Full Stack Software Engineer at gumloop | San Francisco

About the RoleWe are seeking a talented Senior Full-Stack Software Engineer to join our innovative team at Replo, located in the heart of San Francisco. In this pivotal role, you will focus on product engineering and contribute significantly to the development of our core product architecture while driving end-to-end feature development that impacts hundreds of thousands of users.As a senior engineer, your responsibilities will encompass core products such as our AI platform, inventory management, checkout systems, analytics, and integration with third-party providers. You will take ownership of these critical product areas from design to deployment, ensuring a streamlined process without layers of management obstructing your progress.Your role will evolve alongside Replo's growth, allowing you to set the technical direction, mentor budding engineers, and establish best practices across the team. There is potential for this role to transition into project and team management while continuing to contribute to code development and product excellence.

About the RoleWe are actively seeking an Engineering Manager dedicated to product engineering, who will initially engage as an individual contributor (IC) and write code. As Replo expands, your responsibilities will grow accordingly. You will determine the technical direction, mentor fellow engineers, and establish best practices within the team. This position will evolve into team management and collaboration with the co-founders, ensuring the successful delivery of outstanding products while remaining close to the coding process.Key ResponsibilitiesLead and develop a team of talented engineers, offering mentorship and guidance to foster their success and growth.Gain a deep understanding of customer requirements and challenges to prioritize tasks and deliver impactful solutions.Oversee project execution from planning and architecture to delivery, ensuring high quality and reliable timelines.Collaborate with high-profile teams and stakeholders to advance essential product and platform initiatives.Provide hands-on technical leadership, encompassing system architecture, design, incident response, and roadmap creation.Work closely with the founders daily to shape and implement Replo's long-term vision for our AI platform.Partner with the Chief of Staff to attract top engineering talent and devise hiring strategies as the team expands.Projects You'll Work OnArchitecting and implementing full-stack product features, including:Empowering merchants to sell anything, anywhere, including subscriptions, dropshipping, and digital products on a single platform.Creating agentic workflows for designing and building online shops for a diverse range of clients, from SaaS startups to established brands.Developing product and payment processing infrastructure for millions of users.Ingesting billions of events monthly using Kafka and ClickHouse to fuel real-time dashboards and automate marketing strategies.Managing our user onboarding and billing processes from start to finish.

Your Role at ReploAt Replo, we prioritize great service by focusing on outcomes rather than mere activity.We are actively seeking a dynamic Services Lead to spearhead a high-impact Services function while managing a portfolio of our most valuable clients from start to finish. In this role, you will transform the way Replo collaborates with ambitious brands, producing results that genuinely enhance their business, while also refining our product through direct customer insights.This position grants you significant ownership. You will oversee delivery processes, ensure execution excellence, interface directly with clients, and play a crucial role in defining how our service offerings, onboarding processes, and account management evolve over time. You will collaborate closely with our founders and leadership team, enjoying the autonomy to make impactful decisions and being accountable for the results.As you work alongside founders, marketers, and operators who are deeply invested in performance, quality, and return on investment (ROI), you will find a hands-on role in a fast-paced environment. This is an excellent opportunity for someone eager to contribute to something meaningful while fostering rapid growth.Your ResponsibilitiesClient Delivery & Customer OwnershipManage a portfolio of key Replo clients from onboarding through renewal and growth phases.Lead comprehensive onboarding processes, including technical setup, initial builds, and readiness for launch.Serve as the primary contact for strategy, execution, and problem resolution.Oversee the delivery of Replo-related service engagements, setting clear scopes, timelines, and expectations.Work directly with customers to create pages, flows, and experiments in Replo that yield measurable revenue increases.Handle multiple simultaneous engagements while maintaining high quality and reliability standards.Ensure all projects are aligned with clear business outcomes and demonstrate increased value from utilizing Replo.Facilitate renewals by ensuring clients understand and appreciate the ROI they are receiving.Expansion & GrowthIdentify opportunities for expansion (additional projects, upgraded tiers, services, or usage-based upsells) based on value delivered.Implement expansions seamlessly through effective delivery and trusted client relationships.Team & ExecutionCreate, manage, and maintain a high-performing team dedicated to delivering exceptional service.

About UsAt Replo, we've achieved rapid growth, expanding from 0 to over 5,000 customers in less than 18 months. Our vision is to create the ultimate platform for selling anything, starting with eCommerce where we are already a market leader, and we are poised to broaden our reach.Our company boasts strong revenue performance, rapid growth, and significant product momentum. However, we currently lack a robust customer success engine, which is where you come in.As a seed-stage company with Series A+ metrics, we are backed by notable investors including Y Combinator, Figma, and General Catalyst. Our team operates in-person 3 to 4 days a week from our headquarters in San Francisco.The RoleThis position marks Replo's first dedicated Customer Success hire.We serve thousands of active customersWe generate meaningful revenueOur customers are eager to succeed with ReploWe receive daily confirmation that Replo addresses customer pain points.Your primary responsibility will be to establish systems that enhance customer activation, provide ongoing value, and minimize churn, transforming customer success into a sustainable growth driver for the company.This is a unique opportunity to create impactful systems with full ownership and accountability.Key ResponsibilitiesInitially, your focus will be on customer activation, engagement, and retention.Your specific tasks will include:Engaging with customers through various channels (calls, onboarding sessions, QBRs, and escalations)Designing and implementing an effective customer onboarding experienceDefining success metrics for different customer segmentsDeveloping repeatable processes for:Customer activationOngoing engagementChurn prevention and risk detectionEstablishing and monitoring key performance indicators (activation rate, churn, retention, NPS, expansion)Identifying churn drivers and collaborating with Product, Sales, and Engineering teams to address themCreating scalable systems (tools, playbooks, workflows) to ensure effectiveness

About the RoleWe are looking for a passionate Full-Stack Software Engineer to join our dynamic team at Replo. Your primary focus will be on product engineering and delivering innovative features that enhance user experience.Key ResponsibilitiesAs a Full-Stack Engineer, you will architect and implement product features using Typescript, React, and Node. Your work will involve:Developing workflows that design, build, and optimize online shops.Creating and maintaining product and payment processing infrastructure.Launching analytics infrastructure on Clickhouse and Kafka that handles billions of events monthly.Taking ownership of the user onboarding process from start to finish.Ideal Candidate ProfileWilling to work in-office 3-4 days a week in San Francisco.Proficient in Typescript, React, and Node.Utilizes tools like Cursor, Windsurf, or GPT for enhanced productivity.Experienced in building products from the ground up with real users and generating revenue.Capable of working independently without the need for product/design input.Has a strong bias for action and is committed to shipping products quickly.Possesses a product and customer-centric mindset.Experienced with deployment and maintenance challenges and has well-formed opinions on product development.Values clean, maintainable code and thorough documentation.Comfortable navigating ambiguity and defining software architecture patterns to address customer pain points.Bonus QualificationsHolds a degree in Computer Science or a related STEM field.Has entrepreneurial experience or has previously started a company.Enjoys participating in hackathons.Has experience working in early-stage startups (Series A or earlier).Has not invested excessive time preparing for interviews on platforms like Leetcode.Possesses an eye for design, with experience in product design tools like Figma.

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.

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.

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!

Join our dynamic team at gumloop as a Senior Full Stack Engineer, where you will play a pivotal role in shaping our technology landscape.Take ownership of end-to-end feature development: design, implement, test, deploy, and maintain your creations in production.Collaborate closely with users to swiftly transform feedback into actionable improvements, achieving results within hours, not days.Develop and manage scalable front-end and back-end solutions that maintain speed and reliability as user traffic increases.Contribute to the growth of the team by reviewing pull requests, providing context, and mentoring junior engineers.

At CreatorIQ, we are dedicated to revolutionizing creator-led growth, empowering over 1,300 global brands and agencies to thrive.Our mission is to humanize businesses while amplifying the impact of individuals. Guided by our core values—intentionality, excellence, collective journey, and humanity—we have been recognized as one of the best workplaces by various programs, including BuiltIn LA and NY. Our growth story includes being named one of the Fastest-Growing Companies in North America by Deloitte Technology Fast 500™ for four consecutive years, and being highlighted as a leader in IDC MarketScape: Worldwide Influencer Marketing Platforms for Large Enterprises in 2025, among others. Our flexible work model fosters collaboration and innovation, accommodating diverse working styles.Join us in our exciting journey. Become a vital part of our dynamic team and help transform the industry!Senior Full Stack Engineer, Creator RecruitWe are looking for a talented Senior Full Stack Engineer to enhance our Creator Tools team. Your contributions will significantly improve user experiences and help us develop scalable solutions for our expanding platform.The ideal candidate will possess a strong background in frontend frameworks, solid backend development skills, and a collaborative spirit suited for a fast-paced environment. You should be ready to take ownership of features, contribute to architectural decisions, and maintain high coding standards.The Creator Tools team is responsible for developing all user-facing features on our platform, directly impacting the lives and livelihoods of creators who utilize our tools to earn and sustain their businesses.From payment processing and social authentication to e-commerce solutions and campaign workflows, we enable the full creator experience. Every feature you develop and enhancement you implement is integral to delivering a seamless, intuitive platform that empowers creators to grow and earn with confidence.This role allows you to make an immediate and meaningful difference in the lives of creators who rely on our platform to pursue their passions.

Join Plaud as a Senior Full Stack Engineer and contribute to innovative software solutions that make a difference. This role offers the opportunity to work in a dynamic environment where you will collaborate with cross-functional teams to design, develop, and implement web applications.

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.

ABOUT SPHERESphere is revolutionizing trade compliance with cutting-edge AI technology. Our innovative system, TRAM, autonomously analyzes and interprets global trade laws, ensuring reliable compliance determinations across various jurisdictions. We manage the full compliance lifecycle—from calculation and registration to filing and remittance—with millisecond latency and zero downtime.At Sphere, we are proud to be backed by prominent investors such as a16z and Y Combinator, and we've achieved over 30% month-over-month growth. Our impressive client roster includes emerging leaders like ElevenLabs, Replit, Deel, and Runway. We operate with a small, dedicated team in our San Francisco headquarters, where every member has ownership over significant domains of our platform.THE ROLEWe are seeking experienced Senior Full Stack Engineers to spearhead the development of new product lines, including input tax, withholding tax, e-invoicing, and tariffs. Your contributions will be pivotal in scaling our operations and directly influencing our annual recurring revenue (ARR).WHAT YOU'LL DOWithin weeks:Deliver critical features that clients rely on daily, such as filing infrastructure.Take ownership of a feature and drive measurable outcomes.Collaborate with customers like Eleven Labs, Lovable, and Deel to enhance key components of our platform, aiming to improve filing generation and submission speeds.Within months:Lead the end-to-end development of new product lines, furthering our AI-driven compliance platform.Mentor junior engineers and foster a collaborative team environment.

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.

Why Choose Alex?At Alex, one of the most promising startups emerging from our Y Combinator batch, we are making significant strides in the hiring landscape. We have secured strong funding, are generating revenue, and have ample runway to fuel our growth.Our innovative AI-driven recruitment tool revolutionizes the job interview process, enabling companies to obtain critical hiring insights more swiftly and effectively than ever. Our clients are enthusiastic about our product, and we are just beginning our journey.Who We Are?We are a team of individuals who:Thrive on tackling complex engineering challengesAdapt quickly and are committed to achieving resultsDedicate ourselves to hard workAct with urgencyValue in-person collaboration in our San Francisco office, five days a weekTechnologies We UtilizeWe prefer candidates with experience in:JavaScript (Typescript, React, Node, Next)PythonCloud and DevOps tools (Azure, Kubernetes, Docker)System ArchitectureYour ResponsibilitiesAt Alex, we operate similarly to a marketplace, providing unique interview experiences for candidates and a robust data analysis platform for employers. As a hands-on engineer, you will develop both consumer-facing applications and enterprise-grade software, with ample opportunities for professional growth. Potential consumer software challenges include:How can we reduce average interviewer response latency to 200ms?How can we refine our models to minimize hallucinations and help Alex pass the Turing test?How will our system architecture evolve as we scale to accommodate thousands of users concurrently?You will also address enterprise-related software challenges such as:How do we integrate with our clients' internal hiring systems?What is the optimal way to visually present interview results swiftly?How can Alex facilitate end-to-end coordination of the hiring process?And a myriad of feature requests awaiting your expertise!

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.

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.