Senior Backend Software Engineer at Retell AI | 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.

About Us:At LangChain, we are dedicated to making intelligent agents a fundamental part of everyday technology. Our mission is to provide the essential tools for agent engineering in practical applications, enabling developers to transition seamlessly from initial prototypes to production-ready AI agents that organizations can depend on. Starting as a suite of widely adopted open-source tools, we have expanded to offer a comprehensive platform for building, evaluating, deploying, and managing AI agents at scale.Currently, our platforms, including LangChain, LangGraph, LangSmith, and Agent Builder, are trusted by teams developing real AI solutions in both startups and established enterprises. Our technology powers AI initiatives for renowned companies such as Replit, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, and 35% of the Fortune 500.With $125M raised in Series B funding from IVP, Sequoia, Benchmark, CapitalG, and Sapphire Ventures, we are at an exciting juncture where we continue to innovate, grow rapidly, and every team member can make a significant impact on our products and collaboration. Join us at LangChain, where your contributions can reshape the technology landscape.About the Role:In-person, 5 days a week in San FranciscoWe are seeking a Fullstack Engineer to join our LangSmith product team, focusing on our commercial AI observability and evaluation platform. In this position, you will have the opportunity to develop new features and capabilities for our platform while collaborating closely with enterprise clients, developer end-users, and internal stakeholders.Your Responsibilities:Design and implement critical product features utilizing our Go, Python, and TypeScript stackWork in close partnership with product and design teams to refine features and enhance the product roadmapDrive project timelines effectively while maintaining high engineering standards through clean, maintainable, and well-tested codeTo Succeed in This Role:2+ years of experience in software engineering, particularly with complex platform productsFullstack engineering experience with Go or Python on the backend and React + TypeScript on the frontendStrong understanding of database systems, especially Postgres and RedisExperience in designing and scaling APIs, ideally in high-performance environments

About Our TeamJoin the dynamic Support Automation team at OpenAI, where we utilize cutting-edge AI technologies to tackle real-world challenges and automate processes across our organization. Our mission is to enhance productivity from customer operations to engineering by building a suite of automation tools that empower our team members. We are dedicated to creating innovative products that prioritize quality and reliability through rapid prototyping and reusable solutions applicable across various sectors within OpenAI.In summary, our team harnesses OpenAI's technology to improve our internal processes, and you will have the unique opportunity to access both public and pre-released technologies to achieve this goal.About the RoleWe are seeking a talented Backend Software Engineer with substantial experience in machine learning and large language models to help us design and implement an evaluation infrastructure that measures the effectiveness of OpenAI's support automation efforts. This role is highly technical and collaborative, requiring you to build resilient systems and backend services that underpin knowledge creation, access, and application throughout OpenAI. You will work closely with Data Science and Research teams to scale evaluations effectively.Key Responsibilities:Design and implement evaluation pipelines that are dependable, reproducible, and scalable.Develop infrastructure for continuous evaluation monitoring, including regression and drift monitoring, and establish robust feedback loops to enhance support automation.Create, maintain, and support backend services and APIs that facilitate intelligent automation and knowledge systems.Integrate and organize data across internal platforms, optimizing it for downstream systems and AI workflows.Collaborate closely with data, research, and engineering teams to effectively integrate OpenAI models into impactful workflows.Oversee the full development lifecycle of new backend systems and internal platform features.Design with scalability and maintainability in mind while iterating rapidly on innovative ideas.Ideal Candidate Profile:4+ years of experience in backend engineering within product-focused companies (excluding internships).Proficient in designing and building reliable backend systems, with a strong understanding of machine learning principles.Experience collaborating across teams to drive project success and impact.

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/

About Us:At LangChain, we are dedicated to making intelligent agents a fundamental part of everyday technology. Our platform serves as a robust foundation for agent engineering in real-world applications, empowering developers to transition from initial prototypes to production-ready AI agents that are dependable for teams. Starting as widely embraced open-source tools, we have evolved into a comprehensive platform for building, evaluating, deploying, and managing agents on a large scale.Our offerings, including LangChain, LangGraph, LangSmith, and Agent Builder, are trusted by teams delivering real AI products across both startups and major corporations. Millions of developers utilize LangChain to enhance AI capabilities at companies such as Replit, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, and 35% of the Fortune 500.With $125M raised in Series B funding from reputable investors like IVP, Sequoia, Benchmark, CapitalG, and Sapphire Ventures, we are poised for continued growth and innovation. Each team member plays a crucial role in shaping the technologies we develop and the collaborative culture we foster at LangChain.About the Role:This is an in-office position requiring presence in San Francisco, Boston, or New York City five days a week.We are seeking a Senior Backend Engineer to join our team. In this role, you will be responsible for developing the backend systems that drive LangChain’s observability and evaluations platform. Your work will focus on core services that enable developers to monitor and assess their AI applications on a large scale. While your primary responsibilities will involve backend feature development, experience with full-stack or frontend engineering, performance optimization, and troubleshooting production issues will be highly beneficial.Key Responsibilities:Design, develop, and maintain backend services and APIs to facilitate LangSmith’s tracing, monitoring, and evaluation workflows.Collaborate on architectural decisions to ensure systems are both high-performing and maintainable.Optimize storage and query performance for high-volume observability and evaluation data.Ensure system reliability with robust testing, monitoring, and alerting practices.Diagnose and resolve production issues, conducting root-cause analysis and implementing lasting solutions.Produce and maintain comprehensive technical documentation, including system design and API references.

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 Scale AI as a passionate and technically adept AI Research Engineer within our Enterprise Evaluations team. This pivotal role is integral to our goal of providing the industry's leading Generative AI Evaluation Suite. You will actively contribute to the foundational systems that guarantee the safety, dependability, and ongoing enhancement of LLM-driven workflows and agents for enterprise clients. The perfect candidate will possess a robust understanding of large language models, a fervor for addressing intricate evaluation dilemmas, and the ability to excel in a fast-evolving research atmosphere. We seek an engineer who can innovate, remains informed about the latest studies in AI evaluation, and is enthusiastic about incorporating cutting-edge research concepts into our workflows to create top-tier evaluation systems.

About Us:LangChain is dedicated to making intelligent agents commonplace. We are pioneering the foundations of agent engineering in the real world, empowering developers to transition from prototypes to production-ready AI agents that teams can depend on. Initially known for our widely embraced open-source tools, we have expanded to provide a comprehensive platform for constructing, assessing, deploying, and managing agents at scale.Our products, including LangChain, LangGraph, LangSmith, and Agent Builder, are utilized by teams delivering genuine AI solutions in both startup environments and large corporations. Millions of developers trust our technology to elevate AI initiatives at organizations such as Replit, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, and 35% of the Fortune 500.With $125M raised in our Series B funding from IVP, Sequoia, Benchmark, CapitalG, and Sapphire Ventures, we are poised for continued product development and accelerating growth, where each team member plays a significant role in shaping our technology and collaborative culture.About the Role:On-site 5 days a week in San FranciscoWe are seeking a Senior Fullstack Engineer for our commercial product, LangSmith, which serves as an observability and evaluation platform. In this role, you will have the chance to influence the technical direction of our platform while engaging with enterprise clients, developer end-users, and internal stakeholders.Lead the technical architecture and implementation of essential product features for LangSmith, utilizing our entire stack of Go, Python, and TypeScript.Work closely with product and design teams to iterate and refine new features.Mentor and support junior team members, driving ambitious project timelines while upholding high engineering standards.Set an example by producing clean, maintainable, and thoroughly tested code.

About Us:At LangChain, we are dedicated to making intelligent agents a common part of everyday technology. Our goal is to provide a robust foundation for agent engineering that empowers developers to transition from prototypes to production-ready AI agents that teams can depend on. Initially starting as a widely embraced open-source toolset, we have expanded our offerings to include a comprehensive platform for the building, evaluating, deploying, and managing of agents at scale.Currently, our tools—LangChain, LangGraph, LangSmith, and Agent Builder—are utilized by teams developing real AI products in both startups and large enterprises. Millions of developers rely on LangChain to power AI initiatives at notable companies such as Replit, Clay, Coinbase, Workday, Lyft, Cloudflare, Harvey, Rippling, Vanta, and 35% of the Fortune 500.Having secured $125M in Series B funding from leading investors like IVP, Sequoia, Benchmark, CapitalG, and Sapphire Ventures, we are in an exciting phase of product development and rapid growth, where every team member has a substantial impact on our projects and collaborative efforts. At LangChain, your contributions will play a crucial role in shaping how this technology manifests in the real world.About the Role:This position requires in-person attendance 5 days a week in San Francisco, CA, as well as options in New York and Boston.We are seeking a seasoned frontend engineer to innovate and improve features on LangSmith, our enterprise platform designed for LLM application observability, testing, and debugging.What You Will Do:Create new user-facing features utilizing React and TypeScript.Develop reusable components and front-end libraries for future projects.Convert designs and wireframes into high-quality, maintainable code.Optimize components for peak performance across diverse web-capable devices and browsers.Collaborate with fullstack and backend developers as well as UX/UI designers to enhance usability and experience.You’re a Good Fit If You Have:Extensive frontend engineering experience, with strong command of React, JavaScript, and TypeScript.Practical experience with frontend development tools such as Babel, Vite, Webpack, NPM, and Yarn.Familiarity with REST APIs and experience collaborating closely with fullstack and backend developers.

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

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.

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