PM Interview Prep, Calibrated

Know what to practice next,
not just what question to answer.

PrepOS is an adaptive PM interview coach. Calibrate your target level, practice the highest-impact questions first, and track your readiness — all in your browser.

Start practicing

Reviewed questions: 250
Tracked concepts: 18
Target tracks: 6
Account required: None

Built for the loops that matter

APMPMSenior PMStaff PMAI PMPM-T

How it works

From cold start to interview-ready in three loops.

PrepOS is not a question dump. It picks the next rep, adjusts how much support to give, and tells you exactly what to fix before the retry.

Calibrate

Tell PrepOS your target level, interview date, weekly hours, and weakest area. The plan re-tunes the moment any of those change.

Practice

An adaptive queue surfaces the highest-impact next rep. Coach mode builds skills; Interview mode pressure-tests them.

Improve

A transparent six-axis scorecard names what worked, what to fix next, and the specific concept to revisit before the retry.

Why PrepOS

An interview coach with a memory and a method.

Most prep tools hand you questions. PrepOS hands you the right next question, then tells you whether your answer is at the target bar.

Six target tracks

APM, PM, Senior, Staff, AI PM, and PM-T — each with its own readiness bar and depth expectations.

Five-mode coaching ladder

Coach → Guided Practice → Light Feedback → Interview Practice → Maintenance. Support drops as mastery rises.

Concept mastery memory

Every rep updates per-concept confidence so the queue keeps closing the gaps that matter.

Source-aware question bank

Every prompt carries a reviewer, source type, and citation. No fabricated company claims.

Date-aware urgency

Within 10 days of your interview, PrepOS shifts toward harder, timed, interview-mode reps.

Transparent feedback

Six axes, no black box.

Every answer is scored on structure, user insight, metrics, trade-offs, communication, and target-level depth — with a named strength and the single fastest improvement.

Try the scorecard

By a PM, for PMs

Built by an aspiring PM. For the PMs ready to be next.

PrepOS started as my own interview lab — built across multiple PM loops when generic prep guides and free question dumps stopped earning their keep. Same question bank, rubric, and adaptive queue I still run before every onsite. Open-sourced so the next PM doesn't start from zero.

“The tool I wish I'd had the night before my first onsite — honest feedback, no marketing fluff, and the next rep always the right one. I still use it before every loop.”

— Built and used by an aspiring PM

Principle 01

Honest by default

MVP1 ships with a transparent keyword-and-structure rubric. LLM scoring is on the roadmap and will always be opt-in. No black-box numbers.

Principle 02

Source-aware questions

Every prompt names its reviewer and source type. No fabricated company claims, no scraped content from sources that disallow it.

Principle 03

Local-first by design

Your answers, scores, and progress live in your browser. No account, no analytics, no tracking — and the whole project is MIT-licensed on GitHub.

FAQ

Straight answers about how PrepOS works.

Is PrepOS free?

Yes. PrepOS is open source and runs in your browser. No account required.

Does it score answers with AI?

MVP1 uses a transparent keyword-and-structure rubric. LLM-based scoring is on the roadmap and will be opt-in.

How fresh is the question bank?

The bank ships with 250 reviewed prompts and is updated weekly. Every prompt has a reviewer name, source type, and (if applicable) citation.

Who is PrepOS for?

Candidates targeting APM, PM, Senior, Staff, AI PM, or PM-T loops at product-led companies.

Does my data leave the browser?

No. State is local. PrepOS does not collect or transmit your answers.

Practice the rep that moves your readiness — not just any question.