Meridian Retail
Replatforming commerce ahead of a 4x peak
Peak handled at 4.1x prior-year volume with no degradation. Checkout p95 latency improved from 2.4s to 610ms.
- peak volume, no degradation
- 4.1x
- checkout p95, from 2.4s
- 610ms
- big-bang cutovers
- 0
Problem
A monolithic commerce platform that had degraded through each of the last three peak trading periods, with no path to scale the checkout independently.
Solution
Incremental extraction of checkout, inventory and pricing into separately scalable services, with the monolith left serving everything else.
Result
Peak handled at 4.1x prior-year volume with no degradation. Checkout p95 latency improved from 2.4s to 610ms.
Meridian had been quoted an 18-month full replatform by two firms. Peak was in nine months. The plan had to fit the calendar that actually existed.
How the work ran
- Checkout extracted first, because it was the component that failed and the one with the clearest boundary.
- Inventory and pricing followed, each behind a facade so the monolith kept calling the same interface throughout.
- Load testing at 5x projected peak from month three onward, not as a final gate.
- The remaining monolith left deliberately in place. It was not the problem and rewriting it would have been.
What made the difference
Most of the value came from choosing three components and refusing to touch the rest. The full replatform is still not done, and Meridian has not needed it.
“Senior people stayed on the work from the first workshop to production cutover. That is rarer than it should be and it showed in the quality.”
Arjun Mehta
Group Head of Digital, Meridian Retail