Backend Software Engineer

About Reacher Reacher is a YC backed AI SaaS platform building the operating system for TikTok Shop brands and creators. We’re backed by Y Combinator, Pioneer Fund, Rebel Fund, and operators including Steve Huffman (CEO of Reddit), Matteo Franceschetti (CEO of Eight Sleep), Theo Browne ( t3.gg ), Kulveer Taggar (Zeus Living), and Jake Mintz (Bump). We have years of runway and are scaling fast with some of the biggest brands in the world (UnderArmour, Hanes, Logitech, Goli) Our vision is to become the Hubspot for creator marketing, powering brands and creators to connect and grow across all commerce platforms (Youtube Shopping, Instagram Shopping, Shopify, Amazon). We're building key infrastructure for the creator economy and implementing AI with the world's largest brands and creators. Your work will directly impact users on day 1 - our user base depends on our product daily. We build with AI, not around it. Our engineering team uses Claude Code and agentic coding tools as our primary development environment. If you're spending your days directing AI agents to ship code while you focus on architecture, review, and system design — and you can't imagine working any other way — keep reading. What You'll Do Own and lead product features end-to-end : research, design, implement, test, and ship Lead and shape engineering architecture - set standards for code quality, testing, and development practices across the stack Mentor and guide other engineers in adopting AI-native workflows, establishing best practices and patterns Talk directly to customers and translate vague requirements into polished user experiences Design scalable backend systems (Python, FastAPI, PostgreSQL, GCP) Write clean, maintainable, and testable code with minimal oversight Drive architectural decisions and engineering processes that maximize AI-assisted development velocity Ship fast and learn fast - high urgency environment You're a Fit If Engineering Foundations: 2–6 years of professional full-stack experience at a product-first company or FAANG-level environment (Senior SDE ownership expected) Comfortable building features across the entire backend stack Care deeply about product, design, and user experience —not just code Have owned something meaningful end-to-end (a product module, infrastructure refactor, major feature launch) Can set standards for engineering quality and architectural decisions in an AI-native environment Resourceful and thrive in ambiguous environments —you figure things out independently Have strong product intuition and can push back on requirements when needed to improve outcomes AI-Native Development: AI coding experience is your most important and necessary skill - you have deep understanding of modern coding tools, specifically Claude Code, and are proficient with its various modes (Interactive, Plan, Headless, Agent Teams, Delegate) You're "AI-pilled" when it comes to problem-solving - you tackle any new problem, skill, or architectural challenge by leveraging AI tools and an AI-driven workflow. This is your default approach, not an experiment Strong systems thinking and architectural awareness - you direct AI to build while you architect, review, and verify. You know when AI output is correct and when it needs correction Can demonstrate recent AI-native work - you've shipped meaningful projects in the last 90 days where AI coding tools were your primary development environment Technical Skills We Value AI and Agentic Development: Claude Code proficiency: understanding of modes, context engineering ( CLAUDE.md ), custom commands, MCP integrations, and subagent coordination AI-driven development workflows and effective prompt engineering Ability to decompose complex engineering work into tasks suitable for AI assistance Strong judgment for when to leverage AI vs. when to code directly Experience verifying and reviewing AI-generated code for correctness, security, and maintainability Backend: Python, FastAPI, PostgreSQL System design and scalable architecture GCP/cloud infrastructure API design (REST/GraphQL) General: Code reviews, documentation, and establishing conventions Product analytics tools (Amplitude, Mixpanel) for data-driven development Bonus Points If Experience building autonomous agents with the Claude Agent SDK or similar agentic frameworks—you understand multi-agent orchestration, MCP integrations, and production agent deployment Experience with AI image/video generation or manipulation - familiarity with tools like Midjourney, Runway, Stable Diffusion, Sora, or integrating generation APIs into product workflows You've built responsive, delightful UIs (React, TypeScript, Tailwind, shadcn/ui) You've worked at an early-stage startup or been a first/early engineering hire You've built internal tooling, dashboards, or systems that scaled to thousands of users You've led technical initiatives or mentored junior engineers You've built or maintained design systems You're curious about AI, e-commerce, or automation—we work in that space You've shipped side projects or contributed to open-source You've worked directly with designers and can contribute to design discussions Why Join Us Post-revenue company solving real problems for real customers Be a technical leader —define our engineering culture and standards as we scale High autonomy and visibility —no boring tickets Your code reaches users within days, not months Strong engineering-first culture that embraces cutting-edge AI tools Shape both the product and the company When Applying Please send a short note about a complex problem you solved or a new skill you mastered specifically using an AI-driven workflow . GitHub/LinkedIn/resume is great, but we care more about how you think, build, and leverage AI. If you have examples of projects where AI coding tools were central to your workflow in the last 90 days, we'd love to see them.