How We Rebuilt and Optimized Our Client's iOS App to Overcome Performance Challenges

The importance of having a high-performing, scalable, and secure application is obvious to business stakeholders. Unfortunately, even with a development team in place, product quality can suffer—delays in delivery, subpar performance, and poor execution can hold back growth and frustrate stakeholders. This was the case with one of our clients, who approached us with significant issues in their iOS app. Their internal team was struggling to meet deadlines, and the app was riddled with performance bottlenecks, bugs, and a lack of consistency in the codebase. Worse, they were spending too much time firefighting rather than innovating.

Understanding the Pain Points

Before diving into the technical recovery, we needed to understand the core issues the client was facing. Like many other teams, their developers were:

• Struggling with slow development and delivery times: The app was taking far too long to build and release. Every new feature seemed to introduce new problems, which took even longer to fix.
• Lacking a robust CI/CD pipeline: Releases were still being managed manually, which not only delayed deployment but also led to errors and inconsistencies. This dependency on manual processes added stress and uncertainty, often requiring significant effort from key developers.
• Dealing with a fragmented, outdated codebase: The project was a mix of Objective-C and Swift code, with parts that hadn’t been touched in years. The codebase was difficult to maintain, and understanding how different components interacted was a challenge. This slowed down the team’s ability to deliver features or address bugs quickly.
• Suffering from poor product stability: The app’s crash-free rate was unacceptably low, and regressions in stability were common. These issues significantly impacted user experience and ultimately the product’s reputation.
• Facing a shortage of testing coverage: Without proper unit and integration tests in place, the team was left guessing whether new features would introduce critical bugs.

The challenge was clear: they needed a plan that could systematically address these issues, improve team performance, and ensure the app was ready to scale.

Our Recovery Plan

We started by designing a phased plan to address the most critical issues while ensuring that development could continue smoothly. Our plan focused on three main areas: optimizing the codebase, implementing a strong CI/CD pipeline, and improving testing and stability.

1. Refactoring and Modernizing the Codebase
   • We began by cleaning up the legacy Objective-C code, transitioning critical components to Swift. This was not about rewriting everything at once—that would have been impractical and costly. Instead, we identified key areas where refactoring would deliver the most value and improve maintainability.
   • We removed unused and deprecated code that was cluttering the project, which made it easier to work with and reduced the complexity of the overall codebase.
   • As part of the refactor, we established a consistent architecture and naming convention to ensure all developers were aligned on best practices moving forward.
2. Streamlining CI/CD Processes
   • One of the most significant issues was the lack of automated testing and deployment. We implemented a robust CI/CD pipeline using GitHub Actions to automate the build, testing, and deployment processes. This drastically reduced manual errors and freed up developers to focus on feature development rather than firefighting.
   • We integrated tools like SwiftLint and SwiftFormat to ensure code quality was maintained, and every pull request now triggers automated tests to verify the build’s integrity.
3. Improving Testing and Stability
   • To address the app’s poor stability, we introduced unit testing across key components and established standardized testing processes for every new feature. We also added integration tests to ensure that changes didn’t introduce regressions in other parts of the app.
   • The crash-free rate of the app improved dramatically. By Q2, we had exceeded our goal, reaching a crash-free rate of over 90%, up from 80% at the start of the project.

Results That Matter: Speed, Quality, and Stability

The effects of these changes were profound. Over the course of two quarters, we saw measurable improvements across all key metrics:

1. Faster Releases and Increased Delivery Velocity
   • We doubled the frequency of releases. In Q1, the client was only able to release once per month, but by Q2, they were on a two-week release cycle. Not only were releases faster, but they were also delivering more significant user-facing changes:
     • Q1: 9 major changes delivered
     • Q2 (mid-quarter): 12 major changes delivered, with more expected by the end of the quarter
   • The development team’s velocity also increased, with the average story points per sprint growing steadily as the codebase became easier to work with.
2. Improved Product Stability
   • Our work on testing and bug fixes significantly reduced the number of bugs reported by users. Over 22 critical bugs were fixed, improving the user experience dramatically. Additionally, we had zero release rollbacks due to regressions in Q2, a first for the team.
3. Higher Developer Productivity and Morale
   • With a cleaner, more maintainable codebase and automated processes in place, the development team was able to focus on delivering new features rather than dealing with bugs and manual deployment issues. Developer morale improved as they were no longer bogged down by firefighting, and they could see tangible progress in the quality and stability of their work.
4. Better User Experience and Satisfaction
   • The significant improvement in the app’s crash-free rate contributed to a better overall user experience. Both internal stakeholders and users reported a noticeable difference in the app’s performance and reliability, leading to higher user satisfaction and a stronger product reputation.

Conclusion: A Foundation for Long-Term Success

By addressing the technical debt in the client’s iOS app and implementing a structured recovery plan, we helped them overcome performance bottlenecks and improve their delivery speed and product quality. The key to our success was balancing technical improvements with business goals—focusing on changes that would reduce complexity, improve stability, and enable the team to scale.

If your team is facing similar challenges with poor execution, slow delivery, or a lack of stability, we can help. Reach out to us to learn how we can optimize your product and boost your development performance.