First session free — no signup

Practice the interview for the job you actually want.

Paste a job posting. Get original coding questions built for that exact role, then run through a real interview — approach, code, follow-ups — with an AI interviewer that scores how you think, not just whether the code runs.

Start your free mock interview →Takes about 20 minutes per question

Live preview

interviewer> Given a stream of incoming API request timestamps, write a function that returns how many happened in the last 60 seconds.

function requestsInLastMinute(ts, now) {
  return ts.filter(t => now - t <= 60000).length;
}

follow-up> What happens to this if it's called on every new request as traffic scales up?

78/100Correct, but this re-scans the array every call — O(n) per check. A sliding window would get this to O(1).

One real example, before you start

example.ts — from a real job posting
Job posting excerpt

"...Looking for a Backend Engineer with 3+ years in Node.js and distributed systems. Comfortable with concurrent request handling and API design..."

→ Generated question

5-8

Original questions generated per session

3

Independent scores per question — correctness, communication, reasoning

3

Languages supported — JavaScript, Python, Java

See it in action

Every screenshot below is the real product.

Approach first

It catches the gap before you've written a line of code.

State your plan out loud or in writing. A real flaw gets a guiding question back — never the answer handed to you.

approach.ts

interviewer>

Code + follow-ups

Follow-ups about the code you actually wrote.

Not a generic checklist. The question references your specific function, your specific choices.

JavaScriptPythonJava

function firstDuplicate(nums) {

const seen = new Set();

for (const n of nums) {

if (seen.has(n)) return n;

seen.add(n);

}

return null;

}

interviewer>

Session report

Scored on how you think, not just pass/fail.

Three independent scores per question, plus patterns that only show up across the whole session.

session-report.json
Correctness85
Communication60
Reasoning75

Pattern across this session

You consistently skip stating time complexity until asked directly — worth leading with it next time.

How it works

01

Paste the posting

A URL or the raw text. We extract the tech stack, seniority, and focus areas.

02

Get your questions

5-8 original questions, a genuine mix of difficulty, built specifically for that role.

03

Run the interview

Approach, code, follow-ups, scored — question after question, like the real thing.

Not another question bank.

Every part of the flow is built to feel like an actual interview, not a coding quiz.

Freshly generated, every time

No question banks, no LeetCode reskins. The model reads your posting and invents 5-8 original questions tailored to the exact role — every session is a different set.

Approach before code

A real interviewer doesn't hand you a blank editor. You explain your plan first — flawed reasoning gets a guiding question, not a lecture.

A real code editor

Monaco, the engine behind VS Code. JavaScript, Python, and Java, syntax-highlighted.

Follow-ups that read your code

Complexity, scaling, edge cases — asked about the specific function you just wrote, not a generic checklist.

Speak it, don't type it

Talk through your approach out loud and hear the interviewer respond, with a genuinely human-sounding voice.

A report that finds patterns

Not just per-question scores — it flags habits repeated across the session, like skipping complexity until asked.

Pricing

FREE first session

Full flow, every question, the whole report. No card, no signup.

$12 per session after

One new job posting, one new set of questions.

FAQ

You can — but you'd have to rebuild the interview discipline yourself every time: remembering to ask for the approach first, not caving and giving away the answer when someone's stuck, tracking follow-ups tied to the actual code, and scoring consistently. Codrill enforces all of that automatically, the same way every session, so the practice is actually comparable across attempts.

Your next interview is coming. Practice the one that matters.

Start your free mock interview →