hardScenarioDesignSeniorStaff
How do you resolve severe performance bottlenecks in a complex React Native application caused by heavy bridge traffic, and how do you evaluate a migration to the JavaScript Interface (JSI)?
Assess the candidate's understanding of the React Native architecture, bridge performance limitations, profiling techniques, and modern solutions like JSI and the New Architecture. Use this MOBILE answer to show the decision, trade-off, and evidence rather than a memorised definition. It also connects cross platform to the point an interviewer is testing.
3 min readUpdated 2026-08-15
Answer
Short answer
React Native bridge bottlenecks come from serializing too much data between JavaScript and native code. Profile the bridge traffic, batch or eliminate noisy calls, move hot paths native-side, and migrate performance-critical modules to JSI or the New Architecture deliberately.
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Likely follow-ups
- How do you prioritise which native modules to migrate to JSI first when you cannot rewrite everything at once?
- What regressions would you watch for immediately after enabling Fabric on a codebase with many third-party UI libraries?
- How do you debug a memory leak introduced by a cyclic reference between a JS object and a C++ host object?
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