Senior Back-End Developer

Description

About Us

Arpeely is bootstrapped and has been profitable since day one. We built one of the most efficient programmatic acquisition engines on the planet: processing billions of ad decisions a day, generating terabytes of live behavioral data, and turning it into margins most SaaS companies would kill for.

At the core of that engine is a team of data scientists and ML engineers running tens of billions of sub-second predictions a day, deciding in milliseconds which impression is worth buying and what it’s worth.

About Ace AI

Now we’re taking everything we’ve learned about how people move through the web and putting it into our most innovative consumer product yet: Ace AI, an AI-native browser already reaching millions of people, built to simplify and improve everyday online life with the help of AI.

This is a rare opportunity: a category that hasn’t meaningfully changed in over a decade, and a profitable company with the data and the acquisition engine to win it on its own terms.

Come build it with us.

What You’ll Do

• Own backend features end-to-end, from technical design to production monitoring.
• Design, build, and scale backend services and APIs, primarily in Python.
• Own core flows such as authentication, subscriptions, and the services behind our AI features.
• Keep production fast and reliable, working closely with product, AI, and data teams.
• Build AI-native: work with Cursor and Claude Code agents every day and help make our codebase agent-friendly.

Requirements

• 5+ years of hands-on backend development, shipping production systems used by real users.
• Strong backend experience in a modern language (e.g., Python, Node.js, Go). Our backend is Python, and we’ll help you switch.
• Solid understanding of databases, API design, system architecture, and cloud environments.
• Experience running high-traffic systems: performance, monitoring, and production debugging.
• AI-native developer: Cursor and Claude Code are your main way of building every day, including delegating to agents, running them in parallel, and reviewing their output critically.
• B.Sc. in Computer Science or equivalent experience.

Nice to Have

• Python backend experience.
• Experience with GCP, Kubernetes, and Postgres.
• Experience building services around LLMs or AI agents.