Senior Backend Engineer

About the Company

Beff is a global Technology partner for Battery Development, mass production, and Data Management.

Job Description

We’re building a high-impact SaaS platform at the intersection of Battery Design, Development, and Production and software, focused on solving real-world problems in the battery ecosystem. We’re looking for a Senior Backend Engineer to take ownership of our backend systems -from architecture to production. You’ll work on systems that ingest, process, and serve complex data, and help shape a platform that customers rely on for critical decision-making. This is a high-ownership, hands-on role for someone who thrives in ambiguity, makes strong technical decisions, and ships reliable systems quickly without sacrificing quality. Experience in the battery sector and practical AI integration is a strong plus.

Job Responsibilities

• Design and build scalable, resilient backend systems using Node.js (NestJS) and Python (FastAPI).
• Own API design and service architecture, balancing performance, maintainability, and developer experience
• Develop and evolve data models and pipelines for complex, real-world datasets (including battery-related data)
• Build and maintain multi-service, cloud-native systems on AWS
• Improve system observability, reliability, and incident response practices
• Drive CI/CD, infrastructure-as-code (Terraform), and secure deployment workflows
• Collaborate closely with product and frontend teams to deliver end-to-end features
• Make pragmatic decisions - knowing when to move fast and when to invest in long-term architecture
• Contribute to a culture of high-quality engineering through code reviews, testing, and continuous improvement

What We’re Looking For

Core Requirements

• 5+ years of experience building and operating production backend systems
• Strong proficiency in Node.js and/or Python (experience with NestJS or FastAPI is a big plus)
• Deep understanding of:
  • API design (REST, service boundaries, versioning)
  • Distributed systems and microservices tradeoffs
  • Data modeling and database performance
• Proven experience building SaaS platforms or complex backend systems
• Hands-on experience with:
  • AWS (or similar cloud platforms)
  • Docker and containerized environments
  • CI/CD pipelines and infrastructure-as-code
• Strong experience with PostgreSQL and/or NoSQL databases
• Ability to debug and resolve complex production issues
• Comfortable working in a fast-moving, startup environment

Strong Plus

• Experience in the battery domain
• Experience building data-intensive or real-time systems
• Exposure to AI/ML systems, LLM integrations, or AI-powered features
• Experience designing event-driven architectures
• Proven experience in team management and driving technical best practices across backend teams.

Tech Stack

• Backend: Node.js (NestJS), Python (FastAPI)
• Frontend: React.js (Hooks, Context, modern state management, component libraries)
• Databases: PostgreSQL, Redis, NoSQL
• Infrastructure: AWS, Docker, Terraform, GitHub Actions

Why Join Us?

• Work on real-world energy problems with tangible impact
• Own systems end-to-end
• Influence architecture, product, and technical direction
• Build from first principles in a fast, execution-focused team
• High autonomy, low bureaucracy, and meaningful responsibility

Salary

Negotiable

Application Process

Please send your resume and CV with the subject "Senior Backend Engineer" to info@b-eff.com.

Join our team at Beff, where we’re not just planning for the future, we’re creating it!