Palantir's software engineering online assessment is commonly reported as a mix: algorithm problems plus practical tasks such as a SQL query or a REST API exercise. Readable code matters, because the OA is treated like a first-round interview. This page covers what the Palantir online assessment is, its format and timings, how it is scored, the rules to know before you start, how to prepare and a practice plan.
What the Palantir online assessment is
Reports from 2024 to 2026 mostly describe HackerRank, with CodeSignal in some invitations. One UK-focused guide claims the only pre-onsite coding happens in a phone interview, which conflicts with most reports, so go by your invitation.
Format and timings
| Part | What it involves | Time and questions |
|---|---|---|
| Algorithm problem | A LeetCode-style problem, often on graphs | Within the total time |
| SQL question | A practical query | Within the total time |
| REST API task | Call or parse an API response, often JSON | Within the total time |
Total: commonly reported as 60 to 120 minutes, most often about 90 minutes for three questions.
How it is scored
- Correctness on test cases plus readability, since a follow-up interview may review the code.
- No published cut-off.
Rules to know before you start
- Check which platform your invitation uses.
- Outside help is not allowed.
How to prepare
- Write readable code with brief comments and handle edge cases such as empty input, cycles and duplicates.
- Practice SQL queries and parsing JSON from an API.
- Review graphs, including topological sort and union-find.
- Be ready to walk through your solution in a later interview.
A practice plan
- Day 1: read the platform's candidate guide and try its practice environment.
- Days 2 to 4: two timed problems a day in your test language, writing your own edge-case tests.
- Day 5: one full mock under the real time limit.
- Day 6: review mistakes and the input and output rules.
- Day 7: take the test in one sitting with a stable connection.
Related guides: what an online assessment is, the HackerRank assessment guide, Palantir coding interview questions.
On the day, and the mistakes to avoid
- Check the platform, the allowed languages and the time limit in the invitation.
- Try the practice environment or tutorial so the editor and run buttons are not new.
- Use a reliable computer on a stable connection, with other apps and tabs closed.
- Read every problem before starting, and do the quickest ones first.
- Write and run your own edge-case tests before submitting.
- Keep a few minutes at the end to check output formats and resubmit if needed.
Mistakes that cost candidates:
- Writing an elegant solution that fails large hidden tests because of its complexity.
- Mismatched output formats: extra spaces, prompts or debug prints.
- Spending most of the time on one hard problem while easier points go unclaimed.
- Pasting code you did not write, which integrity settings can flag.
- Not reading the input limits, so a solution that works on samples times out.
What happens after the Palantir online assessment
If you pass, the next stage is usually a technical interview, and some interviewers ask about your assessment solution. Be ready to explain your approach and its complexity out loud, and prepare two or three behavioral stories for the conversations that follow. For the next stage, see software engineer behavioral answers.
Where CoPilot Interview fits
Online assessments are tests you take on your own: outside help is not allowed, and proctoring settings can flag other apps, tab switches or a second voice. Practice beforehand instead. CoPilot Interview is an AI interview assistant; its free AI mock interview prepares you for the interviews that follow the assessment, with questions built from your résumé and the job description and each spoken answer scored out of ten. The free plan gives 15 minutes a day of live help in sessions of up to 15 minutes, with AI mock interviews included. Read the invitation carefully and follow your employer's rules.
Disclosure: CoPilot Interview is our product, so weigh what we say about it accordingly.
Frequently asked questions
What is on the Palantir OA?
Commonly a coding problem, a SQL question and a REST API task, though formats vary.
Is the Palantir OA on HackerRank?
Most reports say HackerRank, with CodeSignal in some invitations.
How long is it?
Commonly 60 to 120 minutes, most often about 90.
Does code style matter?
Yes. Reports suggest reviewers treat it like a first-round interview, so readable code helps.
Can I use AI tools during the Palantir online assessment?
No, unless the instructions explicitly allow it. Assessments are meant to be taken on your own, and proctoring settings can flag other apps, tab switches or pasted code. Use AI tools to practice beforehand, and follow your employer's rules.
Practice this interview before the real one
The AI mock interview builds questions from your resume and the job description, reads them aloud and scores each spoken answer out of 10. Included on the free plan.
Start a mock interview