JavaScript Virtual Machine Compiler Engineer

Cupertino Until 9/22/2026 First posted July 24, 2026 Last posted July 24, 2026
Job description

In this role, you have the opportunity to push the state of the art of JavaScript and WebAssembly performance. The JavaScriptCore team at Apple is looking for system programmers with compiler (especially just-in-time) and virtual machine experience. You will be working to deliver a faster and more secure web for all Apple products by improving JavaScriptCore’s already world-class JIT compilers, runtime systems, and the garbage collector. The work is challenging, and the impact is worldwide. Join us.

Description

The JavaScriptCore team in WebKit is responsible for the JavaScriptCore engine, and our mission is to make JavaScript and WebAssembly execution both fast and secure. JavaScriptCore engineers work on all aspects of the engine: the compilation pipeline, the language runtime, the garbage collector, and the API for native apps. The compilation pipeline consists of the parser, the bytecode frontend, profile-guided type profiling, and multiple optimizing compiler backend that turn JS and Wasm programs into efficient ARM and x86 machine code.

In this role, you will work across all areas of the engine, improving the performance, security, and stability of the engine, as well as compatibility with other browsers. You will also help guide the evolution of the JavaScript and WebAssembly languages via public standards. You will drive new innovations, add new optimizations, tune performance, implement language features, in addition to diagnosing and fixing existing problems.

Minimum Qualifications

BS in computer science or equivalent
Experience programming in modern C++
Excellent debugging, critical thinking, and communication skills
Experience with compilers, parsers, and interpreters
Experience with assembly-level programming
Experience with performance analysis
Experience with memory allocators and garbage collectors

Preferred Qualifications

Hands-on experience with VMs with just-in-time compilers (e.g. JavaScript engines and JVMs)
Experience with web browsers
Knowledge of JavaScript and WebAssembly

About this role

Summary

Improve JavaScriptCore engine performance, security, and stability across all areas.

Job title

JavaScript Virtual Machine Compiler Engineer

Experience level

none

Industry

software

Location requirements

located in Cupertino, no remote work specified

Salary

Not specified

Management role

No

Skills & keywords

Required skills

modern C++debuggingcompilersparsersassemby-level programmingperformance analysismemory allocatorsgarbage collectors

Preferred skills

JIT compilersweb browsersJavaScriptWebAssembly

Specializations

compilervirtual machineJITJavaScriptWebAssembly
Locations

Structured locations inferred from the posting.

Cupertino, CA, USA

On-site City