Senior Software Engineer, Fullstack (Builder Studio)

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 Apollo is the AI-powered go-to-market platform that helps revenue teams find, engage, and convert their best customers. We combine a database of more than 210 million contacts and 35 million companies with an agentic end-to-end GTM platform, and more than 500,000 companies rely on us to run their go-to-market motion. We are profitable, growing fast, and rebuilding the product around AI and agents. About Builder Studio Builder Studio is Apollo’s new product for building custom GTM software in plain English. A RevOps lead, GTM engineer, or founder describes the tool they need, and Builder Studio plans it, generates real code, and turns it into a working app they can preview, refine through conversation, publish, and share with their team. Every app is made of four building blocks: Pages for the interface, Databases for structured records, Workflows for visible backend logic and scheduled jobs, and Agents that reason over Apollo context and take action. What makes it different from a generic app builder is that Apollo’s data, enrichment, sequences, deliverability, and CRM sync are native building blocks, not bolted-on third-party integrations. It is one of Apollo’s flagship AI bets. The product is in the hands of early design partners now and is heading toward broad launch, which means the next year is about taking a working product and making it reliable, secure, and loved at scale. Your role and mission You will own major slices of Builder Studio end to end, across the builder experience customers see and the systems that make generated apps actually run. You will work on problems most engineers have never touched: an agent that writes and edits software on a customer’s behalf, a runtime that safely executes that code with the user’s own Apollo permissions, and an interface that makes all of it understandable to someone who has never read a line of code. What you will do Build the core Studio experience: the chat-driven build loop, live preview, canvas, and the publish and share flow, so a non-technical user can go from an idea to a working tool in minutes Shape how the agent turns a natural-language goal into a plan, a set of pages, databases, and workflows, and then safely applies follow-up edits without breaking what already works Design the runtime and workflow layer for generated apps, including triggers, scheduled jobs, retries, logging, and the line between deterministic steps and agentic steps Own delegated identity, permissions, secrets, and isolation so generated apps act with exactly the access the user has, and nothing more Expand “connect once, use anywhere” integrations across Apollo data (contacts, companies, lists) and external systems like Google Sheets, Google Drive, CRMs, and MCP-based connectors Make the relationships between pages, data, workflows, and agents legible in the UI, so customers trust what their app is doing Work directly with design partners and customers, turn their feedback into shipped improvements quickly, and help define what the product becomes Raise the quality bar on a fast-moving 0 to 1 team: set patterns, write the tests and evals that matter, and own reliability, performance, and cost of what you ship How we work: AI-native by default You treat AI-assisted development as a core part of how you work. You use agents to move faster on design, investigation, and implementation, with clear judgment about where to review closely, and you look for ways AI raises the leverage of the whole team. On Builder Studio this is doubly true: you are building an AI that writes software, so your own instincts for where AI-generated code succeeds and fails directly shape the product. What we are looking for 5+ years building and shipping production software, with real depth on both the frontend and backend of the same product Strong TypeScript and React skills, including complex, stateful UIs such as editors, canvases, builders, or real-time collaborative surfaces Solid backend and API design experience, ideally including event-driven or workflow systems where retries, idempotency, and observability matter Hands-on experience building with LLMs in production: agent loops, tool calling, context management, code generation, or evals. You know where models break and how to design around it Comfort making sound security calls on systems that run untrusted or generated code: sandboxing, delegated auth, scoped tokens, and secrets handling A track record of taking an ambiguous 0 to 1 product from rough prototype to something customers rely on, and making the scope-versus-quality calls that requires Product instinct and empathy for non-technical users. You care whether a RevOps lead can understand what their app is doing, not just whether the code is correct Genuine, current fluency with AI-assisted development and a high bar for quality and ownership Nice to have Experience building low-code, no-code, or AI app-builder products, or developer tools Experience with edge or serverless runtimes such as Cloudflare Workers and Durable Objects Experience with Ruby on Rails at scale Background in GTM, sales, or marketing tech, or experience working closely with RevOps teams Our tech stack TypeScript and React on the front end; Ruby on Rails and Node.js on the backend; Cloudflare Workers and Durable Objects for the Builder Studio runtime; Python, MongoDB, and Elasticsearch across the wider platform; Kubernetes, Docker, and Terraform in infrastructure; GCP for cloud. What you will love about Apollo You will help build a brand new product from the ground up at a company with the data, distribution, and customer base to make it matter on day one. You will work with a small, high-bar team, own real scope, and have the AI tooling and budget to work at the top of your leverage. Compensation and benefits The listed Pay Range reflects the annual base salary for this role. This salary range may be inclusive of several career levels at Apollo and will be narrowed during the interview process based on a number of factors, including the candidate’s experience, qualifications, and location. Additional benefits for this role may include: equity; company bonus; paid holidays, flex PTO, and parental leave; employee assistance program and wellbeing benefits; global travel coverage; life and disability insurance; and extended health, dental, and vision benefits. 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 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 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. 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 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 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!