Lunar Energy Software Engineer interview questions & guide 2026

Our interview process is designed to evaluate your technical depth, your ability to reason through complex physical systems, and your alignment with the mission of Lunar Energy. Please note that the questions below are representative of patterns we have observed; they are intended to help you understand the type of thinking we value rather than serving as a memorization list.

Technical and Domain Engineering

These questions assess your ability to apply software principles to physical hardware and energy systems. Expect to discuss how software interacts with environmental constraints and hardware schematics.

• Explain the basic concepts involved in a cell reliability study.
• Given a product with Ethernet and WiFi interfaces but no display or buttons, how do you securely connect it to a customer's home network?

Preparation at Lunar Energy requires a blend of fundamental software engineering knowledge and a "first principles" approach to physics and hardware. Do not focus solely on abstract coding problems; instead, practice applying your technical skills to real-world scenarios involving power, heat, and connectivity.

Role-Related Knowledge – You must demonstrate a solid grasp of systems engineering. Interviewers are looking for your ability to connect software logic to physical outcomes, such as thermal management or network security in headless devices.

Problem-Solving Ability – We look for engineers who can structure their thoughts clearly when faced with ambiguous or novel problems. Use the "first principles" method: break down a complex system into its basic components before proposing a solution.

Communication and Collaboration – You will be working in cross-functional teams. Be prepared to explain your technical decisions clearly to both software and hardware engineers. Your ability to articulate the "why" behind your code is just as important as the code itself.

The Lunar Energy interview process is designed to be comprehensive, ensuring that we find candidates who possess both the technical rigor and the collaborative mindset necessary for our mission. While the structure can vary based on the specific team and seniority of the role, you should generally expect a multi-stage process that moves from initial screening to deep-dive technical discussions with engineers and management.

We value efficiency and clarity. While you may encounter different formats—including one-on-one sessions or panel interviews—the focus remains consistent: assessing your ability to solve engineering challenges that impact our products. Candidates who succeed are those who remain engaged, ask insightful questions about our technology, and maintain a professional demeanor throughout every stage.

This timeline provides a high-level view of the progression from initial contact to the final decision. Candidates should use this structure to pace their preparation, ensuring they are ready for both high-level system design conversations and more granular technical screens. Please note that scheduling may be subject to change, so flexibility and proactive communication with your recruiting point of contact are essential.

System Design and Product Thinking

We evaluate your ability to architect solutions that are not only functional but also secure and reliable. You will be expected to think about the end-to-end user experience, especially for headless devices that require robust, "set-it-and-forget-it" connectivity.

Be ready to go over:

• Network security protocols for IoT devices.
• Handling edge cases in offline-to-online transitions.

As a Software Engineer at Lunar Energy, your primary responsibility is the development and maintenance of software that manages energy flow at the edge. You will work closely with hardware engineers to ensure that our software controls are optimized for the physical reality of our battery and inverter systems.

You will participate in the full software development lifecycle, from initial design and prototyping to deployment and monitoring. Collaboration is key; you will frequently interface with product managers to define requirements and with operations teams to ensure that our software performs reliably in the field. Your work will directly influence the scalability and safety of our energy storage products.

A strong candidate for this role possesses a blend of software engineering expertise and a genuine interest in energy systems. We prioritize candidates who can demonstrate deep technical knowledge while remaining adaptable to the unique challenges of the energy sector.

• Must-have skills: Proficiency in low-level or systems-oriented programming (e.g., C, C++, or Rust), understanding of networking protocols (TCP/IP, MQTT, or similar), and experience with embedded systems or IoT architectures.
• Nice-to-have skills: Experience with cloud-to-edge communication, familiarity with energy storage or power electronics, and a background in building reliable, distributed systems.
• Experience level: We look for engineers who have demonstrated success in shipping products that involve both software and hardware components. Your ability to troubleshoot complex, real-world systems is highly valued.

Q: How long does the interview process typically take? A: While it can vary, the process generally spans several weeks. We aim to keep the process moving efficiently, though rigorous technical assessment naturally requires multiple touchpoints.

Q: What is the best way to prepare for the technical rounds? A: Focus on your fundamentals. Be ready to discuss your past projects in detail, specifically focusing on the technical trade-offs you made. Reviewing basic physics and hardware-software interaction principles will also serve you well.

Q: How can I stand out during the interview? A: Successful candidates demonstrate a high degree of curiosity and a "first principles" approach to problem-solving. Showing that you understand the "why" behind your technical decisions is more impressive than simply knowing the "how."

Q: Is this a remote role? A: Work expectations can vary by team and location. We encourage you to discuss specific location or hybrid working preferences directly with your recruiter early in the process.

• Structure your answers: When answering open-ended technical questions, use a clear framework. State your assumptions, outline your approach, and then dive into the details.
• Own your experience: Be prepared to speak deeply about any project listed on your resume. If you haven't worked on hardware before, focus on your ability to learn and apply new technical domains quickly.
• Ask meaningful questions: Use your time with the team to learn about the current engineering challenges. Asking about our product roadmap or how we handle technical debt shows you are thinking like an owner.

The Software Engineer role at Lunar Energy is an opportunity to build technology that fundamentally changes how we power our lives. By focusing on your core engineering fundamentals, your ability to reason through complex physical systems, and your capacity to collaborate across disciplines, you can position yourself as a top candidate.

We encourage you to approach your interviews with confidence and a focus on clarity. Remember that we are looking for engineers who are eager to solve hard problems and contribute to our mission. You can explore additional interview insights, practice questions, and preparation resources on Dataford to ensure you are fully prepared for your conversations with our team.

This module provides insight into compensation structures for this role. Use this data to understand the competitive landscape and to prepare for discussions regarding total compensation, including base salary, equity, and benefits.