Software Engineer - X Developer Platform

SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars. SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next. RESPONSIBILITIES: Design, build, and implement a large-scale distributed system that powers one of the world's largest supercomputing clusters. Dive into the low-level stack to profile, debug, and optimize performance across diverse systems, including GPUs, Linux kernel, networking, and filesystems, to achieve peak efficiency. Collaborate on hardware, software, and algorithm co-design to push the boundaries of AI training. Maintain and innovate on our codebase to ensure scalability and reliability. Develop tools to enhance team productivity and streamline workflows. BASIC QUALIFICATIONS: Systems programming experience in C, C++, or Rust Computer systems fundamentals with a grasp of how computers execute code from transistors to high-level applications. Hands-on expertise with Kubernetes (K8s), including cluster architecture, pod lifecycle, networking (CNI), storage (CSI), service mesh, and production-grade operations PREFERRED SKILLS AND EXPERIENCE: Collaborate in a fast-paced, open environment to design and foundational systems. Strong debugging skills across the full stack — from kernel and OS up through container orchestration layers Deep knowledge of operating systems intern

SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars. SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next. About the Role: We are building the high-performance inference platform that serves Grok to millions of users every day with lightning speed and perfect reliability. As a Member of Technical Staff - Inference, you will design and optimize large-scale model serving systems end-to-end. You will own everything from distributed infrastructure (global KV cache, continuous batching, load balancing, auto-scaling) to deep low-level optimizations (GPU kernels, quantization, speculative decoding, tail latency). This is a high-impact role where your work directly determines how fast and reliably users interact with Grok at massive scale Responsibilities: Architect and implement scalable distributed infrastructure for model serving (load balancing, auto-scaling, batch scheduling, global KV cache). Optimize latency and throughput of model inference under real production workloads. Build reliable, high-concurrency serving systems that serve billions of users with 100% uptime, 0% error rate, and excellent tail latency. Benchmark, fine-tune, and accelerate inference engines (including low-level GPU kernel work and code generation). Develop custom tools to trace, replay, and fix issues acr

SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars. SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next. ABOUT THE ROLE: The Observability team builds and operates the core infrastructure that enables engineers to monitor, debug, and optimize the performance and reliability of their systems. We handle telemetry at massive scale — billions of time series and petabytes of logs — with strict performance and availability requirements. You will be part of the small, high-impact team responsible for building and maintaining SpaceXSI's observability platform. You’ll own critical systems that power metrics, logs, tracing, and alerting enabling engineering teams to operate services at scale, identify issues before they impact users, and drive systemic reliability improvements. RESPONSIBILITIES: Design and implement scalable observability infrastructure for metrics, logging, and tracing. Build high-performance telemetry pipelines that handle massive ingestion volumes. Develop APIs, query engines, and UIs that allow engineers to get real-time insights into their services. Define and enforce best practices for instrumentation, alerting, and reliability across the company. Partner with infrastructure and product teams to deeply integrate observability into our internal platforms. Own the reliab

SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars. SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next. ABOUT THE ROLE: We are building one of the world’s largest AI supercomputers from the ground up. As part of the Compute Infrastructure team, you will own both the raw GPU supercomputer and the platform layer that runs on top of it. You will work across the full stack — from low-level GPU kernel optimizations and Linux kernel internals to massive-scale orchestration and virtualization — to make training and inference at SpaceXSI as fast, reliable, and scalable as possible. This is a broad, high-impact role that combines hardcore supercompute and compute infrastructure work. Your contributions will directly accelerate Grok’s training speed and overall AI progress. RESPONSIBILITIES : Design, build, and optimize massive GPU clusters for extreme-scale training and inference workloads Develop and tune low-level CUDA kernels (GeMM, Attention, etc.), using CUTLASS, Tensor Cores, and Nsight for maximum performance Profile, debug, and eliminate bottlenecks across GPU memory hierarchy, networking fabric, filesystems, and multi-GPU operation Collaborate closely with AI research teams to deliver production-grade performance and scalability PREFERRED SKILLS AND EXPERIENCE: Deep low-level syst

SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars. SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next. ABOUT THE ROLE: We are seeking a skilled and innovative Application Security Engineer to join 𝕏 Money. In this role, you will protect the security and integrity of our payments and financial products throughout the software development lifecycle, with a particular focus on code security, CI/CD pipelines, and systems that move and hold customer funds. Experience securing fintech, payments, digital wallet, ledger, or similar high-value platforms, where fraud, abuse, and unauthorized transfers are a constant concern, is strongly preferred. RESPONSIBILITIES: Conduct in-depth code reviews and static analysis to identify and mitigate security vulnerabilities in financial applications Design and implement secure coding guidelines and best practices for development teams Collaborate closely with development teams to integrate security practices throughout the CI/CD pipeline Perform threat modeling and risk assessments for payments, wallets, ledgers, and related product surfaces, and develop mitigation strategies for fraud, abuse, and unauthorized movement of funds or credits Manage vulnerability tracking and remediation efforts, providing guidance to development teams Manage the

SpaceX was founded under the belief that a future where humanity is out exploring the stars is fundamentally more exciting than one where we are not. Today, SpaceX is actively developing the technologies to make this possible, with the ultimate goal of making life multiplanetary and expanding consciousness to the stars. SpaceXSI is building Super Intelligence to help humanity understand the universe. Our teams are building the full Super Intelligence stack: from our Colossus supercomputers, to Grok models, to our suite of applications, including Grok Bot, Grok Build, Grok Imagine, Grok Voice, and X. We're creating a powerful flywheel where more compute trains better models, better models power more useful products, and what we learn from people using those products shapes what we build next. ABOUT THE ROLE: As an engineer for Consumer Subscriptions (X Premium & SuperGrok), you will own the entire billing and monetization infrastructure powering one of SpaceXSI's fastest-growing revenue organizations. You will build and lead the dedicated engineering team responsible for subscriptions, promotions, global payments, and personalized user experiences at massive scale. This high-impact engineering role offers the opportunity to directly drive significant revenue growth while architecting systems that serve hundreds of millions of users worldwide and shape the future of premium AI and social products. RESPONSIBILITIES: Own the complete billing infrastructure for consumer subscriptions end-to-end, ensuring world-class reliability, security, and scalability. Design and build sophisticated promotional offer infrastructure and internal tools to supercharge the revenue organization. Develop comprehensive communications systems enabling intelligent push, email, and in-app messaging that drive engagement and conversions. Implement market-specific billing methods and compliance solutions to accelerate global expansion. Architect compelling product bundles across the X ecosyst