Criteo interview, decoded.
Criteo's engineering loop, as candidates and one employee describe it, runs an HR call, two interviews with two or three LeetCode-style questions at easy to medium level, a system design round and a culture-fit round. The coding is pair programming in a shared HackerRank pad over video, in the language you choose. Two problems keep coming back: filling or recolouring adjacent pixels in a grid, which candidates call flood fill, and a sliding-window problem where you start with the O(n²) answer and improve it to O(n). The design prompt most often reported is an online chess game.
Criteo was founded in Paris and had 3,543 employees at the end of June 2026. It moved its legal home from France to Luxembourg in July 2026, and its board has approved a further move to the United States, expected in January 2027. In March 2026 it became OpenAI's first advertising technology partner. Criteo says it doesn't want AI answering interview questions for you, and one employee described a return to the office that starts at one day a week and is planned to reach three.
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The questions for your exact Criteo role and level.
Interviewing at Criteo? Below are the questions candidates report. For the ones your exact role and level will get, paste the posting. Your first mock is free.
Who Criteo hires
The roles and the backgroundCriteo hires software engineers, machine learning engineers and researchers, SRE and data engineers, in offices that include Paris, Grenoble and Bucharest. The interviews candidates describe run in English. Criteo's own hiring page lists six steps, says there is no one-size-fits-all process, and promises that your recruiter will tell you what to prepare for the technical step. A candidate in July 2026 asked whether Paris is still growing, as Criteo has been hiring more in Romania.
What is the Criteo interview process?
Round by roundCriteo publishes a generic outline: application, a recruiter call, interviews, a technical interview, a final interview and a decision. The rounds below come from candidate accounts on Reddit between 2024 and 2026, including an employee's description of the loop in December 2025.
Your background, skills and goals. Criteo says a second call with the hiring manager can be scheduled straight away.
One candidate in September 2025 was sent this before the interviews. Ask your recruiter whether your role has it and what it covers.
Two or three easy to medium LeetCode-style problems in total, in your language of choice. Reported: flood fill, a hash map search, a ransom note check and a sliding window improved from O(n²) to O(n).
Most often an online chess game: one player creates a game and invites another by link, with questions on SQL or NoSQL, caching, and HTTP against WebSockets. Candidates say this round sets your level.
Your goals and how you work. Two candidates report being rejected here after strong technical rounds, one for what they called two petty reasons.
What Criteo screens for
What every round is really testingCriteo's hiring page says it hires personalities as well as skills, and its advice on AI says what it wants to hear from you.
- Your own perspective and experience, which Criteo says AI can't provide
- Explaining your thinking and how you made decisions
- Curiosity and good questions
- Improving a working solution: brute force first, then the better complexity
- Design judgement, which candidates say decides the level of the offer
Criteo interview questions
Candidate-reported themesThe technical themes are the ones candidates report from 2024 to 2026. The behavioural questions follow what Criteo says it looks for.
Behavioural & motivation
- Tell me about a decision you made on a project and how you reached it.
- Describe a time you changed your mind after someone challenged your approach.
- What impact have you had in your current role, in numbers if you can?
- Why Criteo?
Technical
- Grid traversal: Flood fill: recolour or change cells depending on their neighbours, with follow-ups on threads
- Hash maps and strings: An array search with a hash map, and the ransom note problem
- Improving complexity: A sliding-window problem: give the O(n²) answer, then bring it to O(n)
- Real-time system design: Online chess: game creation, invitation links, SQL or NoSQL, caching, HTTP or WebSockets
- ML system design: For ML roles: ML system design and machine learning theory
These are the reported themes — your loop is role-specific. Paste the actual posting and Calibrd predicts the questions for that exact role and level.
Predict my Criteo questions →Criteo coding and system design: reported questions and answers
Reported problems and how to solve themCriteo's coding rounds are pair programming on a HackerRank pad inside a video call, in the language you choose. Candidates since 2024 describe patient interviewers who help if you are stuck, and the same few problems. The design round is where candidates say the level is decided: one candidate was offered a lower level after a weaker design interview.
- Flood fill (pixel colouring): Treat the grid as a graph and visit neighbours with BFS or DFS, marking what you have seen. State the complexity, then be ready for the follow-up on threads: how you would split the grid or protect shared state.
- Sliding window, from O(n²) to O(n): Give the brute force first, as the interviewers ask, then keep a running window with two pointers so each element enters and leaves once. Two candidates say this improvement is where they fell short.
- Ransom note and hash map search: Count characters or values in a hash map in one pass, then check the other side against the counts. Say why the lookup is constant time.
- Design an online chess game: Start with the flow: create a game, share an invite link, the second player joins, moves go back and forth. Then choose storage (game state and history), explain caching, and argue for WebSockets for live moves, with HTTP for everything else.
Criteo's advice on AI: use it to prepare and practise, never to answer interview questions for you. In the design round, explain each decision out loud.
Pay
What the offer looks likeTotals a year for Criteo software engineers in France on Levels.fyi, read on 26 September 2026 from 217 submissions. The page's range is €57.9K to €150K+; the levels are shown as monthly amounts in US dollars, so these are converted at the page's own rate and rounded, and should be treated as estimates. Candidates report a junior base of €52K to €55K with an 11% bonus (August 2025), and an offer of €57K fixed with a 10% bonus and €19K of stock over four years (March 2025). Criteo's ads carry no pay range. Calibrd benchmarks the offer against your level and location in the report.
How to prepare for a Criteo interview
In order- Practise grid problems until flood fill is automatic, then prepare the threading follow-up.
- For every problem, say the brute force, then improve it. Candidates fail on the step from O(n²) to O(n).
- Rehearse the online chess design end to end: invite link, game state, storage, caching, WebSockets.
- Prepare the behavioural round as seriously as the coding. Two candidates were rejected there after strong technical rounds.
- Ask which level you are being interviewed for. Candidates say the design round decides it.
- Use AI to prepare only. Criteo says you must not let AI answer interview questions for you.
- Ask about the office rule and the team's location. Criteo is moving its legal home to the US and hiring in Bucharest.
This guide covers Criteo's engineering hiring. Criteo publishes a generic outline and its AI rules; the rounds and problems come from candidate accounts on Reddit between 2024 and 2026, and the company facts from its own results and press releases. For management and leadership roles the loop is similar but the bar shifts to people, delivery and strategy, so pair it with the leadership interview prep hub. The bar for your exact role comes from the role-by-role guides, and the prep that actually transfers is spoken, so run a mock interview before the real one.
Knowing the questions isn’t the same as answering them out loud. Run a Criteo mock: spoken answers, coached on the spot. Your first mock is free.
Run a Criteo mock →FAQ & sources
The short answersWhat is Criteo's interview process?
Criteo publishes a generic outline: application, a recruiter call, interviews, a technical interview, a final interview and a decision. The rounds below come from candidate accounts on Reddit between 2024 and 2026, including an employee's description of the loop in December 2025. Recruiter call: Your background, skills and goals. Criteo says a second call with the hiring manager can be scheduled straight away. Online assessment: One candidate in September 2025 was sent this before the interviews. Ask your recruiter whether your role has it and what it covers. Pair programming: Two or three easy to medium LeetCode-style problems in total, in your language of choice. Reported: flood fill, a hash map search, a ransom note check and a sliding window improved from O(n²) to O(n). System design: Most often an online chess game: one player creates a game and invites another by link, with questions on SQL or NoSQL, caching, and HTTP against WebSockets. Candidates say this round sets your level. Behavioural and final interview: Your goals and how you work. Two candidates report being rejected here after strong technical rounds, one for what they called two petty reasons.
What does Criteo look for in candidates?
Criteo's hiring page says it hires personalities as well as skills, and its advice on AI says what it wants to hear from you. Your own perspective and experience, which Criteo says AI can't provide Explaining your thinking and how you made decisions Curiosity and good questions Improving a working solution: brute force first, then the better complexity Design judgement, which candidates say decides the level of the offer
What questions does Criteo ask in interviews?
The technical themes are the ones candidates report from 2024 to 2026. The behavioural questions follow what Criteo says it looks for. Tell me about a decision you made on a project and how you reached it. Describe a time you changed your mind after someone challenged your approach. What impact have you had in your current role, in numbers if you can? Why Criteo? Grid traversal Hash maps and strings Improving complexity Real-time system design ML system design
What does Criteo ask in the coding and system design interviews?
Criteo's coding rounds are pair programming on a HackerRank pad inside a video call, in the language you choose. Candidates since 2024 describe patient interviewers who help if you are stuck, and the same few problems. The design round is where candidates say the level is decided: one candidate was offered a lower level after a weaker design interview. Flood fill (pixel colouring): Treat the grid as a graph and visit neighbours with BFS or DFS, marking what you have seen. State the complexity, then be ready for the follow-up on threads: how you would split the grid or protect shared state. Sliding window, from O(n²) to O(n): Give the brute force first, as the interviewers ask, then keep a running window with two pointers so each element enters and leaves once. Two candidates say this improvement is where they fell short. Ransom note and hash map search: Count characters or values in a hash map in one pass, then check the other side against the counts. Say why the lookup is constant time. Design an online chess game: Start with the flow: create a game, share an invite link, the second player joins, moves go back and forth. Then choose storage (game state and history), explain caching, and argue for WebSockets for live moves, with HTTP for everything else.
How do I prepare for a Criteo interview?
Practise grid problems until flood fill is automatic, then prepare the threading follow-up. For every problem, say the brute force, then improve it. Candidates fail on the step from O(n²) to O(n). Rehearse the online chess design end to end: invite link, game state, storage, caching, WebSockets. Prepare the behavioural round as seriously as the coding. Two candidates were rejected there after strong technical rounds. Ask which level you are being interviewed for. Candidates say the design round decides it. Use AI to prepare only. Criteo says you must not let AI answer interview questions for you. Ask about the office rule and the team's location. Criteo is moving its legal home to the US and hiring in Bucharest.
- 01Criteo, how we hirethe six steps, no one-size-fits-all process, a possible second call with the hiring manager, and the recruiter sharing what to prepare
- 02Criteo, using AI in your interview journeyuse AI to learn, prepare and practise; do not let AI answer interview questions for you
- 03Criteo, second quarter 2026 results3,543 employees, the completed move from France to Luxembourg and the planned move to the US in January 2027, OpenAI's first ad tech partner, and restructuring costs (5 August 2026)
- 04Reddit r/developpeurs, working at Criteoan employee on the loop (HR, two or three LeetCode questions over two interviews, system design, culture fit), junior pay around €64K total, and the return to office (December 2025)
- 05Reddit, Criteo pair programmingflood fill, the HackerRank pad over video, the online chess design and a behavioural rejection for two petty reasons (July to August 2024)
- 06Reddit, a Criteo Paris offeran offer at a lower level after the design round, €57K fixed with 10% bonus and €19K stock (March 2025), and the online chess design in detail (March 2026)
- 07Reddit, Criteo interviewan easy sliding window from O(n²) to O(n) (May 2025)
- 08Reddit, Criteo technical assessmenta 90-minute assessment of 37 questions (September 2025)
- 09Reddit, Criteo pair programming testa one-hour pair programming test and whether it is still flood fill (December 2025)
- 10Reddit, Criteo junior paya junior base of €52K to €55K with an 11% bonus (August 2025)
- 11Reddit, Criteo Paris and hiring in Romaniaa candidate asking whether Paris is still growing (July 2026)
- 12Levels.fyi, Criteo software engineer pay in Francethe €57.9K to €150K+ range and monthly totals from L2 to L6 from 217 submissions (26 September 2026)
Interview processes change. This reflects widely-reported and sourced conditions as of 2026 — confirm specifics with your recruiter, and treat it as a map rather than a guarantee.
Prep for a real Criteo role
Practise your Criteo interview, out loud.
Paste a real Criteo posting and Calibrd predicts the questions for that role and level, benchmarks the pay, and flags the gaps an interviewer will probe in your CV — then listens to your spoken answers and coaches them. Your first mock is free.
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