Solving problems alone is not the same as solving them in an interview. In a real interview you have to think
out loud, handle hints, manage time and stay calm while someone watches. Mock interviews are the best way to
practice that, and you can do them for free.
What a good mock interview looks like
- 45 to 60 minutes, like a real interview
- One problem (sometimes two), chosen by the interviewer, not you
- Talk through everything: clarifying questions, your approach, complexity, edge cases
- Feedback at the end on communication, problem solving and code quality, not just “did it pass”
See the feedback from a real mock
From an SDE Skills mock algorithm interview: the interviewer walks through the four areas candidates are
scored on (requirements, problem solving, coding and verification).
How to practice coding interviews for free
- Pair up with a peer. Take turns as interviewer and candidate. Being the interviewer teaches you what
good answers sound like.
- Use a shared editor or a whiteboard, not your usual IDE with autocomplete.
- Time-box it. Stop at the time limit even if you are not done, then review.
- Write down feedback after each session and pick one thing to fix next time.
- Mix in daily problem practice to build pattern recognition between mocks.
Free mock interviews with SDE Skills
SDE Skills is a volunteer-run 501(c)(3) nonprofit for software engineers. Everything is free:
- Weekly system design and mock interview session: Saturdays, 9:00 AM Pacific, on Zoom
- Weekly data structures and algorithms session: Sundays, 8:30 AM Pacific, on Zoom
- Daily LeetCode practice: weekdays, 8:00 AM Pacific, on Zoom
- Discord community to find practice partners and ask questions any time
See the full schedule.
Join a session on Zoom
Find a practice partner on Discord
Common mistakes to avoid
- Jumping into code before clarifying the problem
- Going silent while thinking (narrate, even if it feels awkward)
- Ignoring edge cases and complexity until the interviewer asks
- Only practicing problems you already know how to solve
Preparing for design rounds too? Read How to Prepare for a System Design Interview.