Apollo.io is the leading go-to-market solution for revenue teams, trusted by over 500,000 companies and millions of users globally, from rapidly growing startups to some of the worlds largest enterprises. Founded in 2015, the company is one of the fastest growing companies in SaaS, raising approximately $250 million to date and valued at $1.6 billion. Apollo.io provides sales and marketing teams with easy access to verified contact data for over 210 million B2B contacts and 35 million companies worldwide, along with tools to engage and convert these contacts in one unified platform. By helping revenue professionals find the most accurate contact information and automating the outreach process, Apollo.io turns prospects into customers. Apollo raised a series D in 2023 and is backed by top-tier investors, including Sequoia Capital, Bain Capital Ventures, and more, and counts the former President and COO of Hubspot, JD Sherman, among its board members. YOUR ROLE & MISSION As a Backend Software Engineer, you will be a critical part of our growing company, working on a cross-functional team to implement best practices in technology, architecture, and process. Youll have the chance to work in an open and collaborative environment, receive and give hands-on mentorship and have opportunities to grow and accelerate your career. You love both learning and teaching. In this role, you will be interfacing with design, front-end, analytics, as well as teams outside of Engineering. You enjoy working cross functionally to solve hard problems and make an impact. At Apollo, you strive for quality, and are obsessed with improving quality, automation, and squashing any bugs that sneak through. You have a drive to constantly investigate performance improvements and innovative ideas. Our tech stack is React/Redux/NodeJS on the front end, Ruby/Ruby on Rails / MongoDB / Redis / Elasticsearch on the backend, and Kubernetes / Docker / Ansible / Terraform in infrastructure. DAILY ADVENTURES & RESPONSIBILITIES Design and implement highly scalable backend endpoints Gather product requirements and write design docs to satisfy product needs Drive/Lead full lifecycle of software development: product requirements, architecture, solution design, development, quality assurance, and maintenance Mentor others on best practices and effectively share knowledge Ability to effectively communicate development progress to the product lead, engineering manager, and other stakeholders Be comfortable introducing new technologies and new ideas as required Work effectively as part of a large global team Attend and engage in scrum ceremony meetings, team parties, and manager 1:1s Provide feedback to co-workers in written and verbal form and respond to technical and behavioral feedback from managers and peers COMPETENCIES Proactively acts without being told what to do. Able to identify areas of improvement and driving best practices to deliver high quality, performant, and scalable solutions. Develops services that are highly available and scalable with proper monitoring and alerting in place. Able to up-level the team by sharing knowledge and best practices with the engineering team. Able to deal with ambiguity Ownership of projects from start to finish. Just because the project has been deployed doesn t mean it s done. Organized and able to effectively plan and breakdown large projects into smaller tasks that are easier to estimate and deliver. Lets others speak and seek to understand their viewpoints. A creative and innovative problem solver & previous experience working in an agile, startup environment. Confident in owning your role, and bringing creative ideas to the hands of our users QUALIFICATIONS Minimum 2 years of industry experience in backend development, at least 1-2 years in senior positions, developing large-scale applications Experience developing distributed web applications Your code is comprehensible, well-structured, highly performant Experience with database modeling (SQL or NoSQL both OK) Experience with using and designing RESTful services Strong knowledge of computer science fundamentals, including data structures, algorithms, and object-oriented design Proven experience leveraging AI tools to enhance software development processes, including code generation, debugging, and productivity optimization. Candidates should demonstrate fluency in integrating AI-driven solutions into their workflows and a willingness to stay current with emerging AI technologies Must have: Communication Skills, Problem Solving, Proactivity, Team Player, Listening Skills, Creativity and Innovation, Organization and Planning, Dealing with Ambiguity, Ownership of projects from start to finish, Distributed Web Development Nice to have: B.E/B.Tech in Computer Science, Computer Engineering or similar We are AI Native Apollo.io is an AI-native company built on a culture of continuous improvement. We re on the front lines of driving productivity for our customers and we expect the same mindset from our team. If youre energized by finding smarter, faster ways to get things done using AI and automation, youll thrive here. Why You ll Love Working at Apollo At Apollo, we re driven by a shared mission: to help our customers unlock their full revenue potential. That s why we take extreme ownership of our work, move with focus and urgency , and learn voraciously to stay ahead. We invest deeply in your growth, ensuring you have the resources, support, and autonomy to own your role and make a real impact . Collaboration is at our core we re all for one , meaning you ll have a team across departments ready to help you succeed. We encourage bold ideas and courageous action , giving you the freedom to experiment, take smart risks, and drive big wins. If you re looking for a place where your work matters, where you can push boundaries, and where your career can thrive Apollo is the place for you. Learn more here!

Apollo.io is the leading go-to-market solution for revenue teams, trusted by over 500,000 companies and millions of users globally, from rapidly growing startups to some of the worlds largest enterprises. Founded in 2015, the company is one of the fastest growing companies in SaaS, raising approximately $250 million to date and valued at $1.6 billion. Apollo.io provides sales and marketing teams with easy access to verified contact data for over 210 million B2B contacts and 35 million companies worldwide, along with tools to engage and convert these contacts in one unified platform. By helping revenue professionals find the most accurate contact information and automating the outreach process, Apollo.io turns prospects into customers. Apollo raised a series D in 2023 and is backed by top-tier investors, including Sequoia Capital, Bain Capital Ventures, and more, and counts the former President and COO of Hubspot, JD Sherman, among its board members. YOUR ROLE & MISSION As a Senior Backend Engineer, you will be a critical part of our growing company, working on a cross-functional team to implement best practices in technology, architecture, and process. Youll have the chance to work in an open and collaborative environment, receive and give hands-on mentorship and have opportunities to grow and accelerate your career. You love both learning and teaching. In this role, you will be interfacing with design, front-end, analytics, as well as teams outside of Engineering. You enjoy working cross functionally to solve hard problems and make an impact. At Apollo, you strive for quality, and are obsessed with improving quality, automation, and squashing any bugs that sneak through. You have a drive to constantly investigate performance improvements and innovative ideas. Our tech stack is React/Redux/NodeJS on the front end, Ruby/Ruby on Rails / MongoDB / Redis / Elasticsearch on the backend, and Kubernetes / Docker / Ansible / Terraform in infrastructure. DAILY ADVENTURES & RESPONSIBILITIES Design and implement highly scalable backend endpoints Gather product requirements and write design docs to satisfy product needs Drive/Lead full lifecycle of software development: product requirements, architecture, solution design, development, quality assurance, and maintenance Mentor others on best practices and effectively share knowledge Ability to effectively communicate development progress to the product lead, engineering manager, and other stakeholders Be comfortable introducing new technologies and new ideas as required Work effectively as part of a large global team Attend and engage in scrum ceremony meetings, team parties, and manager 1:1s Provide feedback to co-workers in written and verbal form and respond to technical and behavioral feedback from managers and peers COMPETENCIES Proactively acts without being told what to do. Able to identify areas of improvement and driving best practices to deliver high quality, performant, and scalable solutions. Develops services that are highly available and scalable with proper monitoring and alerting in place. Able to up-level the team by sharing knowledge and best practices with the engineering team. Able to deal with ambiguity Ownership of projects from start to finish. Just because the project has been deployed doesn t mean it s done. Organized and able to effectively plan and breakdown large projects into smaller tasks that are easier to estimate and deliver. Lets others speak and seek to understand their viewpoints. A creative and innovative problem solver & previous experience working in an agile, startup environment. Confident in owning your role, and bringing creative ideas to the hands of our users QUALIFICATIONS Minimum 5 years of industry experience in backend development, at least 1-2 years in senior positions, developing large-scale applications Experience developing distributed web applications Your code is comprehensible, well-structured, highly performant Experience with database modeling (SQL or NoSQL both OK) Experience with using and designing RESTful services Strong knowledge of computer science fundamentals, including data structures, algorithms, and object-oriented design Proven experience leveraging AI tools to enhance software development processes, including code generation, debugging, and productivity optimization. Candidates should demonstrate fluency in integrating AI-driven solutions into their workflows and a willingness to stay current with emerging AI technologies Must have: Communication Skills, Problem Solving, Proactivity, Team Player, Listening Skills, Creativity and Innovation, Organization and Planning, Dealing with Ambiguity, Ownership of projects from start to finish, Distributed Web Development Nice to have: BS or MS degree in Computer Science, Computer Engineering or similar, GCP, Kubernetes, Docker, Mongo, Redis, Ruby on Rails, Microservices, Machine Learning We are AI Native Apollo.io is an AI-native company built on a culture of continuous improvement. We re on the front lines of driving productivity for our customers and we expect the same mindset from our team. If youre energized by finding smarter, faster ways to get things done using AI and automation, youll thrive here. Why You ll Love Working at Apollo At Apollo, we re driven by a shared mission: to help our customers unlock their full revenue potential. That s why we take extreme ownership of our work, move with focus and urgency , and learn voraciously to stay ahead. We invest deeply in your growth, ensuring you have the resources, support, and autonomy to own your role and make a real impact . Collaboration is at our core we re all for one , meaning you ll have a team across departments ready to help you succeed. We encourage bold ideas and courageous action , giving you the freedom to experiment, take smart risks, and drive big wins. If you re looking for a place where your work matters, where you can push boundaries, and where your career can thrive Apollo is the place for you. Learn more here!

Apollo.io is the leading go-to-market solution for revenue teams, trusted by over 500,000 companies and millions of users globally, from rapidly growing startups to some of the worlds largest enterprises. Founded in 2015, the company is one of the fastest growing companies in SaaS, raising approximately $250 million to date and valued at $1.6 billion. Apollo.io provides sales and marketing teams with easy access to verified contact data for over 210 million B2B contacts and 35 million companies worldwide, along with tools to engage and convert these contacts in one unified platform. By helping revenue professionals find the most accurate contact information and automating the outreach process, Apollo.io turns prospects into customers. Apollo raised a series D in 2023 and is backed by top-tier investors, including Sequoia Capital, Bain Capital Ventures, and more, and counts the former President and COO of Hubspot, JD Sherman, among its board members. About Apollo Apollo.io is the leading go-to-market platform for revenue teams, trusted by over 500,000 companies and millions of users globally. We provide sales and marketing teams with easy access to verified contact data for over 210 million B2B contacts and 35 million companies plus the tools to engage and convert them all in one place. As an AI-native company , we are redefining how businesses drive pipeline and revenue. Backed by top-tier investors like Sequoia Capital and Bain Capital Ventures, and recently valued at $1.6B, Apollo is one of the fastest-growing SaaS companies in the world. Your Role & Mission We are looking for a Staff Machine Learning Engineer to join our growing Intelligence team. You will lead mission-critical initiatives that power ML-driven user experiences across search, recommendations, content generation, scoring, and more. Your role is to push Apollo forward as an AI-native product , helping us create intelligent, personalized, and highly automated features that scale. You will collaborate closely with engineers, product managers, and data scientists to build machine learning systems that enhance Apollo s ability to guide our users to value and drive the future of our AI platform. Responsibilities: Design, build, evaluate, deploy and iterate on scalable Machine Learning systems Drive end-to-end ML initiatives problem definition, data exploration, modeling, productionization, and monitoring. Understand the Machine Learning stack at Apollo and continuously improve it Lead development of intelligent features powered by LLMs, embeddings, ranking models, and semantic search. Guide platform architecture decisions and contribute to foundational ML infrastructure (e.g., feature stores, MLOps). Work cross-functionally to define AI-first product experiences and rapidly iterate toward user impact. Mentor and uplevel engineers across the org, influencing engineering best practices and technical direction. Champion the use of AI internally to drive engineering and operational efficiency. Required Qualifications: 8+ years of experience building and scaling machine learning systems in production environments. Strong experience with LLMs and embeddings (e.g., fine-tuning, prompt engineering, vector databases). Hands-on experience with Python and modern ML libraries such as PyTorch, TensorFlow, HuggingFace, or Scikit-learn. Experience with cloud infrastructure (e.g., GCP), orchestration (Airflow), and experimentation platforms (e.g., mlflow, Databricks). Excellent collaboration and communication skills can influence across product and engineering teams. Proven impact shipping ML-driven features in B2B SaaS products or enterprise platforms. Preferred Qualifications: Bachelors, Masters, or a PhD in Computer Science, Mathematics, Statistics, or other quantitative fields or related work experience Experience with retrieval-augmented generation (RAG), search infrastructure, or recommendations at scale. Exposure to GTM, marketing tech, or sales enablement domains in a B2B setting. We are AI Native Apollo.io is an AI-native company built on a culture of continuous improvement. We re on the front lines of driving productivity for our customers and we expect the same mindset from our team. If youre energized by finding smarter, faster ways to get things done using AI and automation, youll thrive here. Why You ll Love Working at Apollo At Apollo, we re driven by a shared mission: to help our customers unlock their full revenue potential. That s why we take extreme ownership of our work, move with focus and urgency , and learn voraciously to stay ahead. We invest deeply in your growth, ensuring you have the resources, support, and autonomy to own your role and make a real impact . Collaboration is at our core we re all for one , meaning you ll have a team across departments ready to help you succeed. We encourage bold ideas and courageous action , giving you the freedom to experiment, take smart risks, and drive big wins. If you re looking for a place where your work matters, where you can push boundaries, and where your career can thrive Apollo is the place for you. Learn more here!