FinTech
How We Helped FinTech Startup Scale 10x
Client
Series A FinTech (Confidential)
Industry
FinTech
Services
Platform Architecture, Cloud Infrastructure, Engineering Leadership
Location
London, UK
The Challenge
The product had grown faster than the architecture beneath it. What started as a tightly-coupled monolith built for speed to market was now causing payment latency spikes under load, unpredictable performance during peak periods, and a deployment pipeline so fragile that a bug in one service could take down the whole platform. The engineering team was spending more time managing incidents than shipping features — and investor growth targets were at risk.
The catch: the product was live with paying customers. A full rewrite was off the table. What was needed was a phased migration that could decompose the monolith incrementally — starting with the highest-risk payment and identity services — while keeping the product stable throughout. The team also needed technical leadership: engineering processes, on-call structure, and architectural decision-making that would hold up as headcount doubled in the next twelve months.
The Solution
A phased microservices migration and cloud infrastructure overhaul — decomposing the monolith service by service, rebuilding the deployment pipeline, and providing embedded engineering leadership to take the internal team with us every step of the way.
Microservices Migration
Designed and executed a phased decomposition of the monolithic backend — extracting payment processing, identity, and notification services first, standing each up behind an API gateway with feature flags controlling cutover, and verifying parity before decommissioning the old code paths.
Cloud Infrastructure Overhaul
Re-platformed the infrastructure on AWS EKS with horizontal auto-scaling, multi-availability-zone redundancy, and a CI/CD pipeline that reduced deployment lead time from three days to under two hours — supporting 10x user load without a proportional increase in infrastructure cost.
Engineering Team Enablement
Embedded a fractional CTO and senior engineers for six months to build architectural decision records, introduce incident management processes, run architecture reviews, and upskill the internal engineering team — leaving a team that could own and extend the platform without continued external support.
- 10×User capacity growth achieved without rewriting the product
- 0 hrsUnplanned downtime during the entire migration
- -68%Reduction in payment processing latency under peak load
- 200K+Active users supported post-migration
- 8 moFrom initial scoping to full production cutover
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