Payments Systems at Scale: Lessons from Uber's Unified Platform
On the story of how Uber's engineering team transformed a maze of payment systems into a unified platform that powers millions of transactions daily
Picture this: You're at a restaurant that accepts credit cards for dine-in but only cash for takeout, Apple Pay for drinks but not desserts. Sounds absurd? This was essentially Uber's reality across its services.
As Uber evolved from a simple ride-hailing app into a super-app offering food delivery, grocery shopping, and even car rentals, each new service built its own payment system. The result? A labyrinth of 70 different payment endpoints, each speaking its own language.
This fragmentation created real-world headaches. A user could pay for an immediate ride with Apple Pay but couldn't use it for a scheduled pickup. Popular payment methods like PIX (Brazil) and UPI (India) worked inconsistently across services. For any new payment feature or compliance requirement that needed to be integrated, engineers would have to spend countless more hours maintaining this new duplicate code.
The cost wasn't just technical. When the European Union mandated Strong Customer Authentication for transactions, requiring features like fingerprinting and biometric verification, it became clear: Uber needed to revolutionize its payment infrastructure or risk losing hundreds of millions in revenue.
Unified Checkout - One Gateway to Rule Them All
What Uber’s engineering team created is a payment universal translator, which they called Unified Checkout. The way it works is that instead of each service (rides, eats, rentals) handling payments differently, everything flows through one complex system.
This payments orchestration layer while it helps to process millions of transactions and to maintain consistency across all services, it keeps individual services blissfully unaware of the underlying complexity.
The architecture revolves around a chain of microservices that handle everything from payment profile preparation to risk evaluation. When a user starts a transaction, the platform exchanges transactional data with third-party processors, generates authentication tokens, and coordinates with risk systems to determine the optimal payment strategy. The system is able to adapt its approach based on the risk algorithms, whether if it’s for an authorization hold or an upfront charge.
One notable capability of the Unified Checkout is that it provides two distinct integration paths.
The modular approach allows services to embed pre-built components into their existing checkout flows, maintaining their unique user experience while leveraging the unified payment infrastructure.
For newer or smaller services, the hosted solution provides a complete out-of-the-box payment experience, accelerating time-to-market without compromising on functionality.
Another key advantage is the "Checkout Actions" framework - a stateless system that orchestrates complex payment flows, from two-factor authentication to identity challenges, this framework handles every possible payment scenario while maintaining a consistent user experience.
By treating each Uber service as an external company, the platform maintains strict boundaries between payment logic and business operations. This architectural decision forced the team to build a solution that could handle any payment scenario while remaining service-agnostic, and hence building a good foundation for future payment innovations.
The Business Impact
The Unified Checkout delivered a remarkable 3% increase in checkout conversion rate and a 4.5% improvement in session recovery, which meant saving hundreds of millions in additional annual revenue. These results were shown in an experiment on UberEats, where the team compared user behaviour between the old and new systems, leading to rapid adoption across all services.
This transformation dramatically simplified the payment landscape at Uber. Adding another payment method like Apple Pay doesn’t require a full implementation anymore, but only some configuration changes. Moving away from 70 endpoints to one single unified system streamlined operations and changed on a fundamental level how Uber does payments. Duplicate development work vanished. The launch of new payment methods accelerated dramatically. A consistent user experience across services built stronger trust with customers. Payment method decisions shifted from technical limitations to pure strategy, allowing Uber to optimise its offerings based on market needs rather than implementation constraints.
Maintenance costs plummeted as teams no longer needed to maintain multiple implementations. Compliance became more straightforward, error rates dropped significantly, and customer support issues decreased. And probably most importantly, new services could now launch faster, equipped with a complete payment infrastructure from day one.
Lessons Learnt
It comes a time in a company’s scaling journey where maintaining multiple systems becomes more expensive than building a unified platform. For Uber, this moment came when they faced 70 different payment endpoints across their services, each requiring separate maintenance and updates.
Uber's experience demonstrates how external pressures, like EU regulations, can serve as catalysts for positive change. What began as a compliance requirement evolved into a platform that generated hundreds of millions in additional revenue.
Looking toward the future, the key is creating modular systems that can evolve with changing requirements, while maintaining a clear separation between business logic and payment processing. This separation allows for easier updates and maintenance as regulatory requirements change or new payment methods emerge.
The most valuable lesson from Uber's journey is recognizing that technical debt isn't always a burden – it can be a signal that your system is ready for platformization. When multiple teams struggle with similar problems, it might be time to step back and consider a unified approach.
The Uber article is available here:
Unified Checkout: Streamlining Uber’s Payment Ecosystem