Senior Full Stack Software Engineer at Retell AI | San Francisco

About Retell AIAt Retell AI, we are pioneering the future of call centers through innovative voice AI technology. Our cutting-edge solutions are transforming how companies engage with customers.In just 18 months since our inception, we've empowered thousands of businesses with our AI voice agents that efficiently manage sales, support, and logistics calls, significantly reducing the need for large teams of human agents. Supported by industry-leading investors including Y Combinator and Alt Capital, we've grown our annual recurring revenue from $5M to an impressive $36M while expanding our team from 5 to 20 talented individuals since 2025.Our ambitious vision for 2026 is to develop a state-of-the-art customer experience platform where entire contact centers are driven by AI. Unlike basic automation requiring constant human oversight, we’re engineering intelligent AI “workers” capable of serving as frontline agents, quality assurance analysts, and managerial roles, all while optimizing customer interactions continuously.We are rapidly expanding and seeking driven builders who thrive on solving complex technical challenges, act decisively, and wish to make a tangible impact in one of the fastest-growing voice AI startups.Join us in shaping the future!Recognized as a top 50 AI application in the a16z list: https://tinyurl.com/5853dt2xRanked #4 in Brex's Fast-Growing Software Vendors of 2025: https://www.brex.com/journal/brex-benchmark-december-2025Featured among the top startups on: https://leanaileaderboard.com/

Responsibilities:Develop Our Product. Take ownership of software features that enhance our AI platform, empowering private market investors to analyze deals swiftly and accurately. This role requires you to actively engage in coding and delivering essential platform components from the ground up.Ensure Quality and Excellence. Establish and maintain coding standards, architectural guidelines, and review procedures; mentor fellow engineers. Co-cultivate a culture centered on practical, reliable, and test-driven development that swiftly meets business requirements.Scale for Growth. Assist in monitoring and scaling the architecture of our platform and its infrastructure.Collaborate Across Functions. Engage closely with product, security, and go-to-market teams to translate our strategic roadmap into actionable features and deliverables.

The Trade Desk is a leading global technology company dedicated to fostering a better, more open internet for everyone through principled, intelligent advertising. With the capability to handle over 1 trillion queries daily, our platform operates at an unparalleled scale. We pride ourselves on our award-winning culture, built on the foundations of trust, ownership, empathy, and collaboration. We appreciate the unique experiences and perspectives that every individual brings to The Trade Desk, and we are committed to creating inclusive spaces where everyone can express their authentic selves at work. If you are passionate about solving complex problems at scale and are eager to join a dynamic, globally-connected team where your contributions will significantly impact the media ecosystem, we invite you to explore why Fortune magazine consistently ranks The Trade Desk among the top small to medium-sized workplaces worldwide. As a Senior Software Engineer, you will have end-to-end ownership, allowing you to engage in various facets of designing, building, and delivering data-centric products for our stakeholders. At The Trade Desk, we focus on constructing the back-end infrastructure of our platform with an unwavering commitment to quality at scale. Whether developing components for our client-facing applications, crafting internal custom solutions for our teams, or building model pipelines for bidding optimizations, we ensure that the infrastructure, development processes, and tools empower us to execute efficiently. Our systems operate continuously, serving global traffic, and we collaborate in a highly cooperative environment while leveraging a diverse array of technologies. Our back-end developers tackle algorithmic, optimization, and scalability challenges across all our initiatives.

fractional-ai is looking for a Senior or Staff Software Engineer to join the San Francisco office. This position centers on building advanced AI solutions with a team that values both technical depth and collaboration. Role overview This role focuses on designing and developing AI-driven systems. The work involves solving technical challenges and contributing to projects that push the boundaries of what AI can achieve. Collaboration with other engineers and stakeholders is a key part of daily responsibilities. Who will thrive Experienced engineers with a strong background in software development Those who enjoy working on complex technical problems Individuals who value teamwork and open communication Location This position is based in the San Francisco office.

Join the Revolution at Retell AIRetell AI is pioneering the future of call centers through innovative voice AI, driven by first principles thinking.In just 18 months since our inception, we have empowered thousands of businesses with our AI voice agents, transforming how sales, support, and logistics calls are managed—previously requiring extensive human teams. Supported by prestigious investors such as Y Combinator and Alt Capital, we've rapidly scaled from $5M ARR to an impressive $36M ARR with a compact yet dynamic team of 20.Our ambition for 2026 is to create a revolutionary customer experience platform, where entire contact centers are powered by AI. Moving beyond basic automation, we aim to develop intelligent AI “workers” that serve as frontline agents, QA analysts, and managers, continuously enhancing customer interactions without the need for constant human oversight.As we expand, we are seeking passionate engineers who are eager to solve challenging technical problems, act swiftly, and make a significant impact in one of the fastest-growing voice AI startups. Let’s shape the future together.

Role overview retell-ai seeks a Senior Software Engineer in the San Francisco Bay Area to focus on Go-To-Market (GTM) projects. This engineer will help shape how new products are created and introduced to customers, directly influencing the company’s approach to launching and scaling offerings. What you will do Collaborate with teams across the organization to translate business needs into software that advances GTM objectives. Develop and improve products to ensure they fit seamlessly into the market. Uphold high standards for code quality and system performance as products grow and change. Collaboration This position works closely with product, business, and engineering partners to deliver solutions that address both technical and market demands.

Supported by key investors from Silicon Valley, Peregrine Technologies empowers public safety organizations, state and local governments, federal agencies, and private-sector institutions to address societal challenges with remarkable speed and precision. Our AI-driven platform transforms disconnected data into actionable insights—instantly delivering vital information that enables quicker, more informed decisions, resulting in improved outcomes across various touchpoints. Currently, Peregrine serves hundreds of clients in over 30 states and two countries, impacting more than 125 million people. We are poised for further growth as we expand into enterprise solutions and international markets.TeamAt Peregrine, our engineering team prioritizes empathy, believing it enhances our solutions. Observing how users interact with our product is essential as we navigate towards effective answers. Engineers will have the chance to collaborate onsite with our team, gaining insights into the diverse use cases we address.We cherish both ownership and teamwork—taking full responsibility for significant features while closely collaborating with fellow engineers to bring them to fruition. Humility and empathy are fundamental to developing optimal solutions, as we work directly with our deployment team and users to refine our offerings. Tenacity and creativity are vital in realizing our vision.RoleAs a pivotal member of our new AI team, you’ll play a key role in delivering unique value to our customers. This team is tasked with designing powerful, user-friendly experiences powered by generative AI. You will explore innovative methods for users to engage with our platform—whether through natural language commands or by enabling AI agents to manage complex tasks on their behalf. Your contributions will shape secure, impactful AI-driven features that assist clients in solving real-world issues more efficiently.Your responsibilities will encompass a variety of complex challenges, from scaling our platform to process terabytes of data from multiple sources to efficiently querying and alerting users in real-time, as well as optimizing search algorithms for quick results.Our tech stack is continuously evolving but is rooted in a backend framework of Python, Django, Celery, Airflow, and Kafka; a frontend constructed with React, Redux, and Mapbox; data storage solutions including PostgreSQL and Elasticsearch; machine learning models hosted in Bedrock and SageMaker; along with AWS, Pulumi, Terraform, and Kubernetes as our infrastructure.

Join Our Innovative Team at Retell AIRetell AI is at the forefront of revolutionizing the call center industry through advanced voice AI technology. In just 18 months since our inception, we have empowered thousands of businesses to optimize their sales, support, and logistics calls, which previously relied on large teams of human agents. Supported by prominent investors including Y Combinator and Alt Capital, we've achieved remarkable growth, scaling from $5 million to $36 million in annual recurring revenue (ARR) while expanding our talented team to 20 members.Our ambitious vision for 2026 is to develop a state-of-the-art customer experience platform, transforming entire contact centers with AI. Unlike traditional automation that requires ongoing human oversight, we are building intelligent AI "workers" capable of functioning as frontline agents, quality assurance analysts, and managers, constantly enhancing customer interactions.If you are a passionate innovator eager to solve complex technical challenges and make a tangible impact at one of the fastest-growing voice AI startups, we invite you to join us in shaping the future.Ranked among the top 50 AI applications by a16z: a16z List4th on Brex's Fast-Growing Software Vendors of 2025: Brex BenchmarkFeatured as a leading startup on: Leanaileaderboard

Join Us at Retell AIRetell AI is revolutionizing the call center industry by leveraging innovative voice AI technology based on first principles.In just 18 months since our inception, we have attracted thousands of companies that rely on Retell's AI voice agents to efficiently manage sales, support, and logistics calls, previously handled by large teams of human agents. Supported by renowned investors such as Y Combinator and Alt Capital, we have rapidly grown from $5M to $36M in Annual Recurring Revenue (ARR) with a dedicated team of 20.Looking ahead to 2026, our ambition is to establish a state-of-the-art customer experience platform entirely powered by AI. We aim to create intelligent AI “workers” capable of serving as frontline agents, quality assurance analysts, and managers, continuously optimizing customer interactions without the need for constant human oversight.We are on an exciting growth trajectory and are seeking driven individuals who are eager to solve complex technical challenges, accelerate progress, and make a significant impact at one of the fastest-growing voice AI startups.Let’s innovate the future together!Ranked as a top 50 AI app by a16z: https://tinyurl.com/5853dt2x#4 on Brex's Fast-Growing Software Vendors of 2025: https://www.brex.com/journal/brex-benchmark-december-2025One of the top startups on: https://leanaileaderboard.com/

midihealth seeks a Senior Software Engineer specializing in AI to join the team in a hybrid role based in the San Francisco Bay Area. This position centers on building and enhancing the company’s healthcare technology platform. Role overview This engineer will apply AI knowledge to develop new features and refine existing ones. The work involves collaborating with colleagues to design solutions that address real healthcare needs. Location This is a hybrid role. Candidates should be located in or able to commute to the San Francisco Bay Area.

About SentryAt Sentry, we are committed to transforming the way developers build software. With a mission to eradicate poor software experiences, we empower developers to create better applications more efficiently, ensuring a seamless encounter with technology.Backed by over $217 million in funding and trusted by more than 100,000 organizations, including industry giants like Disney, Microsoft, and Atlassian, we are at the forefront of performance monitoring and error tracking solutions. Our innovative tools enable companies to focus on product development rather than bug fixes.We embrace a hybrid work environment across our global offices, designating Mondays, Tuesdays, and Thursdays as in-office collaboration days to foster meaningful team interactions. If you are passionate about creating solutions that enhance the digital experience, join us in developing the next wave of software monitoring tools.About the RoleAs a Senior Software Engineer on Sentry’s AI/ML team, you will play a pivotal role in constructing the evaluation infrastructure that assesses the accuracy, reliability, and performance of our AI systems in real-world scenarios. This position is essential for ensuring that our debugging agents and AI-driven features operate correctly, safely, and predictably as they scale. You will design datasets, benchmarks, and test harnesses that convert vague AI behavior into quantifiable metrics, enabling the team to deploy AI solutions with confidence.In This Role You WillDevelop and implement robust evaluation frameworks to assess accuracy, reliability, regressions, and edge cases within AI systems.Generate and manage high-quality datasets, golden test cases, and benchmarks based on real production data.Create automated test harnesses and metrics pipelines to continuously evaluate models, prompts, and workflows.Collaborate closely with applied AI engineers and product leaders to establish clear definitions of success and translate them into measurable criteria.Oversee the evaluation lifecycle for significant AI projects, from initial experimentation to ongoing production monitoring.You'll Love This Job If YouHave a strong commitment to accuracy, rigor, and measurement in AI systems.Enjoy transforming ambiguous product objectives and model behaviors into precise tests and metrics.Take pleasure in building foundational infrastructure that facilitates rapid iteration and boosts team confidence.Thrive in collaborative environments and relish the opportunity to influence model design through effective evaluation.

Join Us in Combating the Escalating Wildfire Crisis with Cutting-Edge AI and IoT SolutionsAbout UsThe Challenge: In the face of climate change, wildfires are becoming more frequent and severe. Traditional methods of fire detection, reliant on bystanders and emergency calls, lead to critical delays in response times. Fire authorities require innovative solutions for faster detection, verification, and response to avert catastrophic fire outbreaks.Who We Are: Pano AI is a dynamic growth-stage startup based in San Francisco, comprising over 150 passionate professionals. We stand at the forefront of wildfire detection and intelligence, equipping fire services with timely information and advanced technology to enhance their response capabilities. Our platform integrates cutting-edge hardware, software, and AI, utilizing ultra-high-definition 360-degree cameras positioned strategically to provide real-time threat assessments. Our technology empowers fire professionals with actionable insights, enabling them to prevent minor flare-ups from escalating into significant disasters.Recognized by TIME as one of the 100 Most Influential Companies of 2025, and featured in MIT Technology Review's top 15 climate tech companies to watch, Pano AI is paving the way for innovative solutions in fire response. Our contributions have been recognized in major publications such as the Wall Street Journal and Bloomberg.

About Scale AIAt Scale AI, we are dedicated to revolutionizing the development of artificial intelligence applications. For eight years, we have established ourselves as the foremost AI data foundry, driving groundbreaking advancements in areas such as generative AI, defense applications, and autonomous vehicles. With our recent Series F funding round, we are poised to enhance the availability of frontier data, paving the way towards Artificial General Intelligence (AGI). Our commitment extends to refining our model evaluation expertise for enterprise clients and government entities, thereby enriching our capabilities for both public and private assessments.About the Generative AI Data EngineOur Generative AI Data Engine empowers the most sophisticated LLMs and generative models through premier Reinforcement Learning with Human Feedback (RLHF), human data generation, model evaluation, safety, and alignment. The data we generate is pivotal for shaping humanity's interaction with artificial intelligence.Our ApproachDuring the interview process, candidates may be considered for various roles across different teams within the GenAI Engineering organization based on their skills, interests, and business needs. Potential placements include Allocation, Growth, Frontier Data, Trust & Safety, Pay, Operator, or Tasking Experience. These teams are instrumental in scaling Scale AI’s operations - from curating impactful datasets that enhance LLM capabilities to optimizing contributor onboarding and ensuring data integrity through advanced safety and security protocols. They operate at the crossroads of machine learning, operations, and analytics to guarantee that we deliver top-tier data at scale.Key Responsibilities:Design, develop, and maintain robust, scalable systems across the entire stack, including front-end, back-end, and infrastructure.Implement high-impact features using contemporary technologies such as TypeScript, React, Node.js, MongoDB, Elasticsearch, and Temporal.Work collaboratively with internal operators to identify bottlenecks and deliver rapid, effective solutions.Take ownership of core systems crucial to our contributor platform, directly influencing Scale’s GenAI data pipeline and overall business outcomes.Architect and scale infrastructure to manage millions of tasks weekly with high reliability and low latency.Collaborate cross-functionally with ML teams, Forward Deployed Engineers, and Product to maintain data quality and operational excellence.Contribute to fostering a robust engineering culture while setting best practices for peers through mentorship, code reviews, and process improvement.

zip seeks a Senior Software Engineer with a focus on Internal AI to strengthen internal systems and processes. This position is based in San Francisco and centers on building software that supports the company's operations. Role overview This engineer will design, build, and refine AI-driven software tailored for internal use. The work involves collaborating with teams across zip to understand their needs and deliver solutions that improve workflows and efficiency. What you will do Create and enhance software powered by AI for internal operations Partner with colleagues from different departments to identify requirements and deliver effective tools Participate in all phases of the software development lifecycle, including planning, development, and deployment Maintain high standards for reliability and organizational quality Address technical challenges and solve problems using AI technologies Requirements Solid background in software engineering and artificial intelligence Experience working with cross-functional teams Proven ability to write high-quality, maintainable code Interest in using technology to improve internal business processes

About UsAt Imprint, we are revolutionizing co-branded credit cards and financial services to be more intelligent, rewarding, and brand-centric. Collaborating with renowned brands such as Crate & Barrel, Rakuten, and Booking.com, we create modern credit solutions that enhance customer loyalty, generate savings, and drive business growth. Our innovative platform integrates cutting-edge payment infrastructure, smart underwriting, and user-friendly interfaces, enabling brands to offer impactful financial products without the complexities of traditional banking.With co-branded cards representing over $300 billion in U.S. spending annually, Imprint stands out as the modern alternative—flexible, technology-driven, and designed for today’s consumer. Supported by leading investors like Kleiner Perkins and Thrive Capital, we are building a dynamic team to transform payment experiences and empower brand growth. If you are eager to work in a fast-paced environment, tackle complex challenges, and make a significant impact, we would love to connect with you.Your RoleWe are seeking an innovative and technically adept Senior AI Software Engineer to develop our agent platform at Imprint and spearhead the deployment of our first 50 agents. This initiative aims to enhance the efficiency of our internal teams and processes. As an AI Engineer, you will be tasked with evolving the agent platform from basic functionalities to essential capabilities. You will leverage a range of existing AI tools, including ChatGPT and Notion AI, to implement advanced LLM techniques throughout the organization.Your role will encompass end-to-end development, collaborating with various departments to seamlessly integrate internal systems and deliver valuable, secure agent-based interfaces. We trust you to act swiftly, experiment boldly, and scale successful initiatives.The ideal candidate is a proactive problem-solver who thrives in uncertainty, enjoys building, and knows how to harmonize practicality with technical vision. You should be comfortable with tasks ranging from API integration to managing embeddings or RAG pipelines. This position demands a combination of customer-focused product development, hands-on experience with contemporary AI frameworks, software engineering principles, and a passion for automation. If you are excited about the opportunity to create significant leverage across a growing organization, we would love to meet you.Your ResponsibilitiesPlatform & Agent DevelopmentDesign and implement the agent platform that supports internal processes.Lead the development and deployment of agent capabilities, ensuring they meet business needs.Collaborate with teams across the company to enhance system integrations.Conduct experiments to identify and scale successful AI solutions.

Join our innovative team at Mercury as a Senior Software Engineer specializing in AI Enablement. In this pivotal role, you will leverage your expertise in artificial intelligence to drive transformative solutions that enhance our products and platforms. Collaborate with cross-functional teams to design, develop, and implement cutting-edge AI features that meet our users' evolving needs.We are looking for a candidate who thrives in a fast-paced environment, possesses a strong understanding of AI technologies, and is passionate about creating impactful software solutions. Your contributions will be essential in shaping the future of our offerings and delivering exceptional user experiences.

About the RoleHinge Health is a leading digital health company dedicated to delivering innovative, evidence-based solutions for musculoskeletal (MSK) pain management. Our unique approach combines personalized exercise therapy with virtual care, empowering individuals to effectively manage chronic pain and enhance their quality of life, all while reducing healthcare costs. By partnering with employers and health plans, we aim to scale our solutions and improve overall employee health and productivity.Join our dynamic AI platform team at Hinge Health, where we are at the forefront of revolutionizing how businesses harness the power of Artificial Intelligence. We are searching for a Senior Software Engineer with a robust background in software engineering and a passion for AI to contribute to our mission.As a Senior Software Engineer, you will play a crucial role in developing and maintaining vital components of our AI infrastructure. You will collaborate closely with engineers and data scientists to ensure the platform effectively supports the intricate needs of AI models and machine learning workflows.Our team thrives in a continuous deployment DevOps culture, taking pride in maintaining high standards of code in production. Our production systems leverage technologies such as React Native, React, Node.js, TypeScript, Python, Nestjs, GraphQL, Docker, AWS, Postgres, Redis, Apollo, and Redux. We follow a trunk-based CI/CD workflow and uphold the highest security and compliance standards, including HIPAA, HITRUST, SOC 2, and CCPA.What You'll AccomplishCollaborate with the AI/ML team to effectively integrate models and agents into the platform, ensuring seamless deployment.Write clean, maintainable code with a focus on performance, reliability, and scalability.Develop and sustain APIs and microservices that facilitate AI model and agent deployment and data processing.Troubleshoot and resolve platform performance, integration, and reliability issues.Work alongside cross-functional teams to gather technical requirements and deliver efficient solutions.Contribute to ongoing improvements in the AI platform’s systems and workflows, providing ideas and feedback during architectural discussions.Hinge Health Hybrid ModelWe recognize that both remote and in-person work offer unique benefits, and we aim to capitalize on the strengths of both approaches. Employees in hybrid roles enjoy the flexibility of working from home while also engaging in person as needed.

Employee Applicant Privacy NoticeWho We Are:Join us in shaping a brighter financial future.At SoFi, we are redefining personal finance by transforming the way individuals engage with their financial journeys. As a cutting-edge financial services provider and national bank, we leverage innovative, mobile-first technology to empower our millions of members to achieve their aspirations. In a rapidly evolving industry, we pride ourselves on making a meaningful impact on the lives of our members while adhering to our core values. Invest in your future with SoFi and be part of the financial revolution.The Role:We are seeking a seasoned Senior Principal Software Engineer to provide strategic AI leadership within SoFi’s technology division. In this pivotal position, you will significantly influence and guide the AI enablement strategy in collaboration with key engineering and data science leaders. Your focus will be on promoting best practices in AI applications across diverse domains, especially in software development and back-office operations. You will lead the vision for infrastructure and methodologies essential for supporting these initiatives, ensuring rapid adoption of the latest foundational model capabilities and emerging best practices. To achieve this, you will implement a build-over-buy strategy to minimize friction from reliance on third-party vendors while making judicious investments in those that can expedite our delivery and foster future innovation.This is an exciting opportunity to tackle complex challenges within a dynamic, collaborative, and innovative environment. The ideal candidate will be a thought leader in AI applications for software development, capable of impacting both technical and non-technical team members. You should possess a strong background in mentoring and skill development across our organization and advocate for the integration of AI alongside traditional techniques to enhance both velocity and quality. You will be expected to lead prototype development and production solutions as necessary to facilitate widespread organizational changes.What You’ll Do:Technical Leadership: Provide visionary guidance on enabling and integrating AI throughout the organization.Strategic Partnerships: Collaborate with cross-functional teams to identify and implement AI solutions.

About UnifyUnify is revolutionizing the way revenue teams operate by developing the first AI-powered system of action. Our mission is to transform outbound strategies into a robust growth engine, ensuring that go-to-market execution is observable, repeatable, and scalable. Established in 2023 by industry leaders from Ramp and Scale AI, our talented team boasts backgrounds from renowned companies like Airbnb, Meta, Waymo, and Perplexity.In 2024, Unify achieved an impressive 8x revenue growth and serves a diverse clientele including Perplexity, Cursor, SoFi, and Justworks. We are a dynamic team fueled by high energy and intensity, having secured $58M in funding from leading investors such as Thrive, Emergence, and OpenAI. Join us in shaping the future of GTM!About the Role:As a Senior Software Engineer specializing in AI at Unify, you will be at the forefront of innovation, developing new AI products and enhancing our AI platform. Your work will encompass agents, retrieval systems, classification, fine-tuning, reinforcement learning, and LLM inference infrastructure. If you are passionate about creating production-ready AI systems and wish to contribute to cutting-edge applications used by premier GTM teams, this role is for you.