Type · debugging

How to Pass the Terna Software Engineer Interview in 2026
The Terna DNA (TL;DR)
The Terna Interview Loop
Your onsite loop will typically consist of 4 rounds.
- 1
Round 1
Recruiter ScreenMotivation, role fit, logistics. - 2
Round 2
Coding ScreenLeetCode-medium algorithmic problems under time pressure. - 3
Round 3
System DesignDistributed systems, trade-offs at scale, architecture under constraints. - 4
Round 4
Onsite CodingLeetCode-hard, debugging, code clarity, edge cases. - 5
Round 5
Behavioral / LeadershipPast evidence of ownership, influence, resolving conflict.
The Danger Zone: Top Reasons Candidates Fail
Based on our database of Terna interview outcomes, avoid these common traps:
- Giving a generic answer about wanting to work in a large company.
- Focusing on a simple traversal without considering load and capacity.
- Not demonstrating respect for differing opinions or team consensus.
- Over-simplifying the problem by not considering time-series nature of supply and demand.
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Test Yourself: Real Terna Questions
Three real prompts pulled from our database.
Type · system-design
Type · motivation
+ many more questions, signals, and worked examples
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Terna Interview Question Bank
A sample from our database, grouped by round. Sign up to see the full set.
9 of 15 questions shown
Recruiter Screen
1- 1
Type · motivation
Terna is a leader in energy infrastructure. What interests you specifically about contributing to the energy sector, and how do you see your software engineering skills making an impact here?
Coding Screen
3- 2
Type · algorithmic
Imagine Terna needs to optimize the real-time distribution of electricity across a complex grid to minimize losses and prevent overloads. Given a list of grid segments, their current load, and their capacity, design an algorithm to identify the most critical segments that, if overloaded, would cause cascading failures. You can assume a simplified graph representation of the grid. - 3
Type · algorithmic
Terna monitors thousands of energy meters. You receive a stream of meter readings, each with a timestamp and a value. Design a data structure and algorithm to efficiently calculate the average reading for any given 1-hour window in the past 24 hours, with minimal latency. - + 1 more questions in this round (sign up to unlock)
System Design
3- 4
Type · system-design
Design a system for Terna to monitor and predict potential faults in a large network of distributed energy storage units (e.g., batteries). The system should ingest data from thousands of units, detect anomalies, and alert maintenance teams proactively. - 5
Type · system-design
Terna is developing a platform to allow customers to dynamically manage their energy consumption based on real-time pricing and grid load. Design the backend services for this platform, considering aspects like user profiles, device integration, pricing engine, and command execution. - + 1 more questions in this round (sign up to unlock)
Onsite Coding
3- 6
Type · coding
Implement a function that simulates the cascading failure of a power grid. Given a grid represented as an adjacency list and an initial fault point, the function should return the set of nodes that go offline. A node goes offline if its load exceeds its capacity due to upstream failures. Assume each node has a capacity and a current load. - 7
Type · debugging
Here is a piece of code intended to calculate the optimal charging schedule for electric vehicles at a Terna charging station, considering grid load and electricity prices. It's not working as expected. Debug and fix the code. [Provide a code snippet with subtle bugs related to scheduling logic, time zones, or concurrency]. - + 1 more questions in this round (sign up to unlock)
Behavioral / Leadership
5- 8
Type · past-experience
Tell me about a time you had to work with a complex legacy system at Terna. What were the biggest challenges, and how did you approach understanding and improving it? - 9
Type · past-experience
Describe a situation where you disagreed with a technical decision made by your team or lead at Terna. How did you handle the disagreement, and what was the outcome? - + 3 more questions in this round (sign up to unlock)
Unlock all 15 Terna questions, free
No credit card. Every question with its framework, the grading signals interviewers score against, and a worked answer for each.
Interview tracks at Terna
How Terna's DNA translates across functions. Pick your role.
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Practice Terna interviews end-to-end
Terna Mock Interview
Run a live mock interview with our AI interviewer using Terna-style prompts. Get scored on structure, signal, and answer length - exactly how the real loop grades you.
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STAR Stories for Terna Behavioral Rounds
Build a Story Bank of your past wins, mapped to the leadership signals Terna interviewers grade on. Reuse them across every behavioral round.
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Terna Interview Prep Hub
The frameworks behind every Terna round: CIRCLES for product sense, hypothesis-driven debugging for analytical, STAR for behavioral. Learn each one in 10 minutes.
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Interview Frameworks
CIRCLES, STAR, AARRR, RICE, MECE. The exact frameworks that make Terna interviewers nod instead of frown. Step-by-step playbooks with the moves and the pitfalls.
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Sample answers
What a strong answer to these Terna interview questions shows.
Here is a piece of code intended to calculate the optimal charging schedule for electric vehicles at a Terna charging station, considering grid load and electricity prices. It's not working as expected. Debug and fix the code. [Provide a code snippet with subtle bugs related to scheduling logic, time zones, or concurrency].
A strong answer shows: Systematic approach to debugging.; Accurate identification of root causes.; Effective and correct code fixes.; Understanding of the problem domain (scheduling, energy pricing)..
Design a system for Terna to monitor and predict potential faults in a large network of distributed energy storage units (e.g., batteries). The system should ingest data from thousands of units, detect anomalies, and alert maintenance teams proactively.
A strong answer shows: Scalable data ingestion and processing architecture.; Robust anomaly detection mechanisms.; Effective alerting and notification strategy.; Consideration of data storage and retrieval..