A Software Engineer at Cantina plays a pivotal role in driving innovation and delivering high-quality software solutions. This position is essential as it contributes directly to the development of products that enhance user experience and meet business objectives. As a Software Engineer, you will work on complex projects that involve designing, coding, testing, and maintaining software applications. The impact of your work will resonate across various teams and ultimately influence the company’s success in providing value to its customers. The role is particularly interesting due to the diverse range of technologies and methodologies employed at Cantina. You will have the opportunity to collaborate with product managers, designers, and other engineers to create scalable and efficient systems. Whether you are tackling backend infrastructure or developing user-facing applications, your contributions will help shape the future of the company's offerings. Expect a dynamic environment where your skills will be put to the test, and your creativity will be encouraged.
Phone Screen
reportedInitial phone screen conducted by a recruiter to discuss qualifications and role fit.
What to demonstrate
- Initial phone screen conducted by a recruiter to discuss qualifications and role fit
- Depth in Coding Exercises (Algorithmic Coding)
How to prepare
- Be able to walk your CV end to end in two minutes, and say why this company specifically.
- Have your salary expectations, notice period and location constraints ready, and ask for the rest of the loop in writing.
Technical Assessments
reportedIncludes coding challenges to evaluate technical skills.
What to demonstrate
- Includes coding challenges to evaluate technical skills
- Depth in Coding Exercises (Algorithmic Coding)
How to prepare
- Answer aloud and timed: How would you optimize a slow-running SQL query?
- Answer aloud and timed: Describe a situation where you had to debug a complex issue. What was your approach?
Behavioral Interviews
reportedInterviews focused on assessing cultural fit and collaboration skills.
What to demonstrate
- Interviews focused on assessing cultural fit and collaboration skills
- Depth in Coding Exercises (Algorithmic Coding)
How to prepare
- Prepare three examples from your own work, each with a decision you made and an outcome you can quantify.
- Re-read the description of the behavioral interviews above and write down what you would ask to confirm before it.
Meet Team Members
reportedOpportunities to meet various team members and stakeholders for insights.
What to demonstrate
- Opportunities to meet various team members and stakeholders for insights
- Depth in Coding Exercises (Algorithmic Coding)
How to prepare
- Answer aloud and timed: How would you find the longest substring without repeating characters?
- Answer aloud and timed: Implement a binary search algorithm.
PracHub editorial advice for the preparation topics above.
Practice coding problems
Regularly practice coding problems on platforms like LeetCode or HackerRank to build your confidence and improve your problem-solving skills.
Understand system design principles
Familiarize yourself with basic system design concepts as they may come up during interviews, especially for more experienced roles.
Prepare questions
Have thoughtful questions ready for your interviewers that demonstrate your interest in the team and the projects you will be working on.
Showcase your projects
Be prepared to discuss previous projects in detail, highlighting your contributions and the impact of your work.
Choose a category, try a prompt, then open its approach, worked solution or follow-up when you need it.
Can you explain the difference between synchronous and asynchronous programming?
Can you explain the difference between synchronous and asynchronous programming?
Approach
- Say what the runtime actually does before reasoning about the code.
- Name what is shared across threads and what owns each piece of state.
- Identify the window where an invariant is briefly untrue.
- Distinguish a value from a reference to it, and say which one you handed out.
Follow-up
- What happens if two callers reach this at the same time?
- Where could this allocate more than you expect?
Write a function to reverse a linked list.
Write a function to reverse a linked list.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
How would you find the longest substring without repeating characters?
How would you find the longest substring without repeating characters?
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Implement a binary search algorithm.
Implement a binary search algorithm.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Given an array of integers, find two numbers such that they add up to a specific target.
Given an array of integers, find two numbers such that they add up to a specific target.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
Explain how you would approach solving a problem using recursion.
Explain how you would approach solving a problem using recursion.
Approach
- Restate the input: its shape, its size, and what is guaranteed about it.
- Name the brute-force solution and its complexity before improving on it.
- Choose the data structure from the access pattern, not from familiarity.
- State the target complexity and say which constraint rules the naive version out.
Follow-up
- How does this change if the input no longer fits in memory?
- What is the worst case, and how likely is it on real data?
How would you optimize a slow-running SQL query?
How would you optimize a slow-running SQL query?
Approach
- Name the grain you start from and join outward from it.
- Check whether any join is one-to-many before aggregating, or the sums inflate.
- Say which index the query would use, and what makes it unusable.
- Handle the rows that do not match: that is usually the actual question.
Follow-up
- How does the query change if that join becomes one-to-many?
- What happens to this when the table is ten times larger?
Keep soft-deleted accounts from blocking re-registration
app_user holds user_id, tenant_id, email CITEXT, password_hash (NULL for SSO principals), email_verified_at, auth_version, status ('invited','active','suspended','deactivated'), created_at, updated_at, deleted_at. Two live accounts for one address inside a tenant must be impossible, but an address freed by a soft delete must be reusable, and the same tenant may delete and re-register it repeatedly. Write the uniqueness DDL for PostgreSQL 16, then the equivalent for MySQL 8 where partial indexes do not exist, and say what each permits once three deleted rows already hold that address.
Approach
- Start from what is actually unique: not (tenant_id, email), but (tenant_id, email) among live rows. PostgreSQL says that directly — CREATE UNIQUE INDEX app_user_live_email ON app_user (tenant_id, email) WHERE deleted_at IS NULL. A full constraint over the same two columns burns the address permanently the first time someone deletes an account.
- Keep case-insensitivity in the type or the index, never in the application: CITEXT as given, or UNIQUE (tenant_id, lower(email)) as an expression index where the extension is unavailable. A case-sensitive unique column is exactly how two accounts for one human appear.
- For MySQL 8 the predicate has to move inside the key: add a discriminator column that is a constant 0 while the row is live and is set to user_id on delete, with UNIQUE (tenant_id, email, deleted_marker). Live rows share the constant and still collide; deleted rows differ from each other and stop colliding.
- State the NULL variant and its dependency: leaving the marker NULL for deleted rows also works, because a unique index treats NULLs as distinct — true in MySQL, and true in PostgreSQL only under the default NULLS DISTINCT, which PostgreSQL 15 lets you reverse. Check the polarity against the three existing deleted rows: constant-on-live is what preserves the collision you want, and reversing it silently admits duplicate live accounts.
Follow-up
- A deleted account re-registers with the same address the next day. Do the old resource rows follow the new user_id, and how does the API keep the two principals apart?
- How do you honour an erasure request while resource_revision.actor_user_id still references this table?
What are the principles of object-oriented programming?
What are the principles of object-oriented programming?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
A product is experiencing performance issues. How would you diagnose and resolve the problem?
A product is experiencing performance issues. How would you diagnose and resolve the problem?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Imagine you are tasked with designing a new feature for an existing application. What steps would you take?
Imagine you are tasked with designing a new feature for an existing application. What steps would you take?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
How would you approach refactoring a legacy codebase?
How would you approach refactoring a legacy codebase?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
What metrics would you use to evaluate the success of a software project?
What metrics would you use to evaluate the success of a software project?
Approach
- Clarify what is being asked and what a complete answer contains.
- State your assumptions explicitly before working the problem.
- Say what you would check first and why it is the highest-information step.
- Work from the requirement backwards to the design.
Follow-up
- What assumption would you test first?
- How would you know your answer was wrong?
Describe a situation where you had to debug a complex issue. What was your approach?
Describe a situation where you had to debug a complex issue. What was your approach?
Approach
- Establish what changed and when, before forming any theory.
- Pick a bisection that eliminates candidates whichever way it turns out.
- Check the instrumentation before believing the symptom.
- Separate the trigger from the cause; the deploy is rarely the bug.
Follow-up
- What would you look at first, and what would it rule out?
- How would you tell a cause from a coincidence here?
Built from the rounds and topics Cantina candidates report.
Prepare, practise & reflect
One practical outcome each day. Spend longer where you need it.
0 / 7 done01Map the Cantina loop
- Write out the reported sequence: Phone Screen, Technical Assessments, Behavioral Interviews, Meet Team Members.
- For each round, write one sentence on what it is judging, from the description above, and mark the one you are least ready for.
Deliverable: A one-page map of the 4 reported rounds, with the weakest marked.
02Work Coding Exercises (Algorithmic Coding)
- Spend the session on Coding Exercises (Algorithmic Coding), which Cantina candidates report being tested on.
- Write one worked example in Coding Exercises (Algorithmic Coding) and time yourself on it.
Deliverable: One timed worked example in Coding Exercises (Algorithmic Coding).
03Work Problem Solving
- Spend the session on Problem Solving, which Cantina candidates report being tested on.
- Write one worked example in Problem Solving and time yourself on it.
Deliverable: One timed worked example in Problem Solving.
04Work Algorithmic Reasoning
- Spend the session on Algorithmic Reasoning, which Cantina candidates report being tested on.
- Write one worked example in Algorithmic Reasoning and time yourself on it.
Deliverable: One timed worked example in Algorithmic Reasoning.
05Answer out loud: Technical / Domain Questions
- Answer aloud, timed: What are the principles of object-oriented programming?
- Answer aloud, timed: Can you explain the difference between synchronous and asynchronous programming?
Deliverable: Spoken answers to 2 reported Technical / Domain Questions question(s), under time.
06Answer out loud: Coding / Algorithms
- Answer aloud, timed: Write a function to reverse a linked list.
- Answer aloud, timed: How would you find the longest substring without repeating characters?
Deliverable: Spoken answers to 2 reported Coding / Algorithms question(s), under time.
07Answer out loud: Behavioral / Leadership
- Answer aloud, timed: Describe a time you faced a significant challenge at work. How did you overcome it?
- Answer aloud, timed: How do you prioritize tasks when working on multiple projects?
Deliverable: Spoken answers to 2 reported Behavioral / Leadership question(s), under time.
Expand any day for tasks and deliverables. Your progress is saved on this device.
Behavioural rounds judge the decision you made and what it cost.
What is your experience with version control systems?
What is your experience with version control systems?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Describe a time you faced a significant challenge at work. How did you overcome it?
Describe a time you faced a significant challenge at work. How did you overcome it?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you prioritize tasks when working on multiple projects?
How do you prioritize tasks when working on multiple projects?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Can you give an example of how you contributed to a team’s success?
Can you give an example of how you contributed to a team’s success?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
What do you believe is the most important quality for a software engineer to possess?
What do you believe is the most important quality for a software engineer to possess?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
How do you handle constructive criticism?
How do you handle constructive criticism?
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
Discuss a time when you had to pivot your approach due to changing requirements.
Discuss a time when you had to pivot your approach due to changing requirements.
Approach
- Pick a story where you made the decision, not one where you watched it.
- State the situation in two sentences and spend the rest on the reasoning.
- Give the blast radius: what could have broken, and what you measured.
- Name the disagreement and how you resolved it with evidence.
Follow-up
- What would you do differently if you ran that again?
- How did you know your change caused the improvement?
- 01
What is your experience with version control systems?
- 02
Describe a time you faced a significant challenge at work. How did you overcome it?
- 03
How do you prioritize tasks when working on multiple projects?
- 04
Can you give an example of how you contributed to a team’s success?
What is the interview difficulty and how much preparation time is typical?
The interview difficulty for the Software Engineer position at Cantina is generally rated as moderate. Candidates typically spend 2-4 weeks preparing, focusing on coding challenges and technical concepts.
Cantina Software Engineer candidate reports ↗What differentiates successful candidates?
Successful candidates demonstrate a strong technical foundation, effective problem-solving skills, and the ability to communicate clearly. They also align well with Cantina’s values and culture.
Cantina Software Engineer candidate reports ↗Can you describe the culture and working style at Cantina?
Cantina fosters a collaborative and innovative culture where engineers are encouraged to share ideas and work as part of a team. You will find an emphasis on continuous learning and improvement.
Cantina Software Engineer candidate reports ↗What is the typical timeline from initial screen to offer?
The timeline can vary, but candidates generally receive feedback within two weeks after their final interview. The entire process, from initial contact to offer, typically takes 4-6 weeks.
Cantina Software Engineer candidate reports ↗Are there remote work or hybrid expectations?
While many roles at Cantina offer flexibility in location, specific remote or hybrid policies may vary by team and project. Be sure to clarify expectations during your interview.
Cantina Software Engineer candidate reports ↗What topics does Cantina test in interviews?
Cantina interviews most often cover Coding Exercises (Algorithmic Coding), Problem Solving, Algorithmic Reasoning, Code Review Practices, and Programming Competency (Language-Agnostic). The exact emphasis depends on the specific role you apply for.
Cantina Software Engineer candidate reports ↗Sources & methodology 3 sources ↗
No official company page is cited. Rounds and questions come from candidate reports and PracHub editorial material; each source shows the date it was read.
- 01Cantina Software Engineer candidate reports ↗
Company-reported rounds, questions and FAQ.
Candidate reports · Accessed 2026-09-22 - 02PracHub Software Engineer practice ↗
PracHub practice material, not company-reported.
PracHub page · Accessed 2026-09-22 - 03PracHub preparation framework ↗
PracHub preparation guidance.
PracHub page · Accessed 2026-09-22
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