JavaScriptCore Security Engineer

Cupertino Until 9/22/2026 4+ years exp First posted July 24, 2026 Last posted July 24, 2026
Job description

In this role, you have the opportunity to help secure the JavaScriptCore virtual machine. The JavaScriptCore team at Apple is looking for system programmers with experience in security, especially in programming languages, compilers, and virtual machines. You will be working to deliver a more secure web for all Apple products both proactively, by ensuring new features are implemented securely, and reactively, by responding to and addressing JavaScriptCore’s unique security challenges. The work is challenging, and the impact and reach are large. 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 is complex, with many subsystems: the compilation pipeline, the language runtime, the garbage collector and memory allocators, and the API for native apps. These subsystems run untrusted, third-party code, and all of them must do so in a memory safe way.

In this role, you will work across all areas of the engine, focusing on improving security and stability. You will drive new innovations in the security architecture of the codebase. You will fix security issues and respond to fuzzing. You will also ensure that security processes in JavaScriptCore are updated to current best practices and set the project up for a secure future.

Minimum Qualifications

BS in computer science or equivalent
Experience programming in modern C++
Excellent debugging, critical thinking, and communication skills
Experience developing privacy and security-sensitive software
Experience with compilers, parsers, and interpreters
Experience with assembly-level programming

Preferred Qualifications

Hands-on experience with VMs with just-in-time compilers (e.g. JavaScript engines and JVMs)
Experience with web browsers
Experience with memory allocators and garbage collectors
Experience with fuzzing, security architecture, and memory safety
Knowledge of JavaScript and WebAssembly

About this role

Summary

Secure and improve JavaScriptCore engine's security and stability.

Job title

JavaScriptCore Security Engineer

Experience level

null

Minimum experience

4+ years exp

Industry

software

Location requirements

Cupertino; remote not allowed

Salary

Not specified

Management role

No

Skills & keywords

Required skills

programming in modern C++debuggingsecurity-sensitive softwarecompilersparsersinterpretersassembly-level programming

Preferred skills

VMs with JIT compilersweb browsersmemory allocatorsgarbage collectorsfuzzingsecurity architecturememory safetyJavaScriptWebAssembly

Specializations

securityvirtual machinescompilersprogramming languagesmemory safety
Locations

Structured locations inferred from the posting.

Cupertino, CA, USA

On-site City