Full-Stack Software Engineer at Alexai | San Francisco

About AnthropicAt Anthropic, we are dedicated to building AI systems that are reliable, interpretable, and steerable. Our goal is to ensure that AI is safe and advantageous for our users and society at large. We are a rapidly expanding team of devoted researchers, engineers, policy experts, and business leaders collaborating to develop beneficial AI systems.Role Overview:Join our Product Engineering team at Anthropic! We are seeking talented engineers proficient in full-stack development to help design, build, and deploy advanced capabilities across our current and future product offerings—from prototypes to production. Collaborate with product leaders, designers, and researchers to explore new model capabilities and redefine user experiences in the realm of Large Language Models (LLMs). You will be expected to possess a solid product intuition, enhance technical quality across the stack (including performance, accessibility, reliability, and developer experience), and scale your efforts to millions of users globally, all while being genuinely enthusiastic about the potential of AI.We are currently hiring for multiple teams. Team assignments will occur post-interview based on your interests and experience in conjunction with the needs of our organization. This flexible approach enables us to align skilled engineers with backend product initiatives where they can have the most substantial impact and growth opportunities.Your Responsibilities:Developer Experience: You will create products and tools—including consoles, SDKs, documentation, and observability features—that empower developers to confidently utilize Claude in their most critical applications. Our mission is to meet developers in their workflow and elevate their capabilities with our models and API. This involves fostering trust through excellent platform fundamentals, inspiring developers to enhance their utilization of Claude's features, and facilitating agentic development for both human and AI developers. Collaborate closely with teams across the platform organization to transform Claude's latest capabilities into tangible experiences that developers can easily adopt—from initial prompt to production agent.Beneficial Deployments: We are looking for experienced software engineers to join our Beneficial Deployments Engineering team. Your role will involve bringing Claude to communities that stand to benefit most from AI technology, including nonprofits, educational institutions, healthcare entities, life sciences researchers, and economic mobility initiatives worldwide.Enterprise Applications/End Users: You will...

About AnthropicAt Anthropic, we are dedicated to developing AI systems that are not only reliable but also interpretable and steerable. Our goal is to ensure that AI serves the best interests of our users and society as a whole. Our rapidly expanding team consists of passionate researchers, engineers, policy experts, and business leaders, all collaborating to create beneficial AI systems.About the RoleWe are seeking skilled engineers with a strong foundation in full-stack development to join our Product Engineering organization. In this role, you will serve as a technical leader, taking comprehensive ownership of the user experience across various platforms, including Claude.ai, the Anthropic API, enterprise solutions, Claude Code, and mission-driven applications. You will work in partnership with engineering managers, product leaders, designers, and researchers to explore new model capabilities and redefine user experiences in the realm of large language models (LLMs). Your product-oriented mindset and commitment to technical excellence will be essential as you scale our services to millions of users globally, while fostering a genuine passion for the potential of AI.We have multiple teams actively hiring, and team placement will occur post-interview, taking into account your interests and experience alongside organizational needs. This flexible approach allows us to align talented engineers with backend product initiatives where they can make the most significant impact and achieve maximum growth.

Join Condor Software as a Full-Stack Platform EngineerAt Condor, we are revolutionizing the financial infrastructure that supports clinical development. With billions invested annually in discovering and developing new therapies, we strive to connect clinical operations and finance into a cohesive system. By integrating real-time financial intelligence, we empower R&D and finance leaders with the tools they need to make informed, high-stakes decisions.We are an AI-driven, pharma-native infrastructure provider, scaling industry standards in collaboration with top-tier partners. Our platform facilitates prediction, control, and execution in the most complex R&D environments worldwide.The Importance of Your RoleHaving established ourselves as a trusted partner for enterprise teams, we are now focused on the challenging task of scaling our platform to meet increasing demands. As a rapidly growing company, backed by prominent investors like Felicis and 645 Ventures, this is a unique opportunity to contribute to the foundational infrastructure that will redefine how therapies reach patients.Your ResponsibilitiesAs a Full-Stack Platform Engineer, you will be pivotal in building and scaling the core platform that supports the financial intelligence infrastructure relied upon by leading biopharma companies. This role encompasses critical engineering tasks at the intersection of backend systems, cloud infrastructure, and intelligent automation, with a strong emphasis on reliability and scalability.Your primary focus will be on backend architecture, where you'll design and implement services that drive complex financial and operational workflows. You'll be instrumental in shaping data flow, workflow orchestration, and enabling emerging AI-driven capabilities. This role goes beyond simple integration; you'll be crafting robust primitives that support other teams as our product and customer base expand.Working as a core member of a cross-functional product team, you will closely collaborate with product managers, designers, quality engineers, and data specialists to transition features from concept to production. While backend expertise is crucial, you will also engage across the stack to ensure the platform's capabilities are effectively leveraged.

About HappyRobotHappyRobot is pioneering the AI-native operating system for the real economy—an innovative platform that seamlessly integrates intelligence with actionable outcomes. By harnessing real-time insights, specialized AI agents, and a coordinating intelligence, we empower enterprises to manage intricate, mission-critical operations with genuine autonomy.Our AI OS continuously accumulates knowledge, optimizes processes at every level, and adapts over time. We're initially focusing on supply chain and large-scale industrial operations, where resilience, speed, and ongoing enhancement are paramount—liberating humans to concentrate on strategic thinking, creativity, and other high-value pursuits.Discover more about our vision in our Manifesto. HappyRobot has successfully secured $62M in funding to date, including a recent $44M Series B round in September 2025. Our esteemed investors include Y Combinator (YC), Andreessen Horowitz (a16z), and Base10, who share our commitment to transforming enterprise operations. We are channeling this investment into assembling a world-class team—individuals with unwavering determination, exceptional problem-solving abilities, and a passion for pushing boundaries in a dynamic, high-pressure environment. If this resonates with you, we invite you to join us at HappyRobot.About The RoleAt HappyRobot, Full Stack Engineers take charge of significant components of the product and infrastructure from start to finish.We are seeking creators who thrive in uncertain environments, have a profound appreciation for their craft, and desire authentic ownership over their creations.

About Tacit Tacit is an early-stage deep tech startup based in San Francisco, focused on hardware that changes how people interact with computers. Backed by General Catalyst, Khosla Ventures, and Greylock Partners, the team brings experience from Stanford, BrainGate, Oculus, and Tesla. The company is committed to solving complex engineering problems to deliver new products that push the boundaries of human-computer interaction. Role Overview The Full-Stack Software Engineer will help turn ambitious ideas into real products, working across Tacit's software stack. This role involves taking features from initial concept through to deployment and shaping user experiences that support the company’s mission. What You Will Do Develop the internal product stack to improve workflows and prototypes across devices and companion clients. Build and expand internal applications for demos and data collection, supporting idea testing and user experience validation. Prototype new features for human-computer interaction, iterate with test users, and refine until the experience feels seamless. Design and run product experiments, including A/B tests and feedback loops, to quickly gather insights and guide product direction. Streamline data collection and participant experiences, including setup flows, session reliability, metadata capture, monitoring, and labeling. Develop demo features that showcase real-time sensing and inference in engaging, reliable ways. Find and implement integrations that improve team workflows and efficiency. Create and improve automated testing and release systems, such as CI/CD pipelines, smoke tests, and regression checks, to support frequent updates. Work closely with machine learning, hardware, and industrial design teams to define requirements, deliver results, troubleshoot, optimize, and ensure reliability. Qualifications Strong skills in Python (FastAPI, Pydantic; experience with pandas or numpy) and modern TypeScript/React. Experience building production backends (APIs, data models, reliability, observability) and delivering features for end users. History of shipping multiple products from start to finish.

Join Anthropic as a UI Software Engineer and become a vital part of our innovative team dedicated to creating intuitive and engaging consumer products. In this role, you will leverage your expertise in user interface development to design and implement user-friendly applications that enhance our clients’ interactions with AI technologies.

At Siftstack, we are revolutionizing the development, testing, and operation of modern machines. Our innovative platform empowers engineers with real-time observability over high-frequency telemetry, effectively eliminating bottlenecks and facilitating faster, more dependable development.Founded by a team of experts from SpaceX, Google, and Palantir, Siftstack was inspired by our experience with pioneering projects like Dragon, Falcon, Starlink, and Starship. Our mission-critical infrastructure is designed for precision and scalability, meeting the highest demands of reliability in engineering.As an early-stage engineer at Siftstack, you will not only write code, but you will also play a pivotal role in defining our architecture, shaping our product, and cultivating a culture focused on addressing real engineering challenges. If you thrive on tackling complex technical problems and want to build foundational systems that support intricate machines, we'd love to hear from you.

About AnthropicAt Anthropic, we are dedicated to developing AI systems that are reliable, interpretable, and steerable. Our goal is to ensure that AI serves as a safe and beneficial tool for users and society alike. Our rapidly expanding team comprises passionate researchers, engineers, policy experts, and business leaders who collaborate to create beneficial AI technologies.About the TeamThe Security Engineering team at Anthropic is committed to safeguarding our AI systems and upholding user trust. We establish the authentication architecture for our training infrastructure, design cryptographic systems to protect model weights and training data, and oversee a developer security program that influences how our engineers create and deploy software.This team operates across various interconnected domains: identity and secrets management, developer security and supply chain, infrastructure security, and secure frameworks. You will take ownership of one or two of these domains while also contributing to others, with your area of focus influenced by your expertise and the team's objectives. This role primarily involves greenfield projects, allowing you to help shape the architectural landscape.About the Role:Design, scope, and implement complex security systems from start to finish, ensuring their maintenance in production while navigating ambiguous technical challenges with minimal supervision.Identify systematic risks through comprehensive threat modeling and risk assessment, subsequently developing the necessary controls and infrastructure to mitigate these risks.Mentor engineers within the security team and the wider engineering organization, participate in the hiring process, and foster a robust security culture at Anthropic.Empower other teams to develop their own security solutions by offering design pattern guidance and expanding security ownership beyond the security team.Developer Security and Supply ChainEnhance our developer security program by integrating security practices into the software development lifecycle and developer workflows.Fortify CI/CD pipelines against supply chain threats through isolated build environments, signed attestations, dependency verification, and automated policy enforcement.Identity and Secrets ManagementDesign systems that safeguard sensitive assets, including model weights, customer data, and training datasets.Establish and maintain credential issuance, rotation, and workload authentication across our multi-cloud environments.

About StackAIStackAI is a revolutionary no-code AI workflow platform that enables businesses to construct, implement, and expand AI-driven workflows without requiring extensive machine learning expertise. With a growing user base and increasing enterprise adoption, our goal is to democratize access to large language models (LLMs), empowering every business operator—beyond just developers. Supported by Y Combinator and top-tier investors, we are laying the groundwork for the AI-driven future of work.The RoleAs a Senior Full Stack Engineer, you will be instrumental in defining the product and technical architecture at StackAI. Your responsibilities will span the entire technology stack, from crafting scalable backend systems to creating stunning and user-friendly frontend interfaces, and incorporating advanced AI models into our platform. This role offers significant impact, as you will work closely with the founding team, take charge of essential product features, and shape the engineering culture of a rapidly evolving startup.We seek exceptional 10X engineers—innovative builders who can consistently deliver results in a dynamic environment, remain inquisitive, and excel in diverse roles.ResponsibilitiesIn this role, you will:Build and own the entire platform, from backend services and APIs to frontend interfaces.Create robust, scalable backend systems utilizing Python and FastAPI (or similar), with optimized databases (SQL/NoSQL).Design and maintain high-quality user interfaces using React, Next.js, TypeScript, and Tailwind CSS, ensuring polished, intuitive, and responsive user experiences.Integrate new AI models and features into our products for seamless performance and enhanced value.Manage StackAI’s landing and product pages to establish benchmarks for clarity, design, and quality.Collaborate across the stack to connect backend services with frontend applications seamlessly.Engage with design, product, and customers to refine product direction and prioritize user needs.Stay at the forefront of full-stack technologies, promoting best practices and innovative solutions.Assist with customer support as needed; every team member contributes to user satisfaction.

About Numeral:Numeral is revolutionizing the tax landscape for digital businesses, helping them navigate the complexities of regulations across 47 states and over 50 countries. Our mission is to lift this burden so that teams can concentrate on their primary objectives.As the largest and fastest-growing AI-driven tax solution, Numeral was established in 2023 and has successfully raised over $57 million from notable investors such as Benchmark, Mayfield, and Y-Combinator. We proudly serve more than 2,500 paying customers and have consistently tripled our revenue year over year since our inception.While our main hiring hubs are in San Francisco and New York, we do offer remote opportunities based on specific circumstances.About the Role:We are in search of a foundational Full-Stack Engineer who thrives in dynamic environments, enjoys constructing intricate distributed systems, and is eager to establish core architecture within a rapidly expanding early-stage startup. You will spearhead the design and implementation of APIs, services, and infrastructure that form the backbone of our platform. Additionally, you will collaborate with leadership to drive engineering strategy, product execution, and cultural development.Your Responsibilities:Design and develop scalable and secure backend services and APIs from the ground up.Make architectural choices that prioritize speed, data integrity, and long-term sustainability.Work closely with product, design, and data teams to create efficient systems that enhance crucial customer workflows.Take ownership of infrastructure, observability, and performance for the services you create.Contribute to the establishment of engineering best practices, code quality, and a robust backend culture.What You Bring:Over 7 years of experience in developing backend systems in high-growth settings.Proficiency in backend technologies such as Node.js, PostgreSQL, Redis, and cloud services (AWS preferred).Experience in designing resilient APIs and distributed systems at scale.A strong product sensibility with the ability to balance performance, flexibility, and speed.A startup mindset: comfortable with ambiguity and eager for swift growth.Intensity & Ownership: This role goes beyond a standard 9-5 — we are rapidly scaling and face exciting opportunities ahead.Customer Obsession: A genuine commitment to enhancing user experience and resolving their challenges.

Join us as we create a revolutionary gamified developer platform that enables thousands of developers to engage in thrilling software engineering challenges that explore the limits of LLMs.As a Full Stack Software Engineer, you will integrate into a dynamic, enthusiastic team focused on tackling complex technical issues, crafting captivating gamification experiences, and establishing robust systems that facilitate collaboration among developers worldwide.Key ResponsibilitiesDevelop and sustain comprehensive features across both frontend and backend systems.Design scalable, high-performance backend services and user-friendly, responsive frontend interfaces to enable real-time coding competitions and engaging user experiences.Work closely with product managers, designers, and engineers throughout the stack to swiftly deliver impactful features.Lead technical discussions, influence architectural decisions, and identify areas for enhancement across the entire technology stack.Establish engineering best practices that include code quality, testing protocols, observability, and thorough documentation.QualificationsMinimum of 3 years of experience developing scalable, high-performance full stack applications in production settings.Proficient in creating frontends with React, TypeScript, and Tailwind CSS.Experience in designing secure and efficient APIs and backend services using Go.Familiar with cloud infrastructure and services (AWS) and Docker.Possess a proactive approach, comfortable with rapid iteration based on user feedback.Preferred QualificationsExperience with Infrastructure as Code (IaaC) using Terraform and CI/CD pipelines.Background in designing secure code execution environments and implementing sandboxing techniques.Interest in or experience with gamification, competitive programming, or developer-centric platforms.

Join our dynamic team at gumloop as a Full Stack Software Engineer, where you will play a pivotal role in shaping our product and impact.In this role, you will:Develop and launch comprehensive features from design through to deployment and management in a production environment.Rapidly iterate based on user feedback, ensuring swift enhancements and same-day releases.Collaborate closely with our founders daily to maintain clear priorities and eliminate obstacles.Create sleek user interfaces alongside robust backend systems that can handle increasing traffic.

Full Stack Software Engineer (Various Levels)Join our client, a pioneering organization dedicated to developing the most advanced non-invasive technology for interfacing with the human brain. They are focused on creating an innovative ultrasound-based platform that can stimulate and image brain activity with unmatched resolution and depth, unlocking new avenues in neurological treatment, research, and human health.By integrating state-of-the-art hardware, real-time software systems, and applied neuroscience into a cohesive product stack, they aim to deliver scalable solutions that enhance lives on a global scale. We are currently seeking a Full Stack Software Engineer to contribute significantly to the development of software systems that bridge complex hardware, real-time data, and user interaction.

Superhuman embraces a vibrant hybrid working model that perfectly balances focused individual work with collaborative in-person interactions to cultivate trust, innovation, and a robust team culture.About SuperhumanSuperhuman, now empowered by Grammarly, is an innovative AI productivity platform dedicated to unlocking the extraordinary potential within individuals. Our suite of applications seamlessly integrates AI into daily workflows, connecting with over 1 million applications and websites. Our offerings include Grammarly's writing enhancement tools, Coda's collaborative workspaces, Mail's inbox management solutions, and Go, our proactive AI assistant that intuitively understands context to provide timely assistance. Since our inception in 2009, Superhuman has empowered over 40 million users, 50,000 organizations, and 3,000 educational institutions worldwide, enabling them to streamline their tasks and concentrate on what truly matters. Discover more at superhuman.com and explore our core values here.The OpportunityTo fuel our ambitious growth, we are seeking talented Full-Stack Software Engineers to join our engineering teams. As a Full-Stack Engineer at Superhuman, you will be instrumental in developing key components of our product offerings, infrastructure, and features that enhance the writing capabilities of our 40 million users. This role offers a unique opportunity to engage in both Front-End and Back-End development, contributing to highly visible and impactful projects.Our engineers and researchers enjoy the freedom to innovate and drive breakthroughs that directly influence our product roadmap. As we scale our interfaces, algorithms, and infrastructure, the complexity of our technical challenges continues to grow. You can learn more about our technical endeavors on our technical blog.Superhuman is experiencing rapid growth, creating opportunities to join dynamic teams, learn from seasoned professionals, and build innovative products from the ground up. Within our expanding engineering organization, you will find ample room for ownership and a direct impact on user experience.As a Full-Stack Engineer, your responsibilities will include:Rapidly building and deploying code, with the opportunity to deliver significant features within your first few months.Developing and maintaining high-performance Back-End services and creating engaging user interfaces on the Front-End.

About ChalkChalk is at the forefront of developing a cutting-edge data platform that revolutionizes machine learning applications. We are committed to dismantling the traditional barriers of complexity, latency, and scalability that have limited ML capabilities. By merging high-performance Rust technology with user-friendly tools, we empower developers and organizations alike. Our platform is trusted by leading companies to combat fraudulent credit card transactions, validate identities, and optimize clean energy utilization. Recently, we secured a $50 million Series A funding round, spearheaded by Felicis.About the RoleWe are actively seeking passionate Full Stack Software Engineers to join our dynamic team. This is a unique opportunity to contribute significantly as an early employee within a rapidly growing startup. You will have the autonomy to tackle complex engineering challenges while taking full ownership of your work.Our ideal candidates are versatile engineers who excel at addressing business challenges across all layers of the software stack. At Chalk, we prioritize building robust data processing systems that perform efficiently at scale, all while focusing on an exceptional developer experience.We require engineers capable of crafting outstanding user experiences across both CLI and web interfaces, alongside a strong understanding of a codebase enriched with concepts from compilers, query planners, and distributed systems.Our team works in the office five days a week, with flexibility for unavoidable conflicts. Please note, this is not a hybrid position.What You Will DoCollaborate directly with Chalk’s co-founders to bring our first iteration to production.Develop applications using TypeScript, Python, Go, and React.Contribute to a codebase that incorporates advanced ideas from various fields.

As the Communications Lead at Anthropic, you will play a pivotal role in shaping and sharing our narrative with external stakeholders. You will oversee our communication strategies, ensuring that our messaging aligns with our mission and values. The ideal candidate will possess a strong background in communications, with a proven ability to engage diverse audiences through impactful storytelling and strategic outreach. Join us in our mission to build safe AI systems and contribute to positive societal outcomes.

Formic is looking for a Full Stack Software Engineer with a focus on robotics to join the team in San Francisco or Oakland, CA. This position involves building software that advances robotic capabilities, with responsibilities across both front-end and back-end development. Role overview This role centers on creating and improving software that supports robotics projects. Collaboration with cross-functional teams is a key aspect, ensuring that applications are scalable and effective for real-world use. What you will do Develop and maintain software for robotics systems, working on both client and server sides Partner with engineers and other teams to design and implement new features Contribute to solutions that improve how robotics function and interact Location This position is based in San Francisco or Oakland, CA.

Join Binti as a Senior Full Stack Software Engineer and play a crucial role in developing innovative software solutions that enhance our mission to streamline the adoption process. You will be responsible for designing, developing, and maintaining our web applications, ensuring optimal performance and user experience.In this position, you will collaborate with cross-functional teams, participate in all phases of the software development lifecycle, and mentor junior developers. If you are passionate about building scalable applications and are eager to solve complex problems, we want to hear from you!

About AnonAnon is revolutionizing the way enterprises can deploy authenticated AI agents to enhance their crucial data workflows.We are tackling one of the most significant challenges in enterprise automation: extracting and transforming data that is hindered by authentication barriers. Our innovative platform empowers AI agents to securely connect with any web-based system, extract unstructured data, and present it through state-of-the-art APIs.Since our inception in 2023, we have partnered with industry leaders to convert lengthy manual processes into streamlined automated workflows that can be completed in mere minutes. With $14M raised from notable investors such as Union Square Ventures, Forerunner Ventures, Okta Ventures, and Abstract Ventures, we are on a path of rapid growth.Our vision is clear: we believe every business system should be accessible to AI agents. If you are passionate about developing infrastructure that will support the next wave of AI applications, we invite you to join our dynamic team of 12 in San Francisco.www.anon.com/careersAbout the RoleAs a Full Stack Engineer at Anon, you will play a pivotal role in creating both the user interfaces and the underlying infrastructure that drive our authenticated AI agents for enterprise workflows. Your responsibilities will include developing React-based dashboards for agent monitoring, crafting embeddable authentication components, and constructing the APIs and data pipelines that convert unstructured web data into accurate and reliable outputs. This is a chance to take ownership of features from inception to deployment while engaging at the intersection of AI and enterprise software.Key ResponsibilitiesCore Platform DevelopmentCreate robust AI agents capable of navigating web interfaces, managing dynamic content, and extracting data from systems lacking APIs.Develop front-end interfaces for agent creation, monitoring dashboards, and real-time execution visualization.Take full ownership of features from database to UI, encompassing API design and user experience.Design embeddable JavaScript components and authentication modals to facilitate customer integrations.Build and maintain scalable APIs, data pipelines, and authentication workflows across various platforms.Develop integrations with third-party services and ensure comprehensive test suites are maintained.Collaborate & LearnPartner with senior engineers to gain insights into system architecture and best practices.Engage in code reviews and share knowledge with your peers, fostering a culture of continuous improvement.