No one likes a sluggish application. Each and every one of us has experienced an unresponsive application at least once. It’s not great, and when it happens repeatedly or at the wrong moment – sometimes the first impulse is to delete the app altogether. Now, as an iOS developer that is not great news.

Yes, performance issues are just a part of it, but failing to solve them in time might result in two of the following things:

• Users will abandon your application in favor of competitors due to frustration.
• Reaching success will be much, much harder due to the strong competition in the field.

To avoid these consequences (let’s get serious)  and keep your users satisfied, I’d recommend researching ways on how you can optimize your iOS application in 2024 since the trends are everchanging. I’ve compiled a list of 25 best practices that, in my opinion, might be useful for both beginners and experienced developers and/or business owners. Without further ado, let’s get right into learning about these strategies!

1.Minimize Network Requests with Caching

The main culprit for delayed app response is often excessive network requests. But the solution is easy. Caching techniques can help minimize network calls, by frequently requesting data locally (for example, images) which takes the need for multiple downloads to a minimum. This will help you free up server load and in turn speed app the loading time of your app.

2. Asynchronous Operations with Grand Central Dispatch (GCD)

For a seamless user experience, the main thing you need to do is remove time-consuming operations from the main thread, and  Grand Central Dispatch (GCD) is perfect for making your app function effectively in the background. It’s still one of the most popular methods used to optimize performance because it performs non-UI tasks asynchronously. This ensures that the UI stays responsive even during activities that rely on heavy resources.

3. Optimize Image and Asset Sizes

This kind of goes with my first point. When optimizing, you can’t forget about compressing the size of your assets, including images. Why? Because the larger the size, the slower your app will run, and the opposite will improve your app's overall efficiency and loading time. In this case, to avoid sacrificing quality I prefer to use formats such as WebP.

4. Implement Pagination for Data Display

Big data sets are infamous for slowing down loading. This happens because quite often the app is made in a way where all the data is loaded at once. Here, pagination comes to the rescue. Pagination is loading data in small chunks, so as the user navigates across the application or interacts with it, data loads gradually.

5. Use Core Data for Local Data Storage

This is a strong and effective foundation for local data storage. Core Data stores your data permanently, and when you need it – you can retrieve it. Then, the software becomes more responsive even when the user is not online and less dependent on network calls.

6. Employ Advanced Compiler Optimizations

Xcode's advanced compiler optimizations are a great way to boost efficiency. Through things like Objective-C's inlining and Swift's whole-module optimization, you can achieve much faster code execution and even optimize memory consumption in your app, and routine code inspections will help you see if your code is operating at its peak performance – or not.

7. Reduce View Hierarchy Complexity

No one wants a complex view hierarchy to make an app less responsive. Flat-view hierarchies result in better animations and faster rendering times, so I’d say, reduce the number of subviews and eliminate superfluous nesting to simplify the whole thing.

8. Use Auto Layout Wisely

Auto Layout really does make it easy to create responsive user interfaces. But if you don’t use it correctly it can actually negatively affect performance. Try to prioritize intrinsic content size and stay away from undue restrictions. In fact, if you want to go even further stack views could also be a solution.

9. Profile and Debug Performance Regularly

Ah, regular profiling and debugging, a developer’s best friend. If you do this often, finding things that snag performance and also memory leaks will be an easy task. You can use the instruments in Xcode to check how your memory is used and allocated, and the more up-to-date you stay with this information, the more likely you can catch and fix the issue on time.

10. Opt for Swift Over Objective-C

Swift is generally considered the better choice for developing new iOS apps. It is meant to be quick and efficient and boasts a ton of cutting-edge features that can improve the responsiveness of your app. So, my advice would be to slowly transition from Objective-C to, let’s say, Swift.

11. Background Task Management with Background Modes**

While the application is not at the forefront, you can use iOS background modes (audio, location, background fetch) to help the app effectively handle tasks. This way, the important operations will continue running in the back without compromising the responsiveness of the app.

12. Implement Smart Prefetching

With this you can actually somewhat predict user behaviors and preload relevant data. Fetching and caching data in the background by analyzing user behavior and forecasting future actions, reduces loading times and offers a smoothee user experience.

13. Optimize Battery Consumption

This is a tricky one that even the most seasoned developers often tend to overlook. The responsiveness of apps and user satisfaction both depend on how effectively you manage battery power, the use of which you can reduce by staying away from resource-intensive or continuous processes. More energy-efficient algorithms and routine checks for parts that are likely to deplete the user battery will streamline the user experience.\

14. Utilize Content Delivery Networks (CDNs)

To speed up content delivery by lowering latency and delivering material closer to the user's location through caching CDNs (content delivery networks) are a great option. You can speed up performance by using the,, because they can host static content, such as images and videos, which is especially great for users in various geographic locations.

15. Stay Updated with the Latest iOS SDKs and APIs

Apple often releases new SDKs and APIs with iOS App Performance Optimization and enhancements that can be helpful in your optimization journey. Keep up with them! This way you can use the latest iOS tech for your app and guarantee that your app will stay compatible with the newer gadget models.

16. Reuse and Lazy Load Views

To use less CPU and memory, act like UITableView and UICollectionView and refrain from creating every subview all at once. Rather, try generating your views as you go and place them in a reuse queue whenever you're done with them. This way you may avoid the sometimes costly allocation and only have to set your views during the scrolling process.

Let’s consider a scenario in which a view must be displayed when a button is tapped by the user:

• When the screen initially loads, create the view and hide it. Then, when you need it, reveal it.
• Until you need to display the view, take no action. Next, generate the view and present it simultaneously.

The first option uses more RAM as it creates the view right away, retaining the data until it is released. Since your app only has to alter the view's visibility when the user taps the button, it will look more responsive. The second strategy will have the reverse effect; you will use less memory because the view is only created when necessary, but the application will not respond as quickly when the button is tapped.

17. Cache, Cache, Cache

When creating your app, it's a good idea to "cache what matters" – meaning items that are often requested but are unlikely to change. These types of cacheable resources include photos, calculated values like UITableView row heights, and remote server answers.

NSURLConnection already maintains disk or memory caches based on the HTTP headers it parses. You may also manually build an NSURLRequest with the option to only load items that are cached.

18. Consider Drawing

In iOS, when you set out to create visually appealing buttons, you’ve got two choices: use full-sized or resizable pictures, or go beyond and sketch it by hand with Metal, CoreGraphics, or CALayer.

Each one of these varies in complexity and performance, but the consensus is: pre-rendered graphics are quicker to use since iOS doesn't need to produce an image and then draw shapes on it. The problem with that is, that adding those pre-rendered images will inevitably affect the size of the app. Thankfully, iOS can automatically remove "wasted" image space, employing resizable photos is a wonderful way to optimize.

19. Handle Memory Warnings

When there is not enough system memory, iOS will alert all running apps. If you are on the receiving end of this notification, you have to make sure to free up as much space as possible for your application. Strong references to caches, image objects, and other data objects that can be easily recovered later should be removed to implement this step. Otherwise, the system will just halt your app. Remove them with thought, and make sure you can easily retrieve them in the future.

In the midst of working on your app, you can test this scenario by using the iOS simulator's Simulate Memory Warning function.

20. Reuse Expensive Objects

NSDateFormatter and NSCalendar are two things that take a very, very long time to initialize. But sometimes, like when processing dates from a JSON/XML response, you can't just ignore the lengthy process of utilizing them.

If you can apply this in your case, try reusing these objects while working with them to prevent performance bottlenecks by either making a static variable or by giving your class a property.

21. Use Sprite Sheets

A sprite sheet is a bitmap image file in computer graphics that consists of several smaller visuals merged into a tiled grid structure. By combining many visuals into a single file, you may use them in multiple applications with only one load. When performance is really important, like in game development, this efficiency might greatly help you in achieving top-notch optimization.

You may use any combination of bitmaps, graphic symbols, button symbols, and clips to create a sprite sheet. The symbols you have chosen will show up as separate graphics in the sprite sheet for each frame and bitmap. Any changes you have made to the symbol instance at the picture output will be retained when you export.

22. Avoid Re-Processing Data

Many applications use external servers to get data to obtain the necessary information for the app to work. Typically, this data is encountered in XML or JSON formats. It's crucial to make an effort to request and receive data using the same data structure on both ends. It might be costly to manipulate data in memory to make it suit your data structures.

For instance, you should definitely try to get a key/value pair dictionary if your application relies on being able to retrieve particular items by their keys.

You may save a lot of time and effort on your app by ensuring that the data is formatted correctly from the start, since this will help the data fit within the structure you have selected.

23. Choose the Right Data Format

There are a few ways you can do data transmissions from a web service into your app, but SON and XML are the most commonly used formats. All you have to do is choose the one that suits your app. This is how they differ:

JSON requires less data to send because it is easier to interpret and is typically smaller than XML. Additionally, JSON deserialization has already been incorporated into all iOS versions starting with iOS 5, and is user-friendly.

But, XML has an advantage: you can make use of XML data as you read it off the wire by implementing the SAX parsing method, which eliminates the need to wait for the complete data to arrive before processing it, unlike JSON. So, speedier and less memory use.

24. Speed up Launch Time

As I’ve mentioned at the beginning of the article, you need your app to work smoothly so that your users are satisfied — especially if it is the first time they are actually using your creation. Yeah, first impressions really do matter!

So, the most important thing you can do to guarantee a bump-free launch is to do as many asynchronous operations as you can, such as database queries, network requests, and data processing.

A tip: since big XIBs load on the main thread, try and avoid them, but keep in mind that storyboards don't have this issue, so make use of them when you can!

25. Choose Correct Data Storage Option

Last but not least, there are a few ways you can store and access massive data sets:

• NSUserDefaults for storage
• NSCoding to archive the file to a structured file in XML, JSON, or Plist format.
• Core Data
• Save to a local SQL database, such as SQLite.

Conclusion

These days optimization is a critical step in iOS app development. I have listed a few of the popular ways you can try to guarantee smooth and responsive performance of your app, as well as exceptional user experience, top market spot, and a much better ROI.