures and ve…
Read article →AP2 Marketplace Settlement
Connected accounts and per-party splits.
Read article →AP2 Multi-Party Settlement
Splits, marketplaces, and the orchestration burden.
Read article →AP2 multiparty architecture
Deep-dive on AP2 multiparty payments: signed intent, split rules, escrow, fulfillment, per-party settlement, tax, refund + reversal.
Read article →Agent Payments Protocol (AP2) Overview
What Google's AP2 protocol is, why AI agents need programmatic payment capabilities, and how it extends A2A.
Read article →Agent Payments Protocol Architecture in Depth
A 2500-word walkthrough of AP2/agent payments architecture: intent, approval, wallet, fraud policy, payment rail, receipt, dispute, ledger, and regula…
Read article →AP2 Payment Flow
The step-by-step payment flow in AP2: request, authorization, token, capture, settle.
Read article →AP2 Payment Intent Flow
How agents authorize, charge, and reconcile.
Read article →PCI scope reduction architecture
Deep-dive on shrinking the cardholder data environment: why scope follows data flow, hosted fields and the same-origin boundary, PSP vaults vs network…
Read article →AP2 Pricing Signals
How AP2 exposes structured pricing so agents can shop and compare across merchants.
Read article →AP2 Payment Rail Architecture in Depth
A 2500-word walkthrough of payment rails in AP2: cards, ACH, wire, real-time (RTP/FedNow), crypto; cost + speed + reversibility trade-offs.
Read article →AP2 receipts -- verifiable proof of a completed payment
Deep-dive on AP2 receipts: the proof need, receipt contents (amount, parties, mandate reference, settlement), cryptographic signing, verification, lin…
Read article →AP2 payment reconciliation architecture
Deep-dive on reconciling agent-initiated payments: normalizing internal ledger, processor, and bank records into a canonical schema, tiered exact/fuzz…
Read article →AP2 recurring payments architecture
Deep-dive on AP2 recurring payments: signed mandate, schedule, charge event, dunning, change, cancellation, compliance.
Read article →AP2 refunds -- returning money for an agent payment
Deep-dive on AP2 refunds: the return-money need, refund (cooperative) vs chargeback (disputed), linking to the original payment/receipt, full vs parti…
Read article →AP2 Security
The threat model for AP2 (token theft, agent compromise, merchant fraud) and how the protocol defends.
Read article →AP2 Settlement
How AP2 payments actually settle: which payment rails, timing, and reconciliation.
Read article →AP2 settlement architecture
Deep-dive on AP2 settlement pipeline: signed intent, authorization, capture, reconciliation, reversal, ledger, dispute, and compliance.
Read article →AP2 split payment architecture
Deep-dive on split payments in an agent commerce protocol: a single buyer authorization and capture fanned into exact per-payee shares by an allocatio…
Read article →AP2 stablecoin architecture
Deep-dive on AP2 stablecoin payments: issuer, reserves, custody, chain settlement, signed intent, compliance, fees, reversal, audit.
Read article →Payment tokenization for agents
Deep-dive on payment credential tokenization in agent-payments architectures: token service providers and the token vault, domain restriction controls…
Read article →AP2 Tokens
How AP2 tokens represent authorized payments, their scoping, and their single-use / short-lived semantics.
Read article →Payment velocity limits architecture
Deep-dive on velocity limits for payments: multi-key extraction, windowed atomic counters, sliding windows and distinct-count dimensions, a data-drive…
Read article →AP2 Verification
How AP2 verifies user identity, agent authority, and payment authenticity across the flow.
Read article →AP2 Wallet
How the AP2 wallet holds user's payment methods and issues tokens for authorized payments.
Read article →AP2 wallet architecture
Deep-dive on AP2 wallet: key custody (HSM/enclave), signing, recovery (shards/seed), hardware backing, multi-sig, session keys.
Read article →