AI mock interviews for software engineers
Rehearse out loud.Walk in ready.
You know your stuff. Now practice saying it. An AI interviewer that listens, pushes back, and helps you find your next better answer.
- Free to start
- Just a browser and a mic
- Delete your data anytime
The interview room
Talk, code, and get grilled. In one tab.
The interviewer listens while you explain, follows up on what you said, and watches your code run against the tests.
Example coding round: the interviewer asks for two numbers that add up to a target, the transcript records the conversation, and a Python solution passes three sample test cases.
Questions you'll hear
Every round asks differently.
A sample from each round, asked out loud, with follow-ups drawn from what you actually say.
“Walk me through your background, and why this role now?”
“Design a URL shortener. Now traffic grows 10x. What breaks first?”
“What would you want to own in your first 90 days here?”
“What happens to your solution if the array is already sorted?”
“You said it kept growing. What number made you change the plan?”
“Walk me through the edge cases before you run it.”
“What are you looking for in your next team that you don't have now?”
“Can you get that below O(n log n)? What would it cost you?”
“Which project on your resume are you least proud of?”
“Return the indices of two numbers that add up to a target. Talk me through it as you go.”
“Tell me about a decision you changed your mind on.”
“Tell me about a time you disagreed with your manager and turned out to be wrong.”
“Where does the cache sit, and what do you do when it goes cold?”
“What would your last manager say you should work on?”
“What would you do differently if you had to make that call again?”
“Two regions disagree on a write. Which one wins, and why?”
“Tell me about a time you disagreed with a senior engineer.”
“How did you know it worked? What did you measure?”
Knowing it is only half the interview.
A correct answer gets you started.
How you explain it makes the difference.
Same question
“Find two numbers in an array that add up to a target.”
Both correct. 47 points apart on clarity.
Answer A
RamblesSo, um, I guess first I’d loop over it twice? (Hedging) Actually wait, no, a map. You put the numbers in and check if the other one’s there. I think that’s O(n)? Yeah. (Unsure of own result)
- Code correctness
- 92
- Clarity
- 41
- Problem framing
- 36
Answer B
StructuredBrute force is two loops, O(n²). (Frames the baseline) I’ll trade memory for speed: (Names the trade-off) one pass with a hash map from value to index, checking each complement as I go. O(n) time, O(n) space.
- Code correctness
- 92
- Clarity
- 88
- Problem framing
- 84
Illustrative example, scored on three of the dimensions in Composur's coding rubric.
How it works
Three steps to a better answer.
Each round leaves you with something specific to fix before the next one.
- 01
Pick your interview.
Choose the role, your level, and the round. Add your resume and the job description, and the questions follow the job you want.
New interviewRole
Backend Engineer
Level
MidSeniorStaff+Round
CodingSystem designBehavioralBar raiserStart interviewResume
resume.pdf
Job description
Payments, Backend
- 02
Answer out loud.
The interviewer listens and asks follow-ups on what you actually said. Code rounds get a real editor, design rounds a whiteboard.
System designLive“Design a URL shortener. Now traffic grows 10x. What breaks first?”
The write path is fine. Reads are 100 to 1, so the database melts first. I'd put a cache in front, keyed on the short code.
Follow-up
“What's your cache hit rate, and what happens on a miss storm?”
- 03
Replay and fix.
Watch the recording, read the transcript, and see your scores on the rubric for that round, with notes on what to change next time.
Behavioral round, reviewed14:28- Problem framing
- 86
- Structured communication
- 74
- Depth under follow-ups
- 68
- Ownership & influence
- 91
Next rep
Name the trade-off in your first two sentences.
Role
Backend Engineer
Level
Round
Resume
resume.pdf
Job description
Payments, Backend
The whole loop
One platform. Every round.
Most tools cover one round. Composur covers the loop, from the recruiter screen to the bar raiser.
The interviewer asks
“Walk me through your background, and why this role now?”
Voice
Scored on
- Problem framing
- Structured communication & clarity
- Depth under follow-ups
- Evidence & specifics
- Role & domain fit
Domain and low-level design rounds are in there too. Pick your level, from entry to staff-plus.
Inside Composur
Built for the weeks before the offer.
Everything stays in one place, so each session builds on the last.
Replay every moment.
The recording and a timestamped transcript, with the moments that mattered marked for you.
Tell me about a decision you changed your mind on.
We committed to shipping the rewrite in one release…
The trade-off was speed against migration risk.
What convinced you to split it up?
Notes you can act on.
Specific, timestamped feedback: what worked, and what to change before the next round.
Named the trade-off early
04:26, first two sentences
Code that actually runs.
Python, Java, or C++ in a VS Code-grade editor. Run it against test cases and keep talking.
See yourself improve.
Every session is saved with its score, so you can see what is getting better.
Overall score
+20 in 4 rounds58
Oct 17
67
Oct 21
71
Oct 24
78
Oct 28
Your practice stays private.
Never sold, never used to train AI.
- Speech transcription
- On your device
- Used to train AI
- Never
- Delete everything
- Anytime
FAQ
Questions, answered.
A recent version of Chrome, Safari, or Edge and a working microphone. Firefox is not currently supported. A webcam is optional. Speech recognition runs on your device, so the first session downloads a speech model and may take a moment to start. Run the voice check before your first interview to make sure your mic works.
Yes. Before each session you choose the role you're preparing for, your experience level, and the kind of interview you want to practice.
After the session you get an overall score out of 100 plus dimension scores that depend on the interview type. You also get a short summary, your strengths, and the gaps worth working on next.
Practice questions across roles and difficulty levels, covering coding, system design, and behavioral topics. Some questions are tagged with the companies known to ask them.
Yes. From a recording, you can create a share link to send to a mentor or friend. You can turn the link off at any time.
No. We don't sell your personal information, recordings, transcripts, or code, and none of it is used to train AI models.
Go to Settings, open Danger zone, and choose Delete account. This permanently removes your account along with your recordings and scores.
Your next interview starts here.
Make your next
answer your best.
Practice the pressure. Find your words. Walk into the real conversation knowing you’ve been here before.