Software Engineer

Who We Are

We are a well funded, early stage startup led by serial entrepreneurs with over $1B in exits to Salesforce and Microsoft.

Checksum.ai is at the forefront of artificial intelligence, using AI to automate QA software based on real user behavior. Our AI models learn how to use applications and create realistic and durable tests so engineering teams can move fast without breaking your product.

We are looking for a creative, self motivated and results-driven full stack developer who will join the founding team to work on this one of a kind challenge. You’re a builder and a hands-on problem solver. Hooking into a concept and quickly and continuously extracting value is what you do. Your knowledge and experience allow you to stay organized and efficient in a typical dynamic and “noisy” startup environment. You’re a team player and most probably also a leader and mentor. Finally, the thought of joining an early-stage startup makes you feel excited taking into account the responsibility and hard work it entails en route to success.

This is a hybrid role based in our San Francisco office, 4x a week (Monday-Thursday).

Why Join Checksum?

✅ Build AI-driven products from the ground up — own architecture, design, and implementation for systems that automate real-user QA with cutting-edge AI agents.

✅ Impact & ownership — shape engineering culture, influence product direction, and make decisions that directly define the company’s technical DNA.

✅ Work directly with proven founders — collaborate daily with serial entrepreneurs who have scaled and exited companies to Salesforce and Microsoft ($1B+ in combined exits) and our Founders.

✅ Solve deeply technical, one-of-a-kind challenges — create durable, self-learning test systems that push the boundaries of modern full-stack and AI engineering.

Who You Are

• BSc in computer science or equivalent experience


• 5+ years of hands-on/leading fullstack development


• Significant web development experience building software services for SaaS solutions from high-level architecture design to continuous implementation and maintenance


• Strong experience with Python and/or TypeScript/JavaScript


• And at least one modern BE/Fullstack framework experience such as Next.JS or FastAPI


• Strong problem-solving and analytical skills


• Must be available to work in our SF office 4 days a week

Advantages

• Hands on experience building AI Agents


• Experience with implementing software testing automation


• Knowledge of CI/CD and DevOps methodologies

What We Offer

• Opportunity to join a startup at the very first steps but already after substantial funding


• Shape the company’s DNA with us, create impact farther than the engineering scope


• Design the engineering systems from scratch. Choose your tech stack, coding language and architecture


• Work closely with serial entrepreneurs with exists over $1B


• Competitive salary and generous equity