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Enterprise · Software Engineer Interview Guide

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Interview language: English

How to Pass the Terna Software Engineer Interview in 2026

The Terna DNA (TL;DR)

Terna's 'Driving Energy' strategic plan emphasizes candidates' capacity to innovate within grid modernization and sustainability, aligning with values like 'Integrity' and 'Meritocracy.' The interview loop seeks individuals who can articulate their contribution to complex infrastructure projects, demonstrating a forward-thinking approach to energy transition challenges.

The Terna Interview Loop

Your onsite loop will typically consist of 4 rounds.

  1. 1

    Round 1

    Recruiter Screen
    Motivation, role fit, logistics.
  2. 2

    Round 2

    Coding Screen
    LeetCode-medium algorithmic problems under time pressure.
  3. 3

    Round 3

    System Design
    Distributed systems, trade-offs at scale, architecture under constraints.
  4. 4

    Round 4

    Onsite Coding
    LeetCode-hard, debugging, code clarity, edge cases.
  5. 5

    Round 5

    Behavioral / Leadership
    Past 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 · 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].

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.

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?

+ 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

1

Recruiter Screen

1
  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?
2

Coding Screen

3
  1. 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.
  2. 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.
  3. + 1 more questions in this round (sign up to unlock)
3

System Design

3
  1. 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.
  2. 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.
  3. + 1 more questions in this round (sign up to unlock)
4

Onsite Coding

3
  1. 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.
  2. 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].
  3. + 1 more questions in this round (sign up to unlock)
5

Behavioral / Leadership

5
  1. 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?
  2. 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. + 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.

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Interview tracks at Terna

How Terna's DNA translates across functions. Pick your role.

Compare Terna with similar employers

Same DNA, different bar. Browse the closest companies in our database and see how their loops differ.

Practice Terna interviews end-to-end

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..

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