Senior AI Engineer

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 world's 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.io'>Apollo.ioApollo.io'>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 world's 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'>Apollo.io provides an end-to-end go-to-market platform that enables sales and marketing teams to source prospects from our database of 210 million B2B contacts and 35 million companies, execute personalized email outreach campaigns, automate booking flows, and manage deals—all within one unified platform. 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. We are AI NativeApollo.io'>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 you're energized by finding smarter, faster ways to get things done using AI and automation, you'll thrive here. Your Role MissionAs a Senior AI Engineer on our AI Engineering team, you will be responsible for building and productionizing advanced AI systems powered by Large Language Models (LLMs) and intelligent agents. You'll work on critical Apollo capabilities including our AI Assistant, Autonomous AI Agents, Deep Research Agents, Conversational Assistant, Semantic Search, Search Personalization, and AI Power Automation features that directly impact millions of users' productivity. The mission of our AI teams is to leverage Apollo's massive scale data and cutting-edge AI to understand and predict user behaviors, personalize experiences, and optimize every stage of the customer journey through intelligent automation. What You'll Be Working OnAI Assistant Agent SystemsAgent Architecture Implementation: Build sophisticated multi-agent systems that can reason, plan, and execute complex sales workflowsContext Management: Develop systems that maintain conversational context across complex multi-turn interactionsLLM and Agentic Platforms: Build scalable large language model and agentic platforms that enable widespread adoption and viability of agent development within the Apollo ecosystemBackend Systems: Build back-end systems necessary to support the agents. AI features: Conversational AI, Natural Language Search, Personalized Email Generation and similar AI featuresClassical AI/ML (Optional Focus)Search Scoring Ranking: Develop and improve recommendation systems and search relevance algorithmsEntity Extraction: Build models for automatic company keywords, people keywords, and industry classificationLookalike Recommendation Systems: Create intelligent matching and suggestion enginesKey ResponsibilitiesDesign and Deploy Production LLM Systems: Build scalable, reliable AI systems that serve millions of users with high availability and performance requirementsAgent Development: Create sophisticated AI agents that can chain multiple LLM calls, integrate with external APIs, and maintain state across complex workflowsPrompt Engineering Excellence: Develop and optimize prompting strategies, understand trade-offs between prompt engineering vs fine-tuning, and implement advanced prompting techniquesSystem Integration: Build robust APIs and integrate AI capabilities with existing Apollo infrastructure and external servicesEvaluation Quality Assurance: Implement comprehensive evaluation frameworks, A/B testing, and monitoring systems to ensure AI systems meet accuracy, safety, and reliability standardsPerformance Optimization: Optimize for cost, latency, and scalability across different LLM providers and deployment scenariosCross-functional Collaboration: Work closely with product teams, backend engineers, and stakeholders to translate business requirements into technical AI solutionsRequired QualificationsCore AI/LLM Experience (Must-Have)8+ years of software engineering experience with a focus on production systems1.5+ years of hands-on LLM experience (2023-present) building real applications with GPT, Claude, Llama, or other modern LLMsProduction LLM Applications: Demonstrated experience building customer-facing, scalable LLM-powered products with real user usage (not just POCs or internal tools)Agent Development: Experience building multi-step AI agents, LLM chaining, and complex workflow automationPrompt Engineering Expertise: Deep understanding of prompting strategies, few-shot learning, chain-of-thought reasoning, and prompt optimization techniquesTechnical Engineering SkillsPython Proficiency: Expert-level Python skills for production AI systemsBackend Engineering: Strong experience building scalable backend systems, APIs, and distributed architecturesLangChain or Similar Frameworks: Experience with LangChain, LlamaIndex, or other LLM application frameworksAPI Integration: Proven ability to integrate multiple APIs and services to create advanced AI capabilitiesProduction Deployment: Experience deploying and managing AI models in cloud environments (AWS, GCP, Azure)Quality Evaluation FocusTesting Evaluation: Experience implementing rigorous evaluation frameworks for LLM systems including accuracy, safety, and performance metricsA/B Testing: Understanding of experimental design for AI system optimizationMonitoring Reliability: Experience with production monitoring, alerting, and debugging complex AI systemsData Pipeline Management: Experience building and maintaining scalable data pipelines that power AI systemsWhat Makes a Great CandidateProduction-First MindsetYou've built AI systems that real users depend on, not just demos or research projectsYou understand the difference between a working prototype and a production-ready systemYou have experience with user feedback, iterative improvements, and feedback systemsTechnical Depth with Business ImpactYou can design end-to-end systems, including back-end systems, asynchronous workflows, LLMs, and agentic systemsYou understand the cost-benefit trade-offs of different AI approachesYou've made decisions about when to use different LLM providers, fine-tuning vs prompting, and architecture choicesEvaluation Quality ExcellenceYou implement repeatable, quantifiable evaluation methodologiesYou track performance across iterations and can explain what makes systems successfulYou prioritize safety, reliability, and user experience alongside capabilityAdaptability LearningYou stay current with the rapidly evolving LLM landscapeYou can quickly adapt to new models, frameworks, and techniquesYou're comfortable working in ambiguous problem spaces and breaking down complex challengesWorking at ApolloWe are a remote-first inclusive organization focused on operational excellence. Our way of working ensures clear expectations and an environment to do your best work with ample reward. 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. Our AI Impact at ApolloJoin a team that's already making significant impact:Our AI Assistant helps sales teams automate research, scoring, and outreach processesAssisted Prompting Mode allows users to leverage AI power-ups without being prompt engineering expertsOur AI email assistant processes hundreds of thousands of words monthly for Professional plan usersWe help users 'book more meetings in less time by automating research, scoring, outreach, more with embedded AI sales assistants'If you're looking for a place where your AI engineering work directly impacts millions of users, where you can push the boundaries of what's possible with LLMs and agents, and where your career can thrive in the AI-native future—Apollo is the place for you. We are AI NativeApollo.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 you're energized by finding smarter, faster ways to get things done using AI and automation, you'll thrive here. Why You’ll Love Working at ApolloAt 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! Originally posted on Himalayas Apply To this Job