Payments

If you are building or operating a real-time payments platform in 2026, you already know that rules-based fraud detection is dead. Attackers use generative AI to produce thousands of synthetic identities per hour, payment rails like FedNow and SEPA Instant settle in under 10 seconds, and authorised push payment (APP) fraud alone cost UK consumers £460 million in 2025 according to UK Finance. The only way to keep up is machine learning operating at the wire — feature computation, model inference, and a decision returned before the payment completes. The modelling is the easy part. The hard part is building the infrastructure to serve those models at sub-100-millisecond latency, with features computed from streaming data, with rules and models running in the same decision pipeline, and with explainability that satisfies regulators. ...

In 2026, the fastest-growing customer segment in digital payments is non-human. AI agents are initiating, managing, and executing financial transactions autonomously — without a finger on a touchscreen, without a CVV entry, without a 3D Secure challenge. The IMF’s April 2026 working paper on agentic AI and payments made a sobering observation: current payment systems embed assumptions about human behavior at every layer. 3D Secure assumes you can present a challenge screen. Velocity checks assume a single human on a single device. Receipt delivery assumes someone will read an email. None of these hold when an AI agent makes the purchasing decision. Fenwick & West declared 2026 “the year of agentic payments.” The AI agent market is projected to grow at 49.6% CAGR through 2033. And fintech’s share of venture dollars hit 13.4% in Q1 2026 — its highest in three years. If your payment infrastructure doesn’t support AI agents as first-class customers, you are building for yesterday’s market. ...

Payment systems are the hardest type of event-driven system to get right. A misplaced message in a recommendation engine means a user sees the wrong product. A misplaced message in a payment system means money moves to the wrong account — and that is a regulatory incident with real financial consequences. We have designed and built event-driven payment platforms for fintechs processing hundreds of thousands of transactions daily. Here is the pattern that works. ...

Processing payments at scale is one of the hardest problems in distributed systems. Every transaction must be exactly-once, the system must be available 99.999% of the time, and reconciliation must be perfect. A payment gateway that processes 100 million transactions per month cannot afford to lose a single transaction or double-charge a single customer. We have built payment gateway infrastructure for fintechs processing over $10 billion in annual transaction volume. The architecture decisions that matter are not about speed — they are about correctness, idempotency, and the ability to recover from partial failures without losing money. ...