At the XT25 Fintech Conference, Donato Lucia, Partner and Head of Technology at Revolut, delivered a compelling talk titled: Taming Complexity in Distributed Systems: What’s Behind Revolut’s Success.
Donato shared insights from Revolut’s hypergrowth journey from 1M customers in 2017 to over 55M in 2025 and the corresponding explosion in technical scale: thousands of services, hundreds of database clusters, and a global engineering team of over 1,400.
His central theme: while complexity is inevitable, accidental complexity isn’t. By adopting a convention-based architectural framework, Revolut has been able to manage scale, improve reliability, and move faster without compromising resilience.
Key lessons included:
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Constraining choices reduces entropy and speeds up design decisions
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A well-defined service topology (frontend APIs, flows, states, gateways, ML, event stores) creates clarity and consistency
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Framework invariants (restricted integrations, minimal delegation, encapsulation, and gradual evolution) prevent chaos in distributed systems
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Clear scalability levers (read/write separation, stateless flows, auto-scaling) and resilience levers (timeouts, retries, secure boundaries) keep systems robust under load
Donato concluded with a powerful takeaway:
Structure enabled scale — not the other way around.
Watch the full talk here:
Access Donato’s slides here.
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