Senior Backend / AI Systems Engineer
Remote - Ontario • FullTime
Posted 5mo ago
About the job
Spellbook is seeking a Senior Backend / AI Systems Engineer to build the backend systems powering its AI copilot for transactional lawyers. This hands-on role requires an engineer who cares about product outcomes, understands scalability, and can transform ambiguity into robust, trustworthy systems. You will be responsible for both traditional software services and AI-driven workflows, working directly within Microsoft Word to enhance contract drafting, review, and negotiation processes.
Responsibilities
- Build and scale backend systems supporting core product functionality.
- Design low-latency, high-reliability search, inference, and orchestration layers for AI features.
- Build and operate RAG retrieval at scale with production-grade performance optimization and permissions-correct data isolation.
- Own core platform concerns for AI, including rate limiting, retries, consistency, fallbacks, and safe degradation.
- Partner with Product and Design to balance latency, accuracy, UX, and reliability.
- Utilize modern development workflows, including agent-assisted coding, to accelerate delivery while maintaining rigorous standards.
- Participate in on-call and incident response, and improve feature reliability.
Requirements
- 5+ years of experience building backend systems in production.
- Strong fundamentals in backend engineering and distributed systems (APIs, data modeling, concurrency, queues, AI inference).
- Strong NoSQL (ideally MongoDB) data modeling and performance tuning skills.
- Ability to take ambiguous, high-impact problems from conception to shipped outcome.
- Strong communication skills, able to explain technical decisions clearly.
- Self-starter and problem-solver motivated by curiosity and continuous improvement.
- Pragmatic understanding of when and where systems need to scale.
- Team player motivated to help the company succeed and improve team workflows.
Benefits
- Company-paid group benefits for you and your family, with $1,000 towards mental health support.
- Generous time off policies and holiday closure.
- Monthly paid meals.
- Annual wellness allowance.
- Parental leave top-ups.
- Competitive stock option grants.