JSI, C++ & Runtime Boundaries
Native modules designed around direct JSI access, reduced bridge pressure, predictable memory behavior, and C++ execution for latency-sensitive work.
Low-level React Native Infrastructure
Alex Shumihin
React Native + C++ + JSI performance engineer.
I build bridge-free native modules, binary data pipelines, runtime integrations, and performance-critical mobile infrastructure where JavaScript is not allowed to be the bottleneck.
JSI / TurboModules
C++ native core
AVFoundation
Runtime internals
Zero-copy buffers
JSI
C++
TurboModules
AVFoundation
Runtime internals
Swift
Kotlin
Skia
Reanimated
SQLite
CI/CD
Deep Expertise
Low-level React Native infrastructure, not just app screens.
JSI bindings and C++ cores for hot paths
Binary buffers, hashing, IDs, base64, and native schedulers
Runtime-aware design around threads, memory, and bridge overhead
Binary Data & Media Pipelines
ArrayBuffer transport, image buffers, hashing, base64, native schedulers, SQLite/WatermelonDB flows, and media integrations such as AVFoundation.
Rendering & Product Delivery
Smooth interactions with Reanimated, Gesture Handler, Skia, plus native iOS/Android integrations, releases, CI/CD, and production ownership.
Performance Research
Benchmarks that expose where React Native actually spends time.
Representative benchmark themes from native-module research and open-source work.
JS bridge vs JSI call path
bridge-freeArray vs ArrayBuffer transport
zero-copyWork moved off JS thread
up to 10x
JS thread
JSI boundary
C++ / native thread
Keep parsing, hashing, scheduling, media, and buffer operations outside UI-critical JavaScript work.
Published Research
Authored engineering articles on React Native internals.
Published engineering research on React Native internals, JSI boundaries, data layout, and native performance.
How to Make Pure JSI Code Faster in React Native
A deep dive into JSI performance: HostFunction vs HostObject, NativeState, stack allocation, and reducing JS ↔ C++ crossings, with benchmarks showing where the real gains come from.
Read on Margelo BlogMaking JSI Faster with more Efficient Data Structures
How data shape, API design, and string building impact JSI performance, with real benchmarks and up to 30x speedups.
Read on Margelo BlogArchitecture Case Studies
Open-source libraries as proof of low-level execution.
361
react-native-auto-skeleton
Automatically generates skeleton screens from existing UI layout without manual configuration.
86
rn-fade-wrapper
Fade gradient wrapper for React Native scroll views and overlays.
24
react-native-columnar
Zero-copy data transport from JSI C++ to JavaScript via columnar ArrayBuffer layout.
20
react-native-xxhash
High-performance xxHash generation for React Native using optimized C++ and JSI bindings.
16
react-native-turbo-base64
Fast base64 encode/decode for React Native with optimized C++ and JSI bindings.
15
react-native-ulid-jsi
Ultra-fast ULID generation for React Native using JSI and native execution.
More libraries
Native modules and utilities beyond the pinned set.
Stack
Native-grade React Native infrastructure toolkit.
React Native
JSI
C++
Swift
Kotlin
AVFoundation
Objective-C
Java
Reanimated
Gesture Handler
Skia
SQLite
WatermelonDB
GraphQL
WebSockets
CI/CD
About
About my work
My work sits at the boundary between React Native and native runtimes: JSI, C++, Swift/Kotlin, AVFoundation, binary data, rendering, memory, and the runtime internals that decide whether a mobile product feels instant or heavy.