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How to Pass the October Software Engineer Interview in 2026

The October Software Engineer interview runs 5 rounds: Recruiter Screen, Coding Screen, System Design, Onsite Coding, and Behavioral / Leadership. JobMentis holds 12 Software Engineer questions for October, last updated October 23, 2026.

Growth · Software Engineer Interview Guide

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Interview language: English

Expect to code inJavaJavaScriptPython

The October DNA (TL;DR)

October's 'Functional Always' principle underpins the evaluation, seeking candidates who demonstrate a deep understanding of financial product mechanics and can articulate how their work contributes to robust, scalable solutions for October Europe Access. They grade for practical application over theoretical knowledge.

The October Interview Loop

Your onsite loop will typically consist of 5 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 problems, reasoning about defects, 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 October interview outcomes, avoid these common traps:

  • Providing a resolution that ignored the long-term maintainability of the codebase
  • Using incorrect formulas for monthly payment calculation (e.g., APR vs. monthly rate).
  • Overlooking the real-time requirement and proposing batch processing.
  • Failing to mention the specific financial data consistency constraints involved

Test Yourself: October Interview Questions

Three questions from the October bank.

Type · algorithmic

Given a list of loan applications, each with an amount, interest rate, and a submission timestamp, write a function to calculate the total approved loan amount for a given day, considering that applications are approved sequentially and a loan is only approved if its amount is less than or equal to the remaining available capital for that day. Assume a fixed daily capital pool.

Type · past-experience

STAR
Describe a complex bug you encountered in a production system. Walk me through your process of diagnosing and fixing it, and what steps you took to prevent similar issues in the future.

Type · coding

Write a function to simulate loan amortization. Given a principal amount, annual interest rate, and loan term (in years), calculate and return the monthly payment and generate an amortization schedule showing the principal and interest paid each month, and the remaining balance.

+ many more questions, signals, and worked examples

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October Interview Question Bank

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

9 of 12 questions shown

1

Recruiter Screen

1
  1. 1

    Type · motivation

    Why are you interested in joining October, a fintech company focused on SME lending, compared to other opportunities in the tech industry?
2

Coding Screen

2
  1. 2

    Type · algorithmic

    Given a list of loan applications, each with an amount, interest rate, and a submission timestamp, write a function to calculate the total approved loan amount for a given day, considering that applications are approved sequentially and a loan is only approved if its amount is less than or equal to the remaining available capital for that day. Assume a fixed daily capital pool.
  2. 3

    Type · algorithmic

    Implement a function that takes a list of transactions (each with a user ID, amount, and timestamp) and returns the top K users with the highest net transaction volume within a specified time window. Handle potential ties.
3

System Design

3
  1. 4

    Type · design

    CIRCLES
    Design a system to automatically detect and flag potentially fraudulent loan applications in real-time. Consider data sources, processing pipeline, fraud detection models, and alerting mechanisms.
  2. 5

    Type · design

    CIRCLES
    Design a microservice responsible for calculating credit scores for loan applicants. Consider the data inputs, the scoring algorithm's complexity, potential external dependencies (e.g., credit bureaus), and how to ensure low latency and high availability.
  3. + 1 more questions in this round (sign up to unlock)
4

Onsite Coding

3
  1. 6

    Type · algorithmic

    Implement a rate limiter for API requests to prevent abuse. The rate limiter should allow a maximum of N requests per user within a M-minute window. Consider different strategies (e.g., token bucket, leaky bucket) and discuss their trade-offs.
  2. 7

    Type · coding

    Write a function to simulate loan amortization. Given a principal amount, annual interest rate, and loan term (in years), calculate and return the monthly payment and generate an amortization schedule showing the principal and interest paid each month, and the remaining balance.
  3. + 1 more questions in this round (sign up to unlock)
5

Behavioral / Leadership

3
  1. 8

    Type · past-experience

    STAR
    Tell me about a time you had to make a significant technical decision with incomplete information or under pressure. How did you approach it, and what was the outcome?
  2. 9

    Type · past-experience

    STAR
    Describe a complex bug you encountered in a production system. Walk me through your process of diagnosing and fixing it, and what steps you took to prevent similar issues in the future.
  3. + 1 more questions in this round (sign up to unlock)

Unlock all 12 October 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 October

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

October resume and cover letter

Applications to October go through an applicant tracking system, which parses your resume before a recruiter reads it. Keep the layout plain and describe your skills in the words of the posting. The interviews usually run in English, so send your resume and cover letter in English unless the posting asks for another language. Give each point in the October DNA above a bullet that proves it.

Compare October with similar employers

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

Practice October interviews end-to-end

JobMentis for ChromeSee these interview questions on the company's own job postings, on LinkedIn and careers sites.See what it does

Sample answers

What a strong answer to these October interview questions shows.

Given a list of loan applications, each with an amount, interest rate, and a submission timestamp, write a function to calculate the total approved loan amount for a given day, considering that applications are approved sequentially and a loan is only approved if its amount is less than or equal to the remaining available capital for that day. Assume a fixed daily capital pool.

A strong answer shows: Clear and efficient algorithm design.; Correct implementation of the approval logic and capital management.; Consideration of edge cases and input validation..

Describe a complex bug you encountered in a production system. Walk me through your process of diagnosing and fixing it, and what steps you took to prevent similar issues in the future.

A strong answer shows: Detailed explanation of the bug and its impact.; Clear, step-by-step description of the debugging process.; Effective and specific preventative measures implemented.; Understanding of production system stability..

Frequently asked questions

How many interview rounds does October run for Software Engineer candidates?

5 rounds, in this order: Recruiter Screen, Coding Screen, System Design, Onsite Coding, and Behavioral / Leadership.

What does October look for in Software Engineer candidates?

October's 'Functional Always' principle underpins the evaluation, seeking candidates who demonstrate a deep understanding of financial product mechanics and can articulate how their work contributes to robust, scalable solutions for October Europe Access. They grade for practical application over theoretical knowledge.

In which language does October run its interviews?

October usually interviews in English.

How many October Software Engineer interview questions does JobMentis hold?

12 questions across the rounds of the October loop, last updated October 23, 2026.

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