Senior Full Stack Software Engineer at Retell AI | San Francisco

Join Aircall as a Senior Software Engineer specializing in AI Voice Agents, where you'll play a pivotal role in designing and implementing innovative voice solutions. Your expertise in software development and artificial intelligence will help us enhance customer interactions through cutting-edge technology.

Join Deepgram, a pioneering leader in voice AI technology, as a Software Engineer specializing in Voice Agents for the restaurant industry. You will play a vital role in developing innovative AI applications that enhance customer experiences and streamline restaurant operations. Your expertise in software development and passion for AI will contribute to transforming how restaurants interact with their customers.

About Sage CareSage Care is a dynamic and rapidly expanding healthcare startup, founded by a team of visionary leaders from major tech companies like Apple, Uber, and Carbon Health, and supported by esteemed venture capital firms including General Catalyst and Chelsea Clinton. Our mission is to revolutionize healthcare by streamlining care navigation, making it accessible and efficient for everyone.Our innovative platform empowers patients to easily locate the right healthcare providers and enables clinicians to prioritize those who require assistance the most. By leveraging cutting-edge AI technologies, we ensure that patients have quicker access to care, leading to improved health outcomes and significant economic advantages at scale.Having established successful partnerships with healthcare systems across the U.S., we are now extending our reach internationally, particularly in the MENA region, where we are collaborating with local health systems to implement our AI-driven care navigation solutions.About the RoleWe are seeking a highly skilled Staff AI Engineer to spearhead the design and advancement of our AI voice agents. This pivotal role will involve creating and managing AI systems that perform effectively in real-world environments.You will be responsible for the comprehensive behavior of our agents, overseeing their orchestration, tool utilization, latency, evaluation, and the management of failures.Your work will involve tackling complex, non-deterministic systems, crafting an architecture that ensures consistency, observability, and scalability in production settings.What You’ll DoDesign and oversee the architecture of AI agents, encompassing orchestration, tool usage, and control flow.Create systems that guarantee reliable agent operation across diverse real-world interactions.Develop and refine evaluation frameworks to assess agent quality and behavior.Identify and troubleshoot complex issues in production, including edge cases, failures, and regressions.Enhance performance across the system stack, focusing on latency, cost, and reliability.Establish patterns and best practices for building and operating AI agents.Mentor fellow engineers and elevate the standards of AI systems design and execution.What We’re Looking ForRequired QualificationsMinimum of 7 years of experience in software engineering.Proven experience in developing and managing AI agents or conversational systems in production settings.Deep understanding of:Agent orchestration and control mechanisms.Real-world systems and their operational challenges.

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/

Baseten creates AI inference solutions for clients such as Cursor, Notion, OpenEvidence, Abridge, Clay, Gamma, and Writer. The team blends AI research, infrastructure, and developer tools to help organizations deploy advanced models. Backed by $300M in Series E funding from BOND, IVP, Spark Capital, Greylock, and Conviction, Baseten is expanding quickly and shaping the landscape for engineers building AI products. Role overview The Software Engineer - Voice AI role centers on building and deploying open-source voice models for real-world use. Voice is becoming a key interface across the web, and this position addresses the technical challenges of bringing production-ready Voice AI to market. The work supports applications in productivity, customer service, clinical dialogue, creator tools, education, and more, helping to change how people interact with technology across sectors. This engineer leads Baseten’s Voice AI efforts, guiding the proprietary inference stack that powers Voice AI models. The role balances shaping the product roadmap with hands-on engineering. Collaboration is a core part of the job, working closely with Forward Deployed Engineers, Model Performance Engineers, and other technical teams to advance Voice AI capabilities. Sample projects and initiatives The world's fastest Whisper, with streaming and diarization Canopy Labs selects Baseten for Orpheus TTS inference Partnering with the Core Product team to build an orchestration framework for a multi-model voice agent Working with the Training Platform team to support ongoing training of voice models Designing a developer-friendly API and SDK to encourage self-service adoption of Baseten Voice AI products Location San Francisco

About Tenable:Tenable® is at the forefront of Exposure Management. With 44,000 organizations worldwide counting on us to mitigate cyber risk, we empower 65% of the Fortune 500, 45% of the Global 2000, and numerous governmental agencies. Join us in redefining the cybersecurity landscape!Why Choose Tenable?When you ask our team about what makes Tenable a fantastic workplace, the answer is simple: our people! Together, we innovate cutting-edge cybersecurity solutions, fostering a culture of inclusion, respect, and excellence. As part of the #OneTenable team, you'll collaborate with some of the industry's most talented professionals while having access to the resources necessary to make a meaningful impact. We strive to deliver exceptional results and celebrate our victories together!Note: Applicants must be authorized to work in the U.S. without sponsorship. We currently cannot sponsor work visas.Location: Must reside in or be willing to relocate to the San Francisco/San Jose area.Your Role:At Tenable, we're not just creating exceptional products; we're cultivating a premier engineering culture dedicated to hiring top talent. We are seeking a Senior Software Engineer to be part of a pioneering initiative within our engineering team. In this role, you will design and implement the Agentic AI Platform, an orchestration layer that empowers autonomous agents to reason, plan, and execute intricate security workflows within our Exposure Management ecosystem.This role is highly hands-on and has a significant impact. You won't merely be utilizing LLMs; you'll be constructing distributed systems, state machines, and tools that transform generative models into reliable, enterprise-grade agents.While this role is primarily remote, occasional in-person meetings may be necessary.Your Opportunity:Construct the Agentic Backbone: Design and implement backend services that facilitate multi-agent workflows, enabling AI agents to break down complex user requests, manage states, and execute tasks across distributed microservices....

ABOUT THE ROLE:As an AI Engineer at Varick, you will take charge of designing and optimizing the intelligence layer within our enterprise operations. This involves creating agent systems that efficiently handle thousands of transactions, make classification decisions, and learn from human interactions.This position is suited for engineers with extensive experience in LLMs, agent architectures, and evaluation systems. You have successfully developed agent workflows that operate in production, not merely in demo environments. Your expertise includes prompt engineering, retrieval, tool calling, multi-agent orchestration, and the evaluation frameworks necessary for deploying trustworthy AI systems in enterprise settings.WHAT YOU'LL DO:• Design and implement agent architectures that tackle complex enterprise workflows, focusing on multi-step reasoning, tool calling, and exception handling.• Develop and sustain evaluation systems that ensure agent quality, accuracy, safety, and groundedness.• Create robust prompt systems, retrieval pipelines, and context engineering strategies to ensure reliable agent performance.• Establish feedback loops that empower agents to learn from human corrections and enhance their functionality over time.• Optimize inference costs and latency for production workloads to ensure efficiency.• Define and uphold best practices for agent reliability, observability, and governance.• Stay updated with the latest models, frameworks, and research to ensure impactful deployments into production.WHAT WE'RE LOOKING FOR:• At least 3 years of software engineering experience, with a minimum of 1–2 years dedicated to LLM applications or AI systems in a production environment.• Practical experience in constructing agent workflows featuring tool calling, retrieval, and multi-step reasoning.• A profound understanding of prompt engineering, context engineering, and methods to elicit reliable behavior from LLMs.• Experience in developing evaluation systems to assess AI output quality.• Proficient in Python with a solid foundation in backend engineering principles.• You have delivered AI features to actual users and have navigated challenges such as hallucinations, edge cases, accuracy drops, and cost management.• Must be based in San Francisco.

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.

About Nooks.ai:Nooks is revolutionizing the sales landscape with our AI Sales Assistant Platform (ASAP) that streamlines operations, allowing sales representatives to concentrate on building meaningful customer relationships and boosting their sales pipeline. Our innovative platform has empowered thousands of sales professionals to achieve their quotas, saving clients countless hours and generating hundreds of millions in revenue. Trusted by sales teams at leading companies like Hubspot, Rippling, and Toast, Nooks is at the forefront of sales technology.Backed by over $70M in funding from premier venture capitalists, including Kleiner Perkins, Nooks is experiencing exceptional growth, having increased our Annual Recurring Revenue (ARR) by 4x and then 3x in recent years. We aim to achieve another 3x growth this year, continuing our trajectory of success.For more information, visit Nooks.ai.As a Senior Software Engineer specializing in voice AI, you will take ownership of our backend infrastructure for real-time audio/video communication, ensuring it scales efficiently to handle increased usage.Responsibilities:Design and enhance real-time voice infrastructure utilizing WebRTC, SIP, and Twilio.Monitor and optimize call quality and latency to comply with global SLA targets.Develop advanced features including call transfers, monitoring, and recordings.Create observability and debugging tools to streamline call flow management.Collaborate with Product and Support teams to facilitate new A/V feature rollouts and expedite issue resolution.Qualifications:6–10+ years of experience in backend or infrastructure engineering, specifically in real-time audio/video or telephony systems.Proven expertise with WebRTC, SIP, Twilio, or similar technology stacks.Solid understanding of distributed systems and low-latency infrastructure.Experience in debugging and optimizing Quality of Service (QoS) metrics such as latency, jitter, and packet loss.Compensation at Nooks for qualified roles includes a competitive base salary, equity options, and a comprehensive benefits package. Our offerings include health, dental, vision, life, and disability insurance coverage, a flexible hybrid work environment, and unlimited paid time off. Benefits may vary based on location and are subject to change.

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

About the RoleHex Technologies is seeking experienced Senior and Staff-Level Fullstack Engineers who are passionate about contributing to our revolutionary Magic AI features.At Hex, we are dedicated to developing integrated AI functionalities that enhance and expedite analytics workflows. The potential here is extraordinary, and we are in a unique position to transform how individuals interpret and utilize data.In this position, you will spearhead the integration of AI-driven features into the Hex platform, collaborating closely with our Research Team for context and model prompting, as well as with other product engineering teams for seamless integration. Your efforts will significantly alter the data interaction experience for thousands of users, placing you at the forefront of one of the most exciting technological evolutions of our time. As a member of our Agent Platform Team, you will manage the scalable infrastructure that powers today's most advanced data agents and the innovative experimentation tools that enable rapid development of new AI features.

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/

About Aqua VoiceAqua Voice is pioneering the voice input landscape for the AI era. By training our own models and creating deep OS integrations, we ensure that voice technology is executed flawlessly across the entire stack.The evolution of work is upon us; individual contributor roles are transforming as we now manage AI agents, a task that naturally aligns with voice interactions.We are not focused on traditional conversational agents; instead, we champion a voice-in-text-out (VITO) approach, believing that voice functionality should operate above traditional applications, and that innovative startups can lead in this domain.With an unwavering commitment to this vision, our progress has been promising, and we invite you to be a part of our journey.The RoleAs a growing team, you will have the opportunity to engage with all facets of our system.Recent projects include:Development of a real-time transcription server capable of managing thousands of concurrent audio streams.Training and deploying custom speech recognition models.Creating native integrations for macOS and Windows utilizing advanced system APIs.Technology StackFrontend: TypeScript, React, Next.js, ElectronBackend: Python, real-time server (Bun/Node.js), WebSocketsNative: Swift (macOS), C# (Windows)Machine Learning: Custom speech recognition models, inference pipelinesInfrastructure: Terraform, StripePrior experience with all these technologies is not required.Qualifications- Showcase your previous work and projects.- Adaptable in switching between programming languages and domains.- Capable of taking ownership of projects from concept to production.- Proficient in writing clean and maintainable code.- Experience with production systems is essential.- A positive attitude and a collaborative spirit are a must!

Why Choose Flux?At Flux, we are transforming the landscape of hardware development by pioneering the world's first AI Hardware Engineer. Our mission is to democratize access to cutting-edge hardware creation and transform the way electronics are designed and manufactured globally.About the RoleWe are on a quest to build the first AI Hardware Engineer, software capable of designing tangible, manufacturable electronics from simple prompts. As a Senior Software Engineer focusing on Agentic Development, you will be responsible for creating the system's intelligence, developing agentic workflows, reasoning graphs, and integrations that empower both novice and experienced engineers in their journey from concept to manufacturable hardware.This position fuses advanced web engineering with AI systems design. You will leverage TypeScript and LangGraph within the Flux web application and backend platform, embedding intelligent features directly into the design environment.Key ResponsibilitiesDevelop and implement agentic reasoning capabilities using TypeScript (LangGraph).Integrate AI functionalities into the Flux web application (React/Redux) and Chat UI.Implement telemetry and logging for monitoring runtime health, performance, and cost efficiency.Collaborate closely with product and electrical engineers to refine intelligent ECAD workflows.Conduct evaluations and translate insights into engineering decisions.Contribute to the development of agentic patterns, conventions, and best practices within the engineering organization.Required Qualifications8+ years of experience in software engineering, with at least 1 year in developing generative-AI or agentic systems.Proficient in TypeScript, React, and Node.js.Experience with LangChain, LangGraph, or similar orchestration frameworks.Proven track record in building asynchronous, distributed systems in a production environment.Experience in integrating LLM-based systems into complex user-facing web products.Strong communication skills and comfort working in a fully remote, asynchronous team setting.Previous experience in a startup or in 0→1 product development environments.Preferred QualificationsFamiliarity with retrieval systems, evaluation pipelines, or agent benchmarking.

Join Perplexity as a dynamic AI Software Engineer on our innovative Comet Agents engineering team. We are a tight-knit group of AI/ML specialists, backend developers, and full-stack engineers dedicated to creating engaging agentic experiences within our Comet ecosystem. Our mission is to empower users with AI agents that genuinely understand and fulfill their intents, enabling seamless, open-ended interactions with the digital world.As a key contributor to the Comet Agents team, you will apply your AI expertise, product intuition, and creative problem-solving skills to push the boundaries of what AI agents can achieve for our millions of loyal users. Your work will span applied research and engineering, tackling various challenges in AI, including:Crafting AI agents capable of navigating the digital landscape and executing valuable tasks for users;Developing action and decision models that effectively achieve user-defined objectives based on complex multimodal states;Delivering exceptional user experiences across desktop, mobile, headless cloud, and more, utilizing flexible abstractions and seamless background processes;Implementing secure-by-design capabilities through the creation of permission architectures and payload classifiers;Designing optimal data representations and interaction modes between agents and their environments;And much more!ResponsibilitiesLead the development of cutting-edge AI functionalities within our rapidly evolving AI agents product.Utilize advanced AI models, infrastructure, and browser technologies to enhance capabilities for our expanding user base.Uphold high standards of quality and performance in AI agents and user experience.Collaborate with engineers, designers, product managers, and data scientists to integrate core Perplexity functionalities into Comet agents.Contribute to product reliability, code quality, AI evaluation, testing, and ongoing maintenance across the team.QualificationsSolid foundational knowledge of the complete AI product stack.Experience with AI/ML frameworks and backend development.Proficiency in programming languages commonly used in AI development.Ability to work collaboratively in a fast-paced, interdisciplinary environment.Strong problem-solving skills and a passion for innovation in AI technologies.

About DecagonDecagon stands at the forefront of conversational AI, empowering brands to create unparalleled customer experiences. Our platform enables leading enterprises such as Avis Budget Group, Block’s Cash App, Square, Chime, Oura Health, and Hunter Douglas to deploy AI agents that facilitate personalized, engaging interactions across voice, chat, email, SMS, and beyond.We envision a world where customer interactions transcend traditional support tickets and hold music, fostering quicker resolutions, richer dialogues, and stronger relationships. Our esteemed investors, including a16z, Accel, Bain Capital Ventures, Coatue, and Index Ventures, share this vision and support our mission.As an in-office company, we are united by our commitment to excellence and rapid execution. Our core values — Just Get It Done, Invent What Customers Want, Winner’s Mindset, and The Polymath Principle — guide our collaborative work environment and team growth.About the TeamThe Agent Orchestration team is responsible for developing the foundational execution layer that drives every agent interaction. We create systems that coordinate model reasoning, assess agent behavior, and ensure reliability in real-world customer scenarios. Our focus on accuracy, dependability, and speed enables Decagon agents to plan, decide, and act effectively across millions of interactions.About the RoleAs a Senior Software Engineer on the Agent Orchestration team, you will design and develop systems that govern the performance of Decagon agents in real-world conditions. You will tackle complex challenges associated with distributed systems and lay the groundwork for enhancing agent performance, reliability, and quality.This role offers significant autonomy and the opportunity to make a direct impact on the architecture of one of the most sophisticated agent platforms globally.In this role, you will:Develop the execution engine that supports intelligent agents at scale.Design systems that synchronize model reasoning and actions while maintaining speed and accuracy.Enhance reliability through improved testing, observability, and safety measures.Establish foundations that enable teams to evaluate and enhance agent behavior safely and continuously.

ABOUT RETELL AIRetell AI is at the forefront of revolutionizing call centers with innovative voice AI technology, utilizing first principles to redefine customer interactions.In just 18 months since our inception, thousands of companies have adopted Retell's AI voice agents to manage sales, support, and logistics calls that previously required extensive human teams. Supported by prestigious investors such as Y Combinator and Alt Capital, we have rapidly scaled to $36M ARR with a lean team of 20, up from $5M at the start of 2025.Our vision for 2026 is to create a modern customer experience (CX) platform where entire contact centers are powered by AI, moving beyond basic automation that relies on constant human intervention to intelligent AI “workers” that operate as frontline agents, quality assurance analysts, and managers, continuously executing, monitoring, and enhancing customer interactions.As we grow, we seek passionate builders eager to tackle challenging technical problems, accelerate progress, and make a genuine impact within one of the fastest-growing voice AI startups.Join us in shaping the future.Ranked among the top 50 AI applications in a16z's list: https://tinyurl.com/5853dt2x#4 on Brex's Fast-Growing Software Vendors of 2025: https://www.brex.com/journal/brex-benchmark-december-2025Also recognized as a top-ranking startup on: https://leanaileaderboard.com/ABOUT THE ROLEAs a Senior Software Engineer - Support Automations at Retell, you will take charge of the technical support for our advanced, agentic voice AI platform. This hands-on leadership role involves personally troubleshooting complex customer issues, developing AI agents and automations, and guiding a growing team of support engineers.You will work at the intersection of engineering, customer relations, and product development, ensuring exceptional reliability, swift resolutions, and scalable support as Retell expands.This position is perfect for someone who thrives on solving intricate technical challenges in high-pressure environments, engages directly with customers, and enjoys building systems and teams from the ground up.

Join our team at Anthropic as a Senior / Staff+ Software Engineer specializing in Voice Platform development. In this role, you will be instrumental in advancing our voice technology initiatives, working closely with cross-functional teams to create innovative solutions that enhance user experiences.

Baseten seeks a Software Engineer to focus on Voice AI within the Inference Runtime team. This San Francisco-based role centers on building and refining AI models that power voice interaction features in Baseten products. Role overview This position involves hands-on work with AI models for voice-driven applications. The engineer will help shape how users interact with voice technology by developing and optimizing the underlying systems. What you will do Develop and optimize AI models for applications that use voice as a primary interface Work on inference runtime systems to support responsive and intelligent voice experiences Contribute directly to Baseten's products, influencing the future of voice technology for users Location This position is based in San Francisco.