Full Stack Software Engineer at thinkingmachines | San Francisco

At Thinking Machines Lab, our mission is to enhance human capabilities through the development of collaborative general intelligence. We are dedicated to creating a future where everyone can utilize AI tailored to their specific needs and aspirations.Our team consists of accomplished scientists, engineers, and innovators responsible for some of the most popular AI applications, including ChatGPT and Character.ai, along with renowned open-weight models like Mistral and influential open-source projects such as PyTorch, OpenAI Gym, Fairseq, and Segment Anything.About the RoleWe are on the lookout for a passionate Software Engineer with a focus on security to ensure our products are secure by design while facilitating rapid and ambitious product development. You will collaborate closely with product and research teams to integrate security measures into the design and development processes, and create tools and automation to maintain system safety at scale.Note: This is an ongoing opportunity, and we encourage you to express your interest. While we receive numerous applications and there may not always be an immediate match for your skills, we encourage you to apply. We consistently review applications and will reach out as new roles become available. You may reapply if you gain additional experience, but please limit applications to once every six months. We also post specific roles for particular projects or teams, and you are welcome to apply for those as well.What You’ll DoCollaborate with product and research teams to integrate security into the development lifecycle: threat modeling, design reviews, and establishing secure defaults for new features.Design and implement security controls throughout our product stack (authentication, authorization, session management, input validation, etc.).Create and maintain security tooling and automation for engineers: secure frameworks and templates, CI/CD checks, dependency management, and vulnerability detection.Work alongside researchers to identify and address AI-specific product risks, such as model abuse, prompt injection, data leakage, or misuse of capabilities.Enhance observability and detection for security-related events: access anomalies, abuse patterns, and suspicious behavior in production.

At Thinking Machines Lab, our mission is to empower humanity by advancing collaborative general intelligence. We aspire to create a future where everyone can access the knowledge and tools necessary to harness AI for their individual needs and aspirations.Our team consists of scientists, engineers, and innovators who have developed some of the most renowned AI products, including ChatGPT and Character.ai, as well as open-weight models such as Mistral. We are also contributors to popular open-source initiatives like PyTorch, OpenAI Gym, Fairseq, and Segment Anything.About the RoleWe are seeking talented engineers to develop the libraries and tools that will expedite research at Thinking Machines. You will take charge of our internal infrastructure, which includes evaluation libraries, reinforcement learning training libraries, and experiment tracking platforms, all aimed at enhancing research velocity over time.This position emphasizes collaboration; you will engage directly with researchers to pinpoint bottlenecks and challenges. Your success will be measured by the trust researchers place in your systems and their enjoyment of using them.What You'll DoDesign, develop, and manage research infrastructure, including evaluation frameworks, RL training systems, experiment tracking platforms, visualization tools, and shared utilities.Create high-throughput, scalable pipelines for distributed evaluation, reward modeling, and multimodal assessments.Establish systems for reproducibility, traceability, and stringent quality control throughout research experiments and model training processes. Implement monitoring and observability.Collaborate closely with researchers to identify obstacles and unlock new capabilities. Manage research tools like a product manager, actively seeking feedback and tracking user adoption.Work alongside infrastructure, data, and product teams to ensure seamless integration of tools across the technical stack.

At Thinking Machines Lab, our vision is to enhance human potential by advancing collaborative general intelligence. We are dedicated to creating an inclusive future where everyone can harness AI's capabilities tailored to their unique aspirations.Our team comprises scientists, engineers, and innovators behind some of the most impactful AI solutions, including ChatGPT and Character.ai, as well as open-source projects like PyTorch and Segment Anything.About the RoleWe are seeking a talented Software Engineer to architect, develop, and maintain the GPU supercomputing infrastructure essential for large-scale AI training and inference. Your contributions will ensure high-performance, reliable, and cost-effective computing resources, enabling our users and researchers to achieve rapid advancements at scale.This is an "evergreen role," open for ongoing interest. We receive numerous applications, and while an immediate fit may not always be available, we encourage you to apply. We actively review applications and reach out when new opportunities arise. Reapplications are welcome after six months, and we also post specific roles for unique projects or teams.What You’ll DoAutomate and manage large GPU clusters, handling provisioning, imaging, and capacity strategy.Develop software that simplifies cluster management, providing a cohesive interface for training and inference tasks.Enhance scheduling and orchestration frameworks (Kubernetes, Slurm, or similar) for optimized resource allocation, preemption, and multi-tenancy management.Monitor and improve operational efficiency, focusing on speed, reliability, and error recovery mechanisms.Design robust storage solutions for datasets, checkpoints, and logs, ensuring clear data retention and lineage.Collaborate with researchers to facilitate large-scale experiments, offering guidance on parallelism and performance considerations.

At Thinking Machines Lab, we are committed to empowering humanity by advancing collaborative general intelligence. Our vision is to create a future where everyone has access to the knowledge and tools necessary to harness AI for their unique needs and aspirations.Our team comprises scientists, engineers, and builders who have developed some of the most utilized AI products, including ChatGPT and Character.ai, as well as open-weight models like Mistral. We also contribute to notable open-source projects such as PyTorch, OpenAI Gym, Fairseq, and Segment Anything.About the RoleWe are seeking a talented Infrastructure Research Engineer to enhance, scale, and fortify the systems supporting Tinker. This role will enable our internal teams and external clients to fine-tune models seamlessly, reliably, and cost-effectively. You will work at the intersection of large-scale training systems and product infrastructure, creating multi-tenant scheduling, storage, observability, and reliability features within a developer-friendly API.Your contributions will allow all Tinker users to concentrate on research and development without the burden of infrastructure concerns.Note: This is an evergreen position that we keep open for ongoing interest. We receive numerous applications, and there may not always be a role that aligns perfectly with your skills and experience. We encourage you to apply, as we continuously review applications and will reach out as new opportunities arise. You are welcome to reapply after gaining more experience, but please refrain from applying more than once every 6 months. We also post specific roles for unique project or team needs, and you are welcome to apply directly to those in addition to this evergreen listing.What You’ll DoDesign and implement distributed job orchestration, placement, preemption, and fair-share scheduling to enhance Tinker for multi-tenant workloads.Optimize GPU utilization, throughput, and reliability across clusters (including autoscaling, bin-packing, and quotas).Develop reusable frameworks and libraries to enhance Tinker’s transparency, reproducibility, and performance.Collaborate with researchers and developer experience engineers to transform fine-tuning challenges into product features.Publish and disseminate insights through internal documentation, open-source libraries, or technical reports to advance the field of scalable AI infrastructure.

At Thinking Machines Lab, our mission is to empower humanity by advancing collaborative general intelligence. We are dedicated to building a future where everyone can access the knowledge and tools necessary to harness AI for their unique needs and objectives.We are a team of scientists, engineers, and builders who have developed some of the most widely used AI products, including ChatGPT and Character.ai, and contributed to open-weight models like Mistral, along with popular open-source projects such as PyTorch, OpenAI Gym, Fairseq, and Segment Anything.About the RoleWe are seeking an Infrastructure Engineer to take charge of evolving the security infrastructure that supports our foundational models. In this pivotal role, you will collaborate across computing, storage, networking, and data platforms to ensure our systems remain secure, reliable, and scalable. You will design controls, architecture, and tooling that embed security into the platform's core functionalities. Working closely with research and product teams, you will enable them to operate swiftly while safeguarding our models, data, and environments.Note: This is an "evergreen role" that we maintain for ongoing interest. While we receive numerous applications, there may not always be an immediate position that perfectly matches your skills and experience. We encourage you to apply, as we continuously assess applications and reach out to candidates when new opportunities arise. Feel free to reapply if you gain more experience, but please refrain from applying more than once every six months. Additionally, we occasionally post openings for specific roles to meet project or team-specific needs, and in those cases, you are welcome to apply directly in conjunction with this evergreen role.What You’ll DoDesign security patterns for platforms and services, including network segmentation, service-to-service authentication, RBAC, and policy enforcement in Kubernetes and cloud environments.Oversee identity, access, and secrets management for users and services: workload and cross-cloud identity, least-privilege IAM, and secrets management.Create secure platforms for data ingestion, processing, and curation, encompassing classification, encryption, access controls, and safe sharing practices across teams.Develop threat models and review designs with researchers and engineers to facilitate safe and scalable feature launches.Automate security checks and implement guardrails: policy-as-code, secure infrastructure baselines, CI/CD validation, and tools that streamline secure operations.

About the RoleJoin Perplexity as a dynamic Software Engineer specializing in security, where you will play a pivotal role in developing and enhancing the software, automation, and systems that drive our security operations. This position focuses on engineering innovative security tools and AI-driven agents aimed at improving our detection and response capabilities, vulnerability management, and overall security posture across our products and infrastructure.ResponsibilitiesDesign, build, and maintain software and automation solutions that enhance our detection and response capabilities, including alert enrichment, triage workflows, and investigation tools.Implement and refine internal AI agents and security bots that facilitate monitoring, investigations, reporting, and other security operations tasks.Develop and manage systems and workflows that support our bug bounty and vulnerability disclosure program, covering intake, triage, prioritization, and remediation tracking.Collaborate with product and engineering teams to perform threat modeling on new features and systems, propose mitigations, and integrate security guardrails into designs and implementations.Contribute to secure-by-default libraries, services, and patterns that empower teams to build secure features effortlessly.Integrate security signals from cloud services, endpoints, SaaS, and applications into unified pipelines and data models that bolster detection and analysis.Automate processes to minimize manual effort in incident response, containment, and remediation.Work closely with security engineers and fellow software engineers to review designs and code, continuously enhancing our security tools and platforms.QualificationsA minimum of 4 years of experience as a software engineer, particularly in developing security-related tools, platforms, or automation, or in a security engineering role with a strong emphasis on software development.Proficiency in at least one major programming language (e.g., Python, Go, or TypeScript) with experience in building production services, command-line interfaces, or internal tools.Experience with integration of security-relevant systems such as logging pipelines, SIEMs, EDR, cloud APIs, or identity platforms.Hands-on experience in threat modeling, secure design, or conducting application security reviews for services or features.Experience in operating or contributing to bug bounty or vulnerability management programs is a plus.

Thinking Machines Lab aims to advance collaborative general intelligence, making AI accessible and adaptable for individuals and organizations. The team brings together scientists, engineers, and innovators behind well-known AI solutions, including ChatGPT, Character.ai, Mistral, and open-source projects like PyTorch, OpenAI Gym, Fairseq, and Segment Anything. Tinker, the lab’s fine-tuning API, helps researchers and developers customize AI models using their own data and algorithms. By handling the infrastructure, Tinker allows users to focus on training and deploying models that suit their needs. With a growing customer base and expanding features, the team is looking for a Software Engineer, Platform to support Tinker's continued development. Role overview This position centers on building and maintaining the core platform systems that power Tinker. The engineer will manage billing and usage metering, permissions and access control, organizational structures, data exports, audit logging, and the administrative tools that tie these systems together. Collaboration with product and legal teams is essential, as changes to features, pricing, and enterprise agreements will involve this role. What you will do Design the authorization layer for all products, including RBAC, API key scoping, organizational hierarchies, and permission boundaries. Oversee billing infrastructure, covering usage metering, plan management, payment processing, invoicing, and revenue recognition support. Develop and improve models for organizations and teams, such as seat management, SSO/SAML, workspace isolation, and invitation flows. Implement data export and deletion processes that align with enterprise standards and data residency requirements. Create audit logging systems to track user actions and decisions. This role is based in San Francisco.

Thinking Machines Lab brings together scientists, engineers, and innovators who have contributed to well-known AI products such as ChatGPT, Character.ai, and open-weight models like Mistral. The team’s open-source projects include PyTorch, OpenAI Gym, Fairseq, and Segment Anything. Their mission centers on advancing collaborative general intelligence and making AI tools accessible for a wide range of users and goals. The Tinker platform offers a fine-tuning API that lets researchers and developers tailor advanced AI models to their needs. By handling the underlying infrastructure, Tinker enables users to train open-weight models with custom data, algorithms, and objectives. As demand grows, the team is adding new features and supporting an expanding community. Role overview The Full Stack Software Engineer will play a key part in building and maintaining the products and services that Tinker users depend on. This position involves working closely with frontend, backend, and infrastructure teams to deliver the Tinker console, developer tools, and essential features. What you will do Develop and enhance Tinker’s APIs and backend services using Python and Rust, focusing on areas like job submission, orchestration, billing, and usage tracking. Design and launch user interfaces, including the Tinker console and upcoming developer tools, using React and TypeScript. Refine the developer experience by improving SDK usability, error messages, API design, and onboarding processes. Work to increase system reliability, observability, and security in production, and participate in on-call rotations. Create internal tools that help research and infrastructure teams work more efficiently. Location This role is based in San Francisco, California.

Join our dynamic team at Cloudflare as a Senior Software Engineer specializing in Security. In this role, you will work on cutting-edge security solutions that protect our customers' data and privacy. You will collaborate with cross-functional teams to design, develop, and implement robust security features while ensuring the scalability and performance of our systems. Your expertise in software engineering and security practices will be essential in driving innovation and leading projects to enhance our security posture.

Thinking Machines Lab brings together scientists, engineers, and innovators who have contributed to well-known AI products such as ChatGPT, Character.ai, and open-source frameworks like PyTorch, OpenAI Gym, Fairseq, and Segment Anything. The team's mission centers on advancing collaborative general intelligence, aiming to make AI accessible for people to address their own needs and ambitions. The Tinker platform offers a fine-tuning API that lets researchers and developers tailor advanced AI models to their specific requirements. Tinker provides the infrastructure, while users maintain flexibility to train open-weight models with their own data and algorithms. As Tinker grows its features and user base, the team is expanding to support the platform's evolution. Role overview This Full Stack Software Engineer role focuses on designing, building, and maintaining the products and services that Tinker users rely on. The work covers frontend, backend, and infrastructure, with an emphasis on the Tinker console, developer tools, and meeting the changing needs of the Tinker community. What you will do Develop and improve Tinker’s APIs and backend services using Python and Rust, including systems for job submission, orchestration, billing, and usage tracking. Build user-facing interfaces such as the Tinker console and future developer tools with React and TypeScript. Enhance the developer experience by refining SDK usability, error messages, API design, and onboarding workflows. Increase system reliability, observability, and security in Tinker’s production environment, and participate in on-call rotations. Create internal tools to support the research and infrastructure teams working on Tinker. This position is based in San Francisco.

Join Our Innovative TeamAs we approach the year 2026, we face what is being called the "infinite software crisis." At Sazabi, we are dedicated to solving this issue with our cutting-edge AI-native observability platform designed specifically for agile engineering teams.Our platform empowers teams to effortlessly inquire about their production systems using natural language, visualize real-time data, and swiftly identify root causes—10 times faster than traditional methods. No cumbersome instrumentation, no dashboard setups, and no alert configurations required—just straightforward solutions.We are proud to have the support of industry leaders from premier AI companies such as Vercel, Graphite, Daytona, Browserbase, LangChain, Mastra, Replit, and others.

About Cogent SecurityCogent Security is pioneering the future of cybersecurity through Applied AI, creating advanced AI agents designed to combat rapidly evolving cyber threats. Our AI Taskforce analyzes vast datasets to neutralize potential breaches before they impact our clients.Our commitment to innovation combines cutting-edge research with practical application, ensuring our solutions are at the forefront of technology. In addition to our product development, Cogent Research acts as our applied AI laboratory, supplying the expertise required to create highly effective security workflows.Since our launch from stealth mode, Cogent has seen remarkable growth, collaborating with Fortune 500 companies to secure some of the most intricate production environments globally.Backed by Greylock, our team consists of exceptional talents from leading universities such as Stanford, Berkeley, and Carnegie Mellon, as well as high-growth companies like Scale AI and Tesla, and cybersecurity experts from stalwarts like Wiz and DeepMind.

About Opal Security:At Opal Security, we are at the forefront of modern identity governance for the AI era. Our innovative access management solutions empower enterprises to accelerate their operations while ensuring robust security. Our mission is to provide clarity, control, and confidence in complex enterprise environments, enabling teams to manage access efficiently without hindering innovation.About the Role:Identity management is evolving rapidly, and as organizations deploy agents and create service accounts, traditional IAM stacks struggle to keep pace. At Opal, we are developing AI-driven security solutions that adapt to this dynamic landscape, with leading companies like Databricks and Figma relying on our expertise.In this role, you will design and implement customer solutions across our entire technology stack. Engaging directly with security and engineering teams at both Fortune 500 companies and innovative startups, you will gain insight into their unique challenges and architect systems that effectively address their needs. You will take ownership of the problem-solving process, allowing you to be creative, challenge existing assumptions, and develop groundbreaking solutions.Join a team that values collaboration and camaraderie. We prioritize thoughtful engineering over rushing through tasks, and you will work alongside individuals with diverse expertise, engaging in meaningful discussions and delivering work that you can take pride in.We are eager to welcome new team members who will contribute to and grow with our collaborative environment

About Us:At Notion, we empower individuals and teams to create beautiful, efficient tools tailored to their work. In an era where countless apps and tabs can overwhelm, Notion stands out by offering a unified space for collaboration. Our platform seamlessly integrates documentation, notes, projects, calendars, and emails—all enhanced with AI capabilities for streamlined workflows and insights. Our users, ranging from individuals to industry leaders like Toyota, Figma, and OpenAI, appreciate Notion's versatility, choosing us to save time and resources.We believe that in-person collaboration is vital to our culture. All team members are expected to work from our offices on designated Anchor Days—Mondays, Tuesdays, and Thursdays—though certain roles may require additional in-office days.About the Role:With millions of users and a continuously growing community, Notion is committed to providing a secure and reliable experience. As an Application Security Engineer, you will play a pivotal role in fortifying this trust while helping us innovate and expand our offerings. Your expertise will be essential in ensuring that our flexible and powerful application meets the security needs of thousands of businesses worldwide, safeguarding their data and that of their customers.We are seeking passionate security engineers dedicated to simplifying secure coding practices for developers. In this role, you will act as a consultant, advocate, and builder, focusing on preventing and addressing software vulnerabilities across Notion's product suite.What You'll Achieve:Contribute significantly to defining the direction and objectives of Notion’s Application Security team.Facilitate secure development by providing design guidance and developing solutions to eliminate vulnerabilities.Establish static and dynamic analysis rules to identify weaknesses within our codebase.Educate developers on security and privacy best practices to prevent vulnerabilities during development.Lead and participate in strategies to mitigate AppSec-related incidents.Develop and maintain tools that proactively prevent vulnerabilities or automate remediation.

About Cogent SecurityCogent Security is at the forefront of cybersecurity innovation, leveraging Applied AI to develop next-generation AI agents. In an era where cyber attacks evolve rapidly, our AI Taskforce analyzes vast amounts of enterprise data to proactively address vulnerabilities and prevent critical breaches.We combine pioneering research with practical execution, ensuring that our innovative solutions meet real-world challenges. Our Cogent Research division acts as our dedicated AI lab, driving the development of advanced security workflows.Since our emergence from stealth mode, we have rapidly grown, collaborating with Fortune 500 companies to secure complex production environments globally.Supported by Greylock, we have gathered a team of top talent from renowned institutions and leading organizations in the AI and cybersecurity sectors.About the RoleAs an Agent Engineer at Cogent Security, you will be pivotal in designing, building, and deploying critical AI agents tailored for complex client environments. Your role is highly cross-functional, involving direct collaboration with customers to understand their unique needs, adapting our platform accordingly, and iterating on scalable solutions to handle millions of real-world security events.You will manage projects from inception to deployment, including data onboarding and integrating feedback into our core agent platform. Your contributions will shape how AI agents detect threats, triage incidents, and automate security workflows for some of the most sophisticated organizations worldwide.This position is ideal for engineers who excel in dynamic environments, enjoy tackling complex technical challenges, and wish to see the tangible impact of their work.

About Cogent SecurityCogent Security is an innovative Applied AI Lab pioneering the future of AI agents in the realm of cybersecurity. In a world where cyber threats evolve at unprecedented speeds, our 'AI Taskforce' analyzes vast amounts of enterprise data to proactively address vulnerabilities and avert critical breaches.We remain at the forefront of technology by merging cutting-edge research with practical applications. Our dedicated Cogent Research team fuels our mission, ensuring we develop truly effective security workflows powered by AI.Since our inception, Cogent has rapidly grown, collaborating with Fortune 500 companies to safeguard the most intricate production environments globally.Supported by Greylock, our team comprises some of the brightest minds in applied AI, including experts from:Renowned universities such as Stanford, Berkeley, Penn, Duke, Carnegie Mellon, and Waterloo.High-growth unicorn companies like Scale AI, Databricks, Stripe, Tesla, and Coinbase.Leading cybersecurity specialists from Wiz, Abnormal AI, and Zscaler.Prestigious research institutions including DeepMind and SAIL.About the RoleAs we embark on building a suite of backend services and integrations with our design partners, we seek passionate and skilled Backend Engineers at both Senior and Staff levels, eager to thrive in the Applied AI domain.ResponsibilitiesDesign and implement critical backend subsystems and integration platformsComprehend business objectives and customer requirements to engineer backend subsystems that align with our technology strategies.Adapt systems to meet evolving needs of design partners and clients.Incorporate non-functional requirements such as compliance and security into system design.Establish scalable infrastructure foundationsPrepare for future growth in customer base, headcount, and data management by collaborating with your team to enhance infrastructure.

Join Decagon as a Security Engineer where you will play a crucial role in safeguarding our systems and data. You will collaborate with cross-functional teams to identify vulnerabilities, implement security measures, and ensure compliance with industry standards. This is an exciting opportunity to work in a dynamic environment and contribute to the security posture of our organization.

Juicebox is looking for a Security Engineer based in San Francisco. The main focus is to safeguard digital infrastructure and maintain the security of systems and data. Key responsibilities Develop and apply security measures throughout company systems Support compliance efforts with relevant industry security standards Location This role is based in San Francisco.

Join Our Team at MacroscopeAt Macroscope, we are dedicated to providing unparalleled insight into the software development landscape. Our mission is to empower leaders with the clarity they need and engineers with the time they deserve.We facilitate a deeper understanding of product and codebase evolution—identifying changes, tracking team contributions, and highlighting progress—all rooted in the ultimate truth: the code itself.Founded by seasoned entrepreneurs with a track record of launching and selling successful ventures, and seasoned executives from publicly traded tech companies, we are backed by premier venture capital firms and angel investors, including Lightspeed Venture Partners, Thrive Capital, Google Ventures, and Adverb.Your RoleWe are seeking a Senior Security Engineer to fortify and expand the security framework of Macroscope’s platform. In this pivotal role, you will design and implement robust security architectures, controls, and secure-by-default protocols across our distributed systems, infrastructure, and APIs that drive our core product.You will spearhead initiatives aimed at protecting customer data, reinforcing our production environment, and elevating security standards throughout our product offerings. Your expertise will ensure our systems adapt to customer demands while upholding enterprise-level security. Collaboration with the engineering team will be crucial as you establish best practices in identity and access management, cloud security, secure CI/CD, secrets management, vulnerability management, and production monitoring.As part of our compact team, you will work closely with founders, engineers, and designers to make architectural choices that will shape the future of our product and organization. This hands-on position is ideal for someone passionate about creating secure systems and empowering the team to innovate swiftly without compromising safety.Technology Stack: Typescript/React (frontend), Golang (backend), Temporal, Google Cloud (GCP), Postgres, Terraform, and custom-built AST “code walkers” in various languages (Golang, Typescript, Swift, Python, Rust).