How long does the Octopus Energy interview process take?

Most candidates spend between 4 and 8 weeks from recruiter screen to offer. The onsite loop itself runs in a single day or is split across two half-days, with debrief and offer typically within 5 business days after.

How should I prepare specifically for Octopus Energy?

Focus on three things: (1) the company DNA shown above — what they actually grade for, (2) the rounds in your loop, especially the round most candidates underestimate, and (3) drilling on the question types in this guide using a structured framework like CIRCLES or STAR.

Does this apply to engineering or design roles at Octopus Energy?

The DNA stays the same — what changes is the round mix. SWE candidates face coding screens instead of Product Sense; designers face portfolio reviews and design exercises. The "what they value" and behavioral signals carry across all functions.

What interests you about working in the energy sector, and specifically at Octopus Energy?

Type: motivation. Sign up at JobMentis to see the full framework, grading signals, and worked answer for this question.

Given a stream of smart meter readings (timestamp, energy_consumed), write a function to calculate the peak consumption hour for a given day, handling potential out-of-order or missing readings.

Type: algorithmic. Sign up at JobMentis to see the full framework, grading signals, and worked answer for this question.

Implement a function to determine if a customer's energy usage pattern (represented as a list of hourly consumption values) matches a predefined tariff profile, allowing for a certain tolerance percentage.

Type: algorithmic. Sign up at JobMentis to see the full framework, grading signals, and worked answer for this question.

Design a system to ingest, process, and store real-time smart meter data from millions of households for billing and analytics purposes. Consider data volume, velocity, and variety.

Type: system-design. Sign up at JobMentis to see the full framework, grading signals, and worked answer for this question.

Design an API service that allows customers to view their historical energy consumption data, filter by date range, and download reports. Discuss potential bottlenecks and how to mitigate them.

Type: system-design. Sign up at JobMentis to see the full framework, grading signals, and worked answer for this question.

Write a function to simulate the charging and discharging of a home battery system based on solar generation, grid prices, and user-defined preferences (e.g., prioritize self-consumption, minimize cost).

Type: algorithmic. Sign up at JobMentis to see the full framework, grading signals, and worked answer for this question.

A customer reports that their monthly bill seems incorrect, showing much higher consumption than usual. Here's a snippet of the processed meter data and the billing calculation logic. Find the bug.

Type: debugging. Sign up at JobMentis to see the full framework, grading signals, and worked answer for this question.

Tell me about a time you had a significant disagreement with a colleague or stakeholder. How did you approach the situation, and what was the outcome?

Type: Conflict Resolution. Sign up at JobMentis to see the full framework, grading signals, and worked answer for this question.

Other roles at Octopus Energy:Product Manager Software Engineer Sales Marketing Customer Success

Growth · Software Engineer Interview Guide

How to Pass the Octopus Energy Software Engineer Interview in 2026

The Octopus Energy DNA (TL;DR)

Octopus Energy seeks individuals passionate about green energy, customer advocacy, and collaborative problem-solving. They assess alignment with their "tentacles" (values) like honesty, simplicity, and a drive to make a positive impact, alongside practical skills and adaptability.

The Octopus Energy Interview Loop

Your onsite loop will typically consist of 5 rounds.

1
Round 1
Recruiter Screen
Motivation, role fit, logistics.
2
Round 2
Coding Screen
LeetCode-medium algorithmic problems under time pressure.
3
Round 3
System Design
Distributed systems, trade-offs at scale, architecture under constraints.
4
Round 4
Onsite Coding
LeetCode-hard, debugging, code clarity, edge cases.
5
Round 5
Behavioral / Leadership
Past evidence of ownership, influence, resolving conflict.

The Danger Zone: Top Reasons Candidates Fail

Based on our database of Octopus Energy interview outcomes, avoid these common traps:

Inefficiently iterating through the entire stream for each query instead of maintaining a running state.
Not clearly articulating the steps taken to resolve the conflict.
Designing a monolithic API without thinking about microservices or horizontal scaling.
Not considering memory constraints if the dataset is extremely large.

Test Yourself: Real Octopus Energy Questions

Three real prompts pulled from our database.

Type · Ownership

Tell me about a time you took full ownership of a problem or project that wasn't explicitly assigned to you, and what was the outcome?

Type · behavioral

Describe a time you faced a significant technical challenge or a bug that was difficult to track down. What steps did you take to resolve it, and what did you learn?

Type · Influence

Describe a situation where you had to influence a key stakeholder (internal or external) who was initially resistant to your proposal. How did you approach it, and what was the result?

+ many more questions, signals, and worked examples

Unlock the rubric →

Octopus Energy Interview Question Bank

A sample from our database, grouped by round. Sign up to see the full set.

9 of 21 questions shown

Recruiter Screen

1
Type · motivation
What interests you about working in the energy sector, and specifically at Octopus Energy?

Coding Screen

2
Type · algorithmic
Given a stream of smart meter readings (timestamp, energy_consumed), write a function to calculate the peak consumption hour for a given day, handling potential out-of-order or missing readings.
3
Type · algorithmic
Implement a function to determine if a customer's energy usage pattern (represented as a list of hourly consumption values) matches a predefined tariff profile, allowing for a certain tolerance percentage.
+ 1 more questions in this round (sign up to unlock)

System Design

4
Type · system-design
Design a system to ingest, process, and store real-time smart meter data from millions of households for billing and analytics purposes. Consider data volume, velocity, and variety.
5
Type · system-design
Design an API service that allows customers to view their historical energy consumption data, filter by date range, and download reports. Discuss potential bottlenecks and how to mitigate them.
+ 1 more questions in this round (sign up to unlock)

Onsite Coding

6
Type · algorithmic
Write a function to simulate the charging and discharging of a home battery system based on solar generation, grid prices, and user-defined preferences (e.g., prioritize self-consumption, minimize cost).
7
Type · debugging
A customer reports that their monthly bill seems incorrect, showing much higher consumption than usual. Here's a snippet of the processed meter data and the billing calculation logic. Find the bug.
+ 1 more questions in this round (sign up to unlock)

Behavioral / Leadership

8
Type · Conflict Resolution
Tell me about a time you had a significant disagreement with a colleague or stakeholder. How did you approach the situation, and what was the outcome?
9
Type · Ownership
Tell me about a time you took full ownership of a problem or project that wasn't explicitly assigned to you, and what was the outcome?
+ 9 more questions in this round (sign up to unlock)

Unlock the full Octopus Energy question bank

Free signup, no credit card. You get every question + the framework, grading signals, and worked answer for each.

Unlock all questions →

Interview tracks at Octopus Energy

How Octopus Energy's DNA translates across functions. Pick your role.

SWE candidates are evaluated on technical proficiency, problem-solving skills for scalable energy infrastructure, and clean code practices. Experience with cloud technologies (AWS) and contributing to their Kraken tech stack, ensuring reliability and efficiency, is key.

Ownership

Tell me about a time you took full ownership of a problem or project that wasn't explicitly assigned to you, and what was the outcome?

behavioral

Describe a time you faced a significant technical challenge or a bug that was difficult to track down. What steps did you take to resolve it, and what did you learn?

+ 1 more

Unlock the Software Engineer grading rubric for Octopus Energy

See full Software Engineer guide