Wowcher is the second-largest provider of discounts in the United Kingdom. They handle traffic similar to what you’d see on ticket-selling websites during a major concert launch. With around 10 million members across the UK and Ireland, they can’t afford technical hiccups.
Wowcher came to us with three technical challenges affecting their operations: high email bounce rates risking their AWS account status, unstable Docker builds in their development pipeline, and outdated Jenkins agents with security vulnerabilities.
Let’s examine each of these challenges in detail, starting with the most urgent issue that threatened their ability to communicate with customers.
Wowcher faced a critical situation when their Amazon SES Reputation Bounce Rate reached an alarming 10.72%. If you’re not familiar with email systems, that’s dangerously high. Amazon was literally going to block the sending of emails from the entire production account! Their SES status was officially “At Risk” – not where any business wants to be.
We began with a review of their DNS records – including SPF, DKIM, and MX – which are essential for email authentication and proper routing. All configurations turned out to be fully correct. Then we set up proper logging so we could actually see what was happening when emails failed. We also implemented a Suppression List to prevent repeated sending to problematic addresses.
We created a “friendly email bot” that would send random short human-readable stories to verified email addresses at random intervals. This simulated natural email correspondence patterns that wouldn’t trigger spam filters.
These efforts successfully reduced the Bounce Rate to an ideal 0.00%, changing their account status to “Healthy” and eliminating the threat of mail account blocking.
Current bounce rate 0.00%
While sorting out the email situation, we noticed another headache the team was dealing with. Their Docker builds in Jenkins failed every time the shared base images disappeared from the cache.
In fact, the problem was the authorization method used for the Docker registry. This method did not allow logging in to two different private Docker registries at the same time – to pull a base image from one private registry and push the built image to another one.
We have analyzed and stabilized the interaction process, solving the main problems of authorization. This decision was important for Wowcher as the unstable CI/CD pipeline was slowing down releases and negatively impacting business processes.
After implementation, Docker cache clearing no longer caused build errors, resulting in a stable and reliable build process that helped streamline product releases.
Further assessment revealed that Wowcher was operating on outdated Jenkins agents based on CentOS 8 – software so old it wasn’t even receiving security updates anymore.
We executed a complete update of the Jenkins environment, transitioning to unified images based on official jenkins/inbound-agent. This required adapting and standardizing more than 300 pipelines for compatibility with both old and new Jenkins agents.
To make this manageable, we built a smart migration script that automatically handled most of the tedious work: cloning repositories, updating configuration files, creating pull requests, and even generating progress reports for management.
Our team successfully migrated 230 repositories without disrupting daily operations. The Wowcher team could finally breathe easy knowing their development environment was secure, predictable, and ready for the future.
The technical infrastructure optimizations we implemented transformed Wowcher’s development and delivery processes. Each solution built upon the previous one to create a more resilient system that supports their business operations.
With these improvements, Wowcher continues to provide reliable service to millions of users across the UK. Their development team can now focus on creating excellent user experiences rather than troubleshooting infrastructure problems.
Want to see the bigger picture?
This case study is just one chapter in our ongoing partnership. To get the full story of how we’ve been maintaining and optimizing Wowcher’s entire e-commerce system over the past 8 years, check out this case study: DevOps for Maintaining and Optimizing Wowcher’s E-commerce System.
