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Growth · Software Engineer Interview Guide

Applies via Ashby

How to Pass the Causaly Software Engineer Interview in 2026

The Causaly DNA (TL;DR)

The final interview stage at Causaly often features a technical deep-dive with a Senior Scientist Top, probing intellectual rigor and ability to navigate complex scientific data within the Causaly Products Use context. Candidates are graded on how they frame hypotheses and evaluate findings, expecting precision and a clear articulation of trade-offs.

The Causaly 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, 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 Causaly interview outcomes, avoid these common traps:

  • Focusing on the disagreement rather than the process of influence.
  • Recalculating the entire rolling average and standard deviation for each new data point.
  • Lack of error handling and monitoring in the pipeline.
  • Focusing only on the technical aspects without addressing the interpersonal dynamics.

Test Yourself: Real Causaly Questions

Three real prompts pulled from our database.

Type · Edge Cases

Write a function that takes a list of drug names and their associated target genes, and returns a dictionary mapping each gene to all drugs targeting it. Consider potential issues like duplicate entries, case sensitivity, and empty lists.

Type · Debugging

Here is a piece of code intended to parse chemical compound identifiers from text. It's producing incorrect results for certain valid inputs. Debug and fix the code, explaining your reasoning.

Type · Past Experience

Tell me about a time you had to influence a stakeholder (e.g., engineer, executive, customer) who had a different opinion or priority than you. How did you approach it, and what was the outcome?

+ many more questions, signals, and worked examples

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Causaly Interview Question Bank

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

9 of 23 questions shown

1

Recruiter Screen

1
  1. 1

    Type · Motivation

    What specifically about Causaly's mission in accelerating drug discovery and development excites you as a software engineer?
2

Coding Screen

3
  1. 2

    Type · Algorithmic

    Given a large dataset of drug-target interactions, design an algorithm to efficiently find all potential off-target effects for a new drug candidate. Assume interactions are represented as a graph where nodes are drugs/targets and edges represent interactions. You can query for neighbors of a node.
  2. 3

    Type · Data Structures

    Implement a data structure that can store and quickly retrieve information about molecular compounds and their associated properties (e.g., chemical formula, molecular weight, known targets). The structure should support efficient searching by compound name and by property range.
  3. + 1 more questions in this round (sign up to unlock)
3

System Design

3
  1. 4

    Type · System Design

    Design a scalable system for indexing and querying a massive knowledge graph of biomedical entities (drugs, genes, diseases, proteins) and their relationships. The system needs to support complex queries like 'find all drugs targeting proteins associated with disease X, which are regulated by gene Y'.
  2. 5

    Type · System Design

    How would you design a real-time notification system for researchers when new relevant publications or clinical trial results matching their saved queries become available? Consider the scale of publications and user subscriptions.
  3. + 1 more questions in this round (sign up to unlock)
4

Onsite Coding

4
  1. 6

    Type · Algorithmic

    Implement a function to find the shortest path between two biological entities (e.g., a drug and a disease) in a large, potentially cyclic, knowledge graph. Handle cases where no path exists and optimize for performance on large graphs.
  2. 7

    Type · Debugging

    Here is a piece of code intended to parse chemical compound identifiers from text. It's producing incorrect results for certain valid inputs. Debug and fix the code, explaining your reasoning.
  3. + 2 more questions in this round (sign up to unlock)
5

Behavioral / Leadership

12
  1. 8

    Type · Past Experience

    Tell me about a time you had to influence a stakeholder (e.g., engineer, executive, customer) who had a different opinion or priority than you. How did you approach it, and what was the outcome?
  2. 9

    Type · Collaboration

    Tell me about a time you worked on a cross-functional team where there were significant disagreements or challenges in collaboration. How did you help the team overcome these obstacles?
  3. + 10 more questions in this round (sign up to unlock)

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Interview tracks at Causaly

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

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