Improving App Performance by 200%

Let’s talk about your project

Let's connect
Callstack Cosmos
Callstack Cosmos


In brief

We optimized the client’s mobile app performance and introduced a custom tool to measure performance regressions. We set up performance tests and documentation to enable a seamless transition of knowledge with the in-house team of developers.

Client Info
Entain is one of the world’s largest sports betting and gaming entertainment groups.
Commercial gaming
Company type
Australia, Asia & Oceania
Tech Info
Performance optimization project with the best practices, approaches & tech solutions
React Native | Native
iOS | Android
Redux | Tanstack | Reassure | GraphQL

Performance Boost


In 87.5% of the screens, the number of rerenders decreased or remained the same, which affected the acceleration of the initial performance.

React Universe

In brief

Leveraging tools like Lighthouse and Next.js functionalities, we significantly improved the app's performance, reducing loading times by at least 200%. The SEO improvements achieved exceeded the client's expectations, marking a successful collaboration that optimized the app for superior user and developer experiences.


AutoZone is a major player in automotive retail with almost seven thousand stores worldwide. It’s a huge e-commerce company operating through a complex application on mobile and web.

In a span of several months, our team effectively overhauled the AutoZone app's performance, which initially struggled on both desktop and mobile devices.


When AutoZone sought our expertise, the challenge was to address performance issues with their internal React Native apps, particularly the ones for delivery drivers and B2B auto parts ordering. 

As we delved into the project, our focus shifted to the AutoZone web app, already in development for two years with unsatisfactory performance. Recognizing the client's goal to improve web performance and SEO rankings on Google, we geared our efforts to help them achieve the desired results.


Working closely with the client's SEO team, we focused on Core Web Vitals metrics, including:

  • Time To Interactive, 
  • Largest Contentful Paint, 
  • First Contentful Paint, 
  • Cumulative Layout Shift with Time To First Byte 

Continuous monitoring with Lighthouse resulted in:

  • 200% improvement in app performance, 
  • faster loading times, 
  • and a significant boost in SEO rankings. 

Our efforts included optimizing a large shared JS bundle and leveraging tools like Bundle Analyzer and Source Map Explorer.


graph showing refresh time improvement

We improved web app performance by 200% and increased SEO rankings. We achieved these results by taking the following steps:

  • migrating from a custom server-side rendering (SSR) solution to Next.js, 
  • focusing on Core Web Vitals metrics, 
  • optimizing a large shared JS bundle, 
  • and introducing Fast Refresh for accelerated development iterations.

The introduction of Fast Refresh in Next.js further accelerated development iterations. All in all, it contributed to an enhanced user and developer experience.

The challenges we’ve solved so far

Related services


Optimization of Products and Processes

Callstack illustration

get in touch

Fill in the form and tell us a little bit about your enquiry. We’ll get back to you promptly to discuss your requirements.

Get in touch
This information will be used only to contact you. For details, check our Privacy Policy.