High memory usage for `Text` component on iOS
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Description
Description
When working on memory optimisation of a complex RN app, I found that Text components on iOS can consume relatively large amounts of memory. When I've checked that with Xcode Instruments, it seems that each RCTParagraphTextView is accompanied by a backing CALayer which consumes memory proportional to its rendered size, more precisely width x height x 4 bytes (RGBA channels).
While individual Text instances are small, complex UI, esp. using stacked screens & virtualized lists can add up to quite large number (tens of MB), especially if the app uses large font sizes in such lists.
For example, each of the following Text components consumes about 112-140 KB of memory, due to the backing raster.
This can be observed using Allocations Xcode Instrument by marking memory before and after adding text views.
I've created a small app for easily measuring various components' memory usage: https://github.com/mdjastrzebski/rn-memory-footprint
Note:
- on Android, this issue does not seem to happen, as all Text have similar size, regardless of used font size
- on iOS, when using native
UILabel, these are much smaller, and do not haveCALayersattached
Steps to reproduce
- Download the reproducer app
yarn install&yarn ios:releaseORyarn android:release- Run the app on a simulator or a device
- Attach Allocation Xcode Instrument, mark generation A
- Pick "Text (Large Font)" from the component dropdown
- Press "Create Views"
- Wait a couple of seconds, mark generation B in instruments
- Compare memory usage. You should see a lot of
RCTParagraphTextView (CALayer)entries, each taking 120-140 KBs.
React Native Version
0.82.1
Affected Platforms
Runtime - iOS
Output of npx @react-native-community/cli info
System:
OS: macOS 26.1
CPU: (11) arm64 Apple M3 Pro
Memory: 102.75 MB / 36.00 GB
Shell:
version: "5.9"
path: /bin/zsh
Binaries:
Node:
version: 22.17.1
path: /Users/mdj/.nvm/versions/node/v22.17.1/bin/node
Yarn:
version: 4.12.0
path: /Users/mdj/.nvm/versions/node/v22.17.1/bin/yarn
npm:
version: 10.9.2
path: /Users/mdj/.nvm/versions/node/v22.17.1/bin/npm
Watchman:
version: 2025.07.28.00
path: /opt/homebrew/bin/watchman
Managers:
CocoaPods:
version: 1.16.2
path: /Users/mdj/.rbenv/shims/pod
SDKs:
iOS SDK:
Platforms:
- DriverKit 25.0
- iOS 26.0
- macOS 26.0
- tvOS 26.0
- visionOS 26.0
- watchOS 26.0
Android SDK:
API Levels:
- "35"
- "36"
Build Tools:
- 35.0.0
- 36.0.0
System Images:
- android-35 | Google Play ARM 64 v8a
- android-36 | Google Play ARM 64 v8a
Android NDK: Not Found
IDEs:
Android Studio: 2025.2 AI-252.25557.131.2521.14432022
Xcode:
version: 26.0.1/17A400
path: /usr/bin/xcodebuild
Languages:
Java:
version: 17.0.16
path: /usr/bin/javac
Ruby:
version: 3.4.5
path: /Users/mdj/.rbenv/shims/ruby
npmPackages:
"@react-native-community/cli":
installed: 20.0.0
wanted: 20.0.0
react:
installed: 19.1.1
wanted: 19.1.1
react-native:
installed: 0.82.1
wanted: 0.82.1
react-native-macos: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: true
newArchEnabled: true
iOS:
hermesEnabled: true
newArchEnabled: true
Stacktrace or Logs
n/a
MANDATORY Reproducer
https://github.com/mdjastrzebski/rn-memory-footprint
Screenshots and Videos
Added above
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Reproduce the issue with the linked rn-memory-footprint app using the “Text (Large Font)” component and Xcode Allocations Instrument. Start by tracing the RCTParagraphTextView and its backing CALayer, then compare the observed iOS behavior with native UILabel and Android; done means the excessive per-view memory usage is addressed without changing Text behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- ios, react-native
- Domain
- mobile, performance
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100