Principal/Staff Engineer, Platform & Systems

ABOUT RETELL AIAt Retell AI, we are revolutionizing the call center experience using cutting-edge voice AI technology. In just 18 months since our inception, thousands of companies have leveraged our AI voice agents to streamline sales, support, and logistics operations that previously required extensive human teams. Supported by prominent investors such as Y Combinator and Alt Capital, we have grown from $5M to an impressive $36M ARR with a dedicated team of 20.Our ambitious vision for 2026 is to create a state-of-the-art customer experience platform where entire contact centers are driven by AI. Rather than relying on basic automation that necessitates constant human oversight, we are developing intelligent AI “workers” to function as frontline agents, QA analysts, and managers—constantly executing, monitoring, and enhancing customer interactions.As we rapidly expand, we seek passionate innovators eager to solve complex technical challenges, move swiftly, and make a meaningful impact at one of the fastest-growing voice AI startups. Join us in building the future!Ranked among the top 50 AI applications in the a16z list: https://tinyurl.com/5853dt2xRanked #4 on Brex's Fast-Growing Software Vendors of 2025: https://www.brex.com/journal/brex-benchmark-december-2025One of the top startups on the Leana I leaderboard: https://leanaileaderboard.com/THE ROLEWe are in search of a Principal/Staff Engineer to spearhead the technical direction of our core platform. This is an individual contributor role designed for someone who excels in uncertainty, acts swiftly, and elevates the standards of those around them.You will engage with various systems, infrastructure, and product surfaces while collaborating closely with engineering teams, product managers, and leadership to scale successful initiatives and innovate for the future.This role is not about merely addressing tickets; you will identify challenges, engineer solutions, and deliver impactful results.KEY RESPONSIBILITIESLead the design and evolution of our core platform and systems architecture.Oversee complex technical projects from inception to production.Make strategic technical decisions that optimize for speed, reliability, and scalability.Collaborate across teams to facilitate knowledge sharing and best practices.

At Fastly, we empower individuals to maintain meaningful connections with the things they cherish. Our cutting-edge edge cloud platform allows customers to deliver exceptional digital experiences with speed, security, and reliability by processing and securing applications as close to end-users as possible — right at the edge of the Internet. Our platform is engineered to harness the potential of the modern internet, enabling programmability and supporting agile software development. We proudly serve some of the world's most influential companies, including GitHub, Yelp, Paramount, and JetBlue.Join us in building a more trustworthy Internet.Posting Open Date: Reposted March 30, 2026Anticipated Posting Close Date*: April 20, 2026*This job posting may close earlier due to high applicant volume. Senior Principal Engineer, Platform EngineeringAs a member of Fastly’s Platform Engineering team, you will be instrumental in establishing the essential frameworks that enable engineers to deliver quickly, safely, and at scale. In the role of Senior Principal Engineer, you will guide the technical direction and spearhead cross-organizational initiatives aimed at enhancing our platform, developer experience, and operational excellence. Collaborating closely with fellow engineers, you will work to eliminate friction, standardize best practices, and create paved roads to expedite product delivery. This is a highly collaborative and hands-on position, representing the Platform Engineering organization and reporting directly to the Senior Director of Engineering.

At Forge, we recognize that our team is our most valuable asset. As pioneers in the private market technology sector, we aim to create a brighter future for all. This vision is embodied in our core values of boldness, accountability, and humility. We witness the impact of our vision daily, supporting the teams behind the most remarkable innovations of our era, from space exploration to artificial intelligence, and beyond.With our liquidity solutions, exclusive insights, custody offerings, and a dynamic marketplace, Forge strives to establish a leading-edge technology infrastructure that empowers a transparent, accessible, and seamless global private market for companies, their employees, and investors. Through Forge, employees can liquidate their private shares, employers can reward shareholders with pre-IPO liquidity, and both individual and institutional investors can engage with the growth of private unicorns.Forge's unique global marketplace meets the increasing demand from individual and institutional investors seeking exposure to private company stocks, creating a significant network effect.Our ability to provide these impactful financial solutions has sparked tremendous interest from investors, heightened customer demand, and a pressing need to expand our team to cater to the evolving requirements of more companies, teams, and innovators.The Role:As part of Forge's platform engineering team, you will join a group dedicated to innovation, developing scalable, secure infrastructure solutions that drive liquidity and growth in the private market. Our teams utilize a wide array of technologies to support our core platform, Metal, and we thrive on swift execution, delivering value, and adhering to our values of being bold, humble, and accountable.We are in search of a dedicated platform engineer with a minimum of 7 years of experience in delivering robust, scalable, and secure infrastructure solutions that are easy to maintain. The ideal candidate excels in collaborative environments and is driven by the desire to foster success through effective communication, crafting exceptional developer experiences, and making informed, data-driven decisions.To excel as a Staff Platform Engineer at Forge, you will leverage your expertise in infrastructure and software to deliver high-quality platforms both independently and through technical leadership of others. You will tackle advanced infrastructure projects – ranging from multi-cluster orchestration to SOC 2 compliance automation – while also being an engaged and collaborative team member.Location: This role requires in-office attendance 2-3 days a week in San Francisco, CA.

Join Cloudflare as a Principal Systems Engineer, Data, where you will lead innovative projects that enhance our data processing capabilities. You will work collaboratively with cross-functional teams to design, implement, and optimize systems that efficiently handle large-scale data. This role requires a deep understanding of systems engineering principles, strong analytical skills, and a passion for leveraging data to drive decisions. Your contributions will be pivotal in shaping the future of our data infrastructure.

Join Pinterest as a Principal Engineer for our Compute Platform, where you'll play a crucial role in driving the architecture and implementation of scalable systems that power our services. You will lead a team of talented engineers, guiding them in building innovative solutions that enhance our platform's performance and reliability.In this position, you will have the opportunity to collaborate with cross-functional teams, mentor junior engineers, and contribute to the development of best practices and high-quality code. If you are passionate about technology and eager to make an impact, we would love to hear from you!

Role overview Pinterest is seeking a Principal Engineer to join the Online Systems team, based in either San Francisco or Palo Alto. This position centers on designing and building scalable systems that serve millions of users. The focus is on enhancing user engagement and optimizing the performance of Pinterest's online platforms. What you will do Architect and develop large-scale applications built for high-traffic environments Collaborate with engineering, product, and design teams to deliver reliable solutions Lead technical decisions that influence the direction of Pinterest's online systems

Join Cloudflare as a Principal Systems Engineer specializing in Internet Protocol Communication (IPC). In this pivotal role, you will lead and innovate within our engineering team, playing a crucial part in enhancing our systems to support seamless communication over the internet. Your expertise will help shape our infrastructure and drive our mission to help build a better internet.

Role overview MidiHealth seeks a Staff Software Engineer for its Platform Engineering team. This hybrid role is based in the San Francisco Bay Area and centers on building software that supports the platform’s growth, performance, and usability. What you will do Design and develop software solutions that address platform engineering challenges Collaborate with experienced engineers to improve reliability and expand platform features Contribute to efforts that boost performance and create a smooth user experience Location This position requires a hybrid schedule, including on-site work in the SF Bay Area.

About Our TeamThe Platform Systems team at OpenAI is at the forefront of innovation, merging advanced AI technologies with large-scale distributed systems. We are tasked with creating the engineering and research infrastructure essential for training OpenAI's premier models on some of the most powerful, custom-built supercomputers globally.Our team is dedicated to developing the core software for model training, delving deep into the technological stack. This encompasses collective communication, compute efficiency, parallelism strategies, fault tolerance, failure detection, and observability. The systems we design are pivotal to enhancing OpenAI's research capabilities, facilitating reliable and efficient training at the leading edge of technology.We work in close partnership with researchers across the organization, continuously integrating insights from various OpenAI projects to advance our training platform.About the RoleAs a Software Engineer specializing in Platform Systems, you will architect and develop distributed systems that enhance visibility into large-scale training operations, ensuring their dependable operation at scale.Your responsibilities will include designing systems for failure detection, tracing, and observability that pinpoint slow or malfunctioning nodes, identify performance bottlenecks, and assist engineers in optimizing extensive distributed training tasks. This infrastructure is integral to the functionality of OpenAI's training stack and is continuously evolving to accommodate new use cases and increasingly intricate workloads.This position is central to our training infrastructure, merging systems engineering, performance analysis, and large-scale debugging.Key ResponsibilitiesDesign and develop distributed failure detection, tracing, and profiling systems tailored for large-scale AI training jobs.Create tools to identify slow, faulty, or errant nodes and deliver actionable insights into system behavior.Enhance observability, reliability, and performance across OpenAI's training platform.Troubleshoot and resolve issues within complex, high-throughput distributed systems.Collaborate effectively with systems, infrastructure, and research teams to advance platform capabilities.Adapt and expand failure detection and tracing systems to support new training paradigms and workloads.Ideal Candidate ProfilePossesses a deep passion for performance, stability, and observability in distributed systems.Demonstrates proficiency in systems engineering and performance analysis.Has experience in debugging high-throughput distributed systems.Exhibits strong collaboration skills with a track record of working with cross-functional teams.Shows adaptability and eagerness to embrace new technologies and methodologies.

Join Cloudflare as a Principal Systems Engineer and play a pivotal role in shaping the future of our cutting-edge technology solutions. In this hybrid position, you will leverage your extensive expertise to design and implement innovative systems that enhance our service offerings.

Airbnb connects millions of hosts and guests, offering stays and experiences in locations around the world. Since 2007, the company has helped over 2 billion guest arrivals discover new places and cultures. Role Overview The BizTech team at Airbnb is hiring a Staff Systems Engineer focused on Oracle EPM Planning systems. This role plays a key part in supporting the Finance team, acting as the technical architect and primary developer for the EPM environment. Main Responsibilities Design and develop scalable Oracle EPM solutions for Finance Budgeting and Forecasting. Build and refine financial forecasting models. Drive process improvements using AI technologies. Integrate EPM with data warehouse systems. Translate complex business requirements into technical solutions within Oracle EPM.

Role Overview The City and County of San Francisco's Department of Technology is hiring a Principal System Integration Engineer focused on enterprise systems with Python expertise. This position leads major integration projects that connect and enhance a wide range of internal systems. What You Will Do Design, develop, and implement integration solutions for enterprise systems Lead complex projects that require coordination across multiple platforms and teams Work closely with colleagues from different departments to solve technical challenges Improve system performance and reliability through thoughtful integration work Collaboration and Impact This role works at the intersection of technology and city operations. Projects often require input from diverse stakeholders and have a direct impact on how services run across the organization.

Join Lila Sciences as a Staff or Principal Engineer specializing in Technical Mitigations Research. This role offers an exciting opportunity to leverage your engineering expertise to develop innovative solutions in the field of technical mitigations.

Join Composio, where we are revolutionizing the infrastructure that empowers agents to seamlessly connect with the tools you utilize daily, including GitHub, Gmail, Notion, Salesforce, and more. Our dedicated team of engineers is tackling challenges from context management to search optimization, striving to create the most efficient bridge between your agents and their essential tools.Having secured a $25M Series A funding from Lightspeed, along with support from prominent angels such as Guillermo Rauch (CEO of Vercel), Dharmesh Shah (CTO of HubSpot), and Gokul Rajaram, we have experienced significant growth, tripling our ARR this year. Our customers range from fellow Y Combinator alumni to established companies like Wabi, Glean, and Zoom.Your ResponsibilitiesEnhance our platform primitives and APIs, including authentication, automatic refreshes, triggers, tool search, planning, and sandbox management.Oversee multiple runtimes for code execution across Lambdas and Firecracker.Optimize performance through tracing, CPU/heap profiling, database query enhancements, and workflow optimization.Collaborate closely with product engineering teams and customers to effectively manage their workloads and improve our product.Produce clear and comprehensive documentation.Essential QualificationsCore Platform Engineering Skills: Extensive experience in scaling backend distributed systems, maintaining reliable systems while delivering quickly, and managing multiple platform components simultaneously.AI Expertise: Familiarity with building and working with language models.Linux Proficiency: Comfortable working in a Linux environment.Effective Communication: Ability to write well-structured documentation and articulate complex ideas clearly.Interpersonal Skills: Cultivate trust and acknowledge areas for growth.Preferred QualificationsExperience with cloud infrastructure and serverless architecture.

Join Anthropic as a Staff Software Engineer on our Billing Platform team. In this critical role, you will design and implement robust billing solutions that scale with our growing user base. Collaborate with cross-functional teams to enhance our billing capabilities and ensure seamless processing of transactions. Your expertise will be vital in building systems that are not only efficient but also secure and user-friendly.

Join Discord, a platform cherished by over 200 million users monthly, where gaming is at the heart of our community. With more than 90% of our users engaging in games, they collectively spend 1.5 billion hours enjoying thousands of unique titles on Discord every month. Our commitment is to enhance the gaming experience by facilitating enjoyable interactions before, during, and after gameplay.At Discord, we empower individuals to connect within diverse communities, and our users trust us to safeguard their conversations. Our Platform Security Engineering team is dedicated to fortifying the systems that underpin Discord, ensuring that the "secure way" becomes the "easy way." We are seeking a Staff Software Engineer to drive this mission forward through your security expertise, software development skills, and operational excellence. In this technical leadership role, you will identify and pursue impactful opportunities to mitigate security risks across our Engineering teams. You will design and implement user-friendly "paved paths" for managing identities, deploying code, configuring cloud infrastructure, and operating services effectively.If you are a security engineer with a profound curiosity, keen on tackling technically and socially complex projects, and motivated to enhance security and privacy at Discord, we encourage you to explore this opportunity further!

Strava connects more than 180 million athletes across 185 countries, offering tools for tracking workouts, setting goals, and sharing progress. The platform supports a range of activities, including running, cycling, and swimming, and encourages community and personal growth. Role overview The Staff Engineer, Core Services Platform, will influence the technical direction of Strava’s social platform services. These services support key features such as the activity feed, photo and video sharing, experimentation, and notifications. This role involves guiding a small engineering team and leading modernization efforts across core services. Collaboration with product teams is central to ensuring the platform evolves to support both current and future needs. Work location This position follows a flexible hybrid schedule. In-office attendance is required three days per week at Strava’s San Francisco or Denver offices.

The Universal Directory Platform team at Okta develops and maintains the core systems that manage identity assets and their relationships for enterprise security. As a Staff Platform Engineer, this position focuses on building and supporting the backbone that enables identity management at scale. This role is based in San Francisco, California. The schedule is hybrid, with at least two days per week in the office. Key responsibilities Become familiar with the identity management codebase, development tools, and processes such as Jira, technical design documentation, code reviews, testing, and deployment workflows. Design and implement frameworks and tools for the Universal Directory Service platform. Develop distributed, scalable, high-performance, and fault-tolerant software components. Deliver high-quality bug fixes and resolve customer-reported issues promptly. Conduct thorough code reviews and contribute to automated testing initiatives. Collaborate with Product Development, QA, and Site Reliability Engineering teams to plan and execute development and deployment work. Requirements Proven experience building and deploying reliable, high-performance infrastructure and product code at scale in a cloud environment. At least 7 years of software development experience in Java, with strong knowledge of Hibernate and Spring Boot. 5 or more years developing services, internal tools, and frameworks. Minimum 3 years working with cloud infrastructure, service-oriented architecture, and microservices.

Quizlet, Inc. supports millions of learners each month by combining cognitive science with advanced machine learning. The platform serves two-thirds of U.S. high school students and half of college students, powering over 2 billion learning interactions monthly. Quizlet’s mission centers on making education more personal and effective for students, professionals, and lifelong learners. The AI & Data Platform team underpins Quizlet’s applied AI initiatives. This group develops and maintains the systems behind personalization, recommendations, the AI Coach, content generation, and emerging agentic experiences. The team oversees the full machine learning model lifecycle: data and feature engineering, training, evaluation, deployment, and inference. Reliability, speed, security, and observability guide their work. Their approach blends managed Google Cloud services, top vendor tools, open-source solutions, and custom internal abstractions to achieve efficient, reliable outcomes. Role overview The Senior Staff Engineer, AI Platform, is a senior individual contributor who defines the technical direction for Quizlet’s next generation of machine learning and large language model infrastructure. This hands-on role involves architecting core platform systems, steering build-versus-buy decisions, and collaborating with teams across Applied AI, Data Science, Product Engineering, and Infrastructure. The position sets standards for how models and LLM-driven systems are trained, evaluated, deployed, and governed at scale. This role is well suited to an engineer who excels at the senior-staff level in large organizations but values the autonomy and impact of a smaller, cloud-native setting. The technology stack includes Google Cloud, Kubernetes and GKE, distributed training, MLflow workflows, data and feature platforms, online and asynchronous inference, and the evaluation and observability tools needed to operate predictive ML and LLM systems at scale. Work location and schedule This is an onsite position based in San Francisco, CA. Team members are expected in the office at least three days a week: Monday, Wednesday, and Thursday, to foster collaboration.

Fastly is looking for a Staff Engineer to join the Edge Systems Efficiency team. This role centers on enhancing the performance, scalability, and efficiency of Fastly’s edge computing platforms. The work has a direct impact on the reliability and speed of Fastly’s global infrastructure. What you will do Optimize edge systems for greater efficiency and improved performance. Collaborate with cross-functional teams to identify and resolve technical challenges. Apply technical expertise to support new solutions and drive improvements at scale. Locations Denver, CO New York City, NY San Francisco, CA