Peak Performance: Preparing Platform for Key Trading Period Surges
How Moonpig partnered with Build Circle to stress-test and optimise platform infrastructure for holiday surges, increasing order-per-minute throughput by over 50% and driving a 50% performance uplift through the checkout funnel.
"Build Circle has been a great technology partner working as an integrated part of our engineering teams. They’ve helped deliver multiple strategically important projects to set Moonpig up for the next phase of growth. I would highly recommend them to anyone looking for support with delivering complex projects."
CTO, Moonpig
Increase in orders/min capacity handling extreme concurrent volume
Order funnel performance uplift speeding up personalisation to checkout
Unplanned downtime sustained through peak Valentine's & Mother's Day
Peak trading sales achieved exceeding all historical benchmarks
The Challenge
Mitigating massive revenue risk during peak holiday traffic surges
For a high-volume personalised gifting platform like Moonpig, commercial success hinges on an exceptionally concentrated set of trading windows. Critical holiday events such as Valentine’s Day and Mother’s Day generate extreme traffic spikes, compressing a significant percentage of annual consumer demand into narrow, multi-day intervals.
During these trading periods, any performance latency, checkout failure, or system downtime results in immediate, irreversible revenue loss:
- Untested high-concurrency limits: Moonpig’s core platform infrastructure had not yet been validated against the extreme traffic ceilings anticipated for upcoming peak seasons.
- Hidden bottlenecks: System bottlenecks under massive, concurrent user load were likely across the browse, personalisation, and checkout pathways, but were difficult to isolate without specialised testing.
- Cart abandonment vulnerability: Slow rendering speeds or latency during checkout directly threatened conversion rates when consumer traffic was at its highest.
Moonpig needed a comprehensive performance engineering and load-testing initiative to uncover structural constraints, remediate latency, and ensure the platform could scale under surge traffic without latency or failure
The Solution
Rigorous load simulation, observability, and iterative remediation
Build Circle partnered with Moonpig’s technical teams to architect, execute, and monitor end-to-end stress-testing protocols across the entire customer journey:
1. High-volume traffic simulation
- Synthetic load frameworks: Built custom load-testing suites designed to accurately simulate real user journeys at unprecedented concurrency levels.
- Full-funnel stress testing: Validated system resilience across every stage of the transaction lifecycle, including search, image customisation, dynamic card rendering, and payment gateway calls.
2. Observability & bottleneck identification
- Real-time strain monitoring: Deployed advanced telemetry and platform performance monitoring tools to observe real-time database locks, server utilisation, and API latency under simulated surge volumes.
- Precision diagnostics: Pinpointed the exact architectural thresholds where throughput degraded, identifying previously undetected performance bottlenecks.
3. Iterative optimisation & hardening
- Targeted platform tuning: Implemented iterative software and infrastructure fixes to decouple services, optimise database read/write queries, and reduce data serialisation overhead.
- Continuous DevOps improvements: Automated performance validation within deployment workflows, ensuring future releases maintain strict latency and throughput thresholds.
Business Outcomes
Flawless platform resilience and all-time record sales
- Record-breaking peak sales: Moonpig comfortably surpassed previous commercial benchmarks, capturing maximum peak revenue without operational interruptions.
- 50%+ surge in transaction capacity: Scaled platform throughput to process over 50% more orders per minute, eliminating lag, queue delays, and checkout timeouts.
- 50% faster order funnel: Drastically collapsed page loading, asset customisation, and payment processing times, delivering a fast checkout experience that minimised cart abandonment.
- 100% availability under maximum strain: Maintained flawless, zero-downtime stability across the entire duration of Valentine's Day and Mother's Day trading windows.
- Permanent performance foundations: Left the internal engineering organisation equipped with automated performance-testing frameworks and observability tools to protect all future seasonal surges.
Preparing for major commercial spikes or high-traffic trading windows?
Discover how Build Circle’s performance engineering teams help high-scale digital leaders stress-test platforms, eliminate bottlenecks, and ensure uninterrupted transaction flow.
Contact us_
Whether you’re modernising, migrating, scaling, or strengthening resilience, we’ll help you deliver faster, safer, and with stronger teams.
Let's talk about your roadmap.
