Prepvio
Sign up

Free mock interviews for software engineers

Practise technical interviews out loud.

An AI interviewer for coding, behavioral and introduction rounds — by voice or chat. It asks real follow-up questions, keeps the clock, and gives you a scored debrief when you finish. Free, no card.

Start practising free Continue with Google
03:40
Turn 1 · Clarifying edge casesPlain editor · Code trace
Prepvio AISpeaking

InterviewerBefore you code: what should happen if two intervals only touch at an endpoint, like [1, 3] and [3, 5]?

Candidate (Voice)

You (Voice)I'd treat touching endpoints as overlapping and merge them into [1, 5]. I'll also guard against an empty array.

solution.tsStage 1 · Clarifying
function merge(intervals: number[][]): number[][] {  if (intervals.length <= 1) return intervals;  // Sort by start time: O(n log n)}

Built for the pressure of a real loop

Solving problems silently in your head is different from explaining trade-offs out loud while a clock runs. Prepvio conducts structured, adaptive technical screens that probe your assumptions, trace your code line by line, and deliver a written rubric debrief the moment you finish.

01 · Adaptive Voice & Chat

Natural, probing interviews that dig into vague answers.

Speak naturally with hands-free voice or type in chat. When you pause, your answer sends automatically — and if you gloss over an edge case or say “we” instead of “I”, the interviewer follows up before moving on.

  • Barge-in support: interrupt or clarify mid-thought
  • Multi-turn follow-ups tailored to your exact response
Start a voice or chat round
02 · Stays in Character

Behaves like a real phone screen, not a hint-giving tutor.

During the round, Prepvio stays strictly in character — no premature hints, no praise, and no autocomplete crutch in the editor. It reads and traces your code the way human interviewers do, then switches to coach mode only after the clock stops.

  • Structured phases: clarifying, coding, dry-run & trade-offs
  • Post-interview “Ask the Coach” unlocked after completion
See all interview formats
03 · Scored Debrief & Time Replay

Know where every minute went and what to fix next.

Every completed session produces a rubric breakdown across problem solving, communication, and verification — backed by exact transcript quotes, a phase-by-phase time bar, and a keystroke replay of how your solution evolved.

  • Time split across clarifying, coding, and testing
  • Evidence-linked moments showing what helped or hurt your score
Get your first debrief free
Workflow

How it works

Three focused steps from setup to a scored engineering debrief. Interact with each stage below.

01Setup · 30 sec

Pick a round

Coding, behavioral or introduction. Choose how long, how hard, and whether you talk out loud or type.

Round Setup45 min · Medium
45m Coding · Medium · Hands-free mic
02Live loop · Voice or chat

Talk it through

The interviewer asks one question at a time and digs into vague answers. In voice mode you just speak; it waits for you to finish.

Phase 2 · Code Trace17:40

“Walk me through how your loop handles [1, 8] followed by [2, 4].”

prev[1] = Math.max(8, 4) → keeps [1, 8] without extra push
Plain editor · Interviewer reads live keystrokes
03Rubric · Time & replay

Get a report

Scores for each area, a hire signal and written feedback. Coding rounds also show where your time went and replay how you wrote the code.

Hire · 3.5/4
Problem solving4/4
Communication3.5/4
Verification3/4
Fix next: State space complexity before dry-running edge cases.
Round Formats

Interviews you can practise

Running your code is planned; today the interviewer reads and traces it, like many phone screens.

30–45 min · Plain editor Live now

Coding

A problem in a plain editor (no autocomplete, like a real screen), clarifying questions, a follow-up stage, and a review of your code by tracing it.

DSA · Plain editor (any language)

“Given a stream of timestamps and user IDs, design a rate limiter that allows at most K requests per sliding 60-second window.”

Follow-up probe: “Walk through your deque eviction when 3 requests arrive at the exact same millisecond.”
Practise coding
20–30 min · Follow-up depth Live now

Behavioral

Stories about conflict, ownership and impact, with follow-ups until the details are clear.

Leadership & Ownership · Multi-turn

“Tell me about a time you pushed back on a technical decision from a senior engineer or PM because you saw a production risk.”

Follow-up probe: “You mentioned the team agreed eventually — what concrete evidence or prototype changed their mind?”
Practise behavioral
5–10 min · Opening pitch Live now

Introduction

The first five minutes of a real loop: tell me about yourself, and what you'd want to be asked about.

Opening 5 min · Elevator calibration

“We have 45 minutes together today. To kick things off — walk me through your background and the system you’re most proud of shipping.”

Follow-up probe: “If I dug into that migration for the next 10 minutes, what was the hardest technical bottleneck?”
Practise introduction
On the RoadmapNext interview formats in development
Architecture & trade-offsSoon

System design

Capacity estimation, API contracts, storage partitioning & failure drills.

Coming soon.
Interfaces & stateSoon

Low-level design

Class hierarchies, concurrency invariants, extensibility & clean boundaries.

Coming soon.
Experience walkthroughSoon

Resume screen

Deep-dive questioning anchored directly on your past projects and impact claims.

Coming soon.
Capabilities

Built for real practice

Designed around how technical interviews actually run — without fluff or gamified distractions.

Voice engine

Hands-free voice

The mic stays on, a pause sends your answer, and you can talk over the interviewer to interrupt.

Hands-Free Mic Active1.2s pause

No push-to-talk button needed. Finish your thought, pause naturally, and your turn submits.

Realistic demeanour

Stays in character

No hints, no praise, no answers. It behaves like an interviewer, not a tutor, until you end the interview.

✕ Tutor hints: Off✓ Strict Screen: On
Candidate: “Is a min-heap the right approach here?”Interviewer: “What trade-off do you see compared to sorting upfront?”
Phase telemetry

See where the time went

The analysis shows how long you spent clarifying, coding and testing, and replays your typing.

04:12–23:05 · Implemented O(n log n) sweep + 38 keystroke snapshots.
Longitudinal rubric

Progress over time

Averages and trends per area across your interviews, with your weakest area called out.

Focus callout: Verification up +1.1 pts over 5 rounds
5-Round Rubric TrendAvg 3.4 / 4.0
2.2
R1
2.5
R2
2.9
R3
3.2
R4
3.6
R5
Post-round review

Ask the coach

After an interview, ask about it: what a better answer would have sounded like, or what to practise next.

“How could my STAR story be tighter?”

Cut the 70-second setup on legacy architecture down to one sentence, and state the latency drop (p99 840ms → 190ms) right when you describe the fix.

BYO key support

Bring your own Kiro key

Optional. Add a Kiro API key on your profile and the interviewer runs on Kiro under your account.

Zero setup required: Every account works out of the box on Amazon Bedrock with zero training on your data.
Transparency

Questions & answers

Everything you need to know about how Prepvio evaluates your rounds, handles code tracing, and keeps your transcripts private.

Data & Privacy GuaranteePrivate by default
  • Prompts & transcripts never train foundation models
  • Export or permanently delete your account anytime
Read Privacy Policy →Terms of Service →
Showing 5 of 5 questions
Code tracingDoes the interviewer run my code?

No. It reads and traces your code, the way many phone-screen interviewers do, and asks you to walk through inputs. Running code is planned.

Plain editorWhich programming languages can I use?

Any. The editor is plain text, so write in the language you'll use in the real interview.

Account privacyWho can see my interviews?

Only you. Each interview, transcript and score belongs to your account.

BYO Kiro keyWhat is the Kiro API key for?

Nothing, unless you want it. Without a key, Prepvio's interviewer runs on a model in Amazon Bedrock. With your own Kiro key, it runs on Kiro instead. If your key stops working mid-interview, the interview continues without it.

Zero AI trainingDo you use my interviews to train AI?

Prepvio's interviewer runs on Amazon Bedrock, which does not use your prompts or answers to train its models. If you add your own Kiro API key, your interviews run on Kiro under your account.

Ready when you are

Your next interview is the one that counts. Practise this one first.

Start a coding, behavioral, or introduction round in under thirty seconds. Free, with no card required.

Create your account Continue with Google
✓ Free daily rounds · No credit card
Preview your first session30–45 min · Medium
Coding Phone ScreenPlain editor + Voice or Chat

Clarify constraints, implement in any language, and dry-run edge cases out loud.

  • Rubric scores across problem solving, code & verification
  • Phase time breakdown (clarifying vs coding vs testing)
  • Full keystroke replay + post-round Ask the Coach
Start this coding round free