UK retailers face surge in untested code risks for Black Friday

Retail technology systems across the UK face increased risks of failure during Black Friday and Cyber Monday as retailers race to deploy new features and pricing engines under deadline pressure. Research shows that software teams are frequently deploying untested code, which could threaten the stability of online shopping platforms during peak periods of demand.

Risky code deployments

According to a recent survey, 40% of UK software teams admit to releasing code changes that are either risky or have not undergone sufficient testing, particularly as critical trading windows approach.

Over 80% report experiencing production incidents at least once a week, highlighting persistent challenges around digital reliability.

This pattern of risky software releases raises the likelihood of outages, checkout failures, and lost revenue during periods when every minute of uptime matters. During Black Friday and Cyber Monday, even a brief technical disruption could result in thousands of pounds in lost sales and erode customer trust.

Infrastructure stress tests

These shopping events now serve as a real-time stress test for retail IT systems. Retailers must make rapid changes to online discounts, inventory, and customer experiences. Engineering teams are under pressure to deliver new deployments and swiftly adjust systems, but this pace can jeopardise stability.

The risk is exacerbated by the high transaction volumes and consumer expectations tied to Black Friday and Cyber Monday, with little margin for error.

The consequences of downtime now extend beyond immediate sales to long-term brand reputation and loyalty loss.

Recommendations for resilience

Experts advocate several risk-mitigation strategies ahead of peak trading. Precautionary measures include extensive load testing at volumes three times higher than expected peaks, implementing instantaneous feature toggles to manage emerging incidents, and automating system recovery wherever possible to pre-empt customer-facing failures.

Retailers are also encouraged to audit key digital channels and third-party services, ensuring vital components such as payment gateways and email notifications are tested and have backup plans in place. Shifting away from blanket code freezes to progressive feature delivery is advised, providing incremental control over which users experience new changes and when they do so.

Industry response

Joe Byrne, Global Field CTO at LaunchDarkly, said,

"Black Friday exposes how fragile many digital systems still are. Retailers spend all year preparing for this weekend, yet too many are still gambling on unstable code and hope-for-the-best releases. Retailers who build resilience into every release - through testing, automation, and control will not only move fast, but recover faster."