Principal Backend Engineer

The role

The Principal Engineer will take hands-on ownership of critical production systems. They will design, build, and ship high-impact backend systems and LLM-powered systems.

What you will do

• Own mission-critical production systems end-to-end
• Design, build, and ship high-impact backend systems and features
• Architect scalable services and cloud infrastructure
• Identify and resolve complex technical bottlenecks
• Build and operate LLM-powered systems and validation loops
• Design and evolve data architectures
• Modernize and improve complex enterprise systems
• Set and uphold engineering quality standards

Required qualifications

• 12+ years of direct experience with Python as a primary language
• Expertise in API architectures including REST and gRPC
• Working proficiency in Node.js and JavaScript
• Advanced proficiency with cloud infrastructure: GCP required
• Experience in at least one additional platform (AWS or Azure)
• Advanced, production-grade experience with Kubernetes and Terraform
• Proven experience operating highly available production systems
• Strong knowledge of relational and NoSQL databases, including PostgreSQL, MySQL, MongoDB, Cassandra, or DynamoDB
• Familiarity with graph databases (e.g., Neo4j) and vector databases/embedding infrastructure
• Hands-on experience building and operating LLM-powered systems in production
• Full-stack capability, including strong frontend architecture fundamentals
• Deep understanding of large-scale enterprise software systems

Nice to have

• Working knowledge of LangSmith or comparable LLM observability/evaluation tooling
• Familiarity with model providers such as OpenAI or Anthropic

About the company

Blitzy is a Cambridge, MA based AI software development platform. They use an agentic software development platform to autonomously build custom software.