Perplexity is looking for a highly skilled Senior or Expert Systems Engineer to join our Search Core team. This role is critical to building next-generation search products and technologies. You will help drive key decisions around the architecture, design, and implementation of foundational components in our technical stack. Responsibilities • Design and build core search engine components, including indexing pipelines, retrieval algorithms, and ranking systems that operate at the scale of billions of pages • Develop streaming and batch data processing systems for search index construction in a high-load environment • Push the limits of hardware performance through low-level optimizations and systems-level tuning • Tackle challenges in multithreading, concurrency, and system-level optimization Qualifications • 3+ years of hands-on experience in systems programming (Rust, C++, C, or similar) • Ownership of full project lifecycle — you don't just write a fast inner loop, you care about how the system is built, deployed, operated, and scaled in production • Knowledge of Python or other scripting languages • Passion for writing clean, efficient, and scalable systems-level code • Strong knowledge of algorithms and data structures, and the ability to apply them effectively • Deep understanding of multithreading, including various approaches, challenges, and trade-offs • Experience building high-load, distributed, and hardware-adjacent services • Solid understanding of Linux internals (syscalls, networking stack, memory model, kernel tuning) • Familiarity with low-level optimization techniques (memory management, cache efficiency, SIMD, profiling) Preferred Qualifications • Experience developing core components of search engines, databases, or information retrieval systems • Understanding of search fundamentals: indexing, query parsing, ranking, and relevance • Experience with trading systems or other latency-sensitive real-time systems • Familiarity with cloud services, Kubernetes, and AWS infrastructure