Byteboard replaces puzzle-style questions with a realistic task: you review a short technical design document and answer trade-off questions, then implement features in an existing codebase. Trained human graders score the work against a rubric. This page covers what the Byteboard interview 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 Byteboard interview is
Byteboard spun out of Google's Area 120 incubator in 2021 and was acquired by Karat in January 2025, which is combining it with its human-led interviews. Lyft is named in a Byteboard case study, and candidates report it at companies such as Figma.
Format and timings
| Part | What it involves | Time and questions |
|---|---|---|
| Design document | Read a design doc for a planned feature and answer questions on trade-offs | Commonly reported: about 30 minutes |
| Codebase tasks | Implement functionality or fixes in an existing codebase | Commonly reported: about 60 minutes |
Total: commonly reported as about 90 minutes, done on your own schedule; varies by employer and domain.
How it is scored
- Trained, calibrated human graders score 20 or more job-related skills with structured rubrics.
- The report reaches hiring managers anonymized.
- Questions are usually the same across levels in a domain; seniority changes the bar.
Rules to know before you start
- You do it asynchronously, so pick a quiet 90-minute block.
- State your assumptions in the design section so graders can follow your reasoning.
How to prepare
- Do not spend too long on any one design question.
- Do the quicker coding tasks first; the last task is often the largest.
- Practice reading and changing an unfamiliar codebase quickly.
- Write readable code with brief comments, since humans grade it.
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, the CodeSignal assessment guide.
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 Byteboard interview
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 a Byteboard interview?
A project-based technical interview: a design document with trade-off questions, then coding in an existing codebase, graded by trained humans.
Is Byteboard part of Karat?
Yes. Karat acquired Byteboard in January 2025.
How long is Byteboard?
Commonly reported as about 90 minutes: 30 on the design document and 60 on coding.
Who grades Byteboard?
Trained human graders using structured rubrics, with anonymized reports for hiring managers.
Can I use AI tools during the Byteboard interview?
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