Previously, we explored how memory is measured and what tools are available for inspecting usage in iOS apps. Now, let’s shift our focus to reducing memory consumption using a set of practical techniques and development best practices. But first let’s discuss different approaches to treat this problem.
Initial Source of a Problem
Every spike in memory has a cause, and memory optimization is no exception. Sometimes it’s a 3rd-party library — Lottie is a classic example, especially if you export animations from After Effects and it ends up loading every frame as a raw bitmap. Other times, it’s your own code — maybe a local class that creates and deletes heavy objects without much control.
There are usually two ways teams deal with memory growth:
– Reactive approach. You ship first, and worry only if memory usage starts ballooning. This is common for small or indie teams with tight deadlines, simple flows, or low data volume. If it scrolls smooth, no one’s profiling UIScrollView. The downside? If memory becomes a problem later, untangling the logic might be painful. I’ve been there — one lazily loaded animation spiked memory to 1GB just because it can.
– Proactive (defensive) coding. This is about thinking ahead — using defer to clean up resources, preferring lighter assets, considering NSCache or smarter containers, swapping animation frameworks, or hardcoding assets if needed. There’s no silver bullet, but the earlier you start managing memory consciously, the less tech debt you’ll face later. And honestly, nothing feels better than seeing your app stay under 50MB of memory on a cold start.
Let’s discuss how to be informed about it and some main places of optimizations.
How to Respond to Low-Memory Warning?
When your app starts getting close to the system’s memory limit, iOS gives you a heads-up — that’s when the memory gauge hits yellow in Xcode. You’ll get a memory warning, and it can come in a few different ways:
applicationDidReceiveMemoryWarning(_:) gets called on your app delegate, but it’s slowly getting deprecated.
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