When Flooid, a leading unified retail commerce platform provider, rolled out a new loyalty (Clubcard)  for One Stop, they needed one thing to be certain: 

No matter how busy the stores got, the tills couldn’t slow down. 

Owned by Tesco, One Stop operates over a thousand convenience stores across the UK, so even a small delay at the till can quickly turn into long queues, frustrated customers, and lost revenue. Our job was to make sure that didn’t happen. 

The Challenge

Flooid had integrated a loyalty solution (Tesco Clubcard) into One Stop’s POS and Self-checkout systems. That meant every eligible transaction now needed to: 

1. Look up the loyalty account
2. Apply any offers or discounts
3. Record the transaction for points and reporting

All in real time, while customers were standing at the till. 

The performance target was clear:

• Support high volumes of transactions across a large estate
• Stay stable during peak trading periods (Christmas rush, seasonal promotions, and weekend spikes)
• Avoid any noticeable slowdown in the checkout experience

What We Did

We designed and executed end-to-end volume and performance testing for the loyalty integration:

• Modelled real-world peaks: Built realistic test scenarios mimicking true store behaviour, back-to-back transactions, and mixed basket sizes.
• Designed robust load tests: Progressively scaled load beyond typical peak thresholds to uncover edge-case system behaviour under sustained stress.
• Monitored end-to-end performance: Tracked response times across POS terminals, self-checkouts, middleware, and backend loyalty services to eliminate bottlenecks.
• Collaborated on tuning and fixes: Worked alongside Flooid engineers to guide capacity tuning and code-level optimisations.
• Validated against peak scenarios: Re-ran automated test suites to verify resilience under live retail trading conditions.