Free practice for the Optiver online assessment.
80-in-8, Beat the Odds, NumberLogic, Likelihood List, Intervals, Orderbooks and Zap-N, on the real clocks, with a lesson for every question type.

You get one attempt at the Optiver online assessment every eight months. OptPrep lets you sit it as many times as you like first: the same clocks, the same scoring, fresh questions every time, and a lesson that shows you why each wrong answer looked right.

Start

Open coflazo.github.io/optprep in any browser. You install nothing, and it keeps working offline after the first visit. Your browser's Install button puts it on your dock or home screen.

To run it yourself on macOS, Linux or Windows, you need Node 20 or newer:

npx optprep

Or from the source:

git clone https://github.com/Coflazo/optprep.git
cd optprep
npm start            # or: python serve.py

Your progress stays on your device. Settings has backup and restore, and optional sync to a private gist in your own GitHub account, encrypted with a passphrase if you add one.

What you practise

Pick the battery you will sit, and OptPrep matches the tasks and clocks to it.

Battery	Tasks
Career Kickstarter: Trading	Beat the Odds, NumberLogic, Likelihood List, Intervals (45 s each), Orderbooks, Zap-N
Trader and Quant Trader	80-in-8, NumberLogic (15 in 25 min), Beat the Odds (30 questions), Likelihood List, Zap-N
Everything	Every task at its most commonly reported format

Task	Exam replica	Scoring
80-in-8	80 questions in 8 minutes, tap to answer, no going back	+1 right, −1 wrong
Beat the Odds	20 questions, 90 s each	+1, −1, or skip for 0
NumberLogic	26 sequences in 25 minutes, skip and return	+1, −1, or skip for 0
Likelihood List	15 sets of three statements, 90 s each	1 point for the exact order
Intervals	18 estimates, 60 s each	lower ÷ upper when the truth is inside
Orderbooks	20 boards in 8 minutes	boards solved; a wrong submit costs 5 s
Zap-N	9 games	each scored against the best possible play

After the online assessment, Optiver's interviews include market-making games. OptPrep's bonus round has you quote two-sided markets against a trader who knows more than you.

How it compares

Paid prep exists for parts of the Optiver online assessment. Here is what each product's own pages say it covers, next to OptPrep.

	Lowest listed price	80-in-8	Beat the Odds	NumberLogic	Likelihood List	Intervals	Orderbooks	Zap-N
OptPrep	Free	✓	✓	✓	✓	✓	✓	✓ 9 games
Tradermath	€24.95 / 2 weeks, renews	✓	✓	✓	✓	✓	✓	✓ 9 games
Aptitude Test Prep	$30 / 30 days		✓
QuantPrep	$35 + VAT / 2 weeks	✓	✓	✓
JobTestPrep	$39 / 1 week	✓		partly				partly
EverythingQuant	$39.99 / month	✓	✓	✓				Number Box

Prices and coverage come from each product's own pages on 2 October 2026. A blank cell means the page doesn't list that task. Prices change; if a row is out of date, open an issue and the next release fixes it. Every source link is in docs/compare/competitors.json. Free practice sites exist too, and this table lists only paid ones.

OptPrep also runs offline, needs no account, and is open source, so you can read how every question is generated and checked.

How you learn

Each task has a roadmap that runs from Foundations to Exam pace. A skill has five levels. Three clean answers in a row earn a level; the fifth also needs exam speed.

Lessons move in short steps. You meet one idea, answer a question on it, then move to the next.

Every wrong option in the question bank carries the belief that produces it. When you miss, OptPrep names the belief you used and walks you through the solution with a picture and the shortcut an expert takes inside the time limit.

OptPrep also keeps a list of the skills and beliefs that keep costing you points, with recent answers weighted more. One tap gives you ten questions on any of them.

Set a daily goal of five, ten or twenty minutes. Only time spent answering or reading counts toward it.

What it looks like

A wrong answer names the belief behind your pick, then shows the solution with a picture.	An exam ends with a scan down the sheet. The score prints in the corner.

 

Lessons go one step at a time, and every task runs on a phone.

Limits

• Optiver publishes no pass lines. The Ready mark means your last three full exams met OptPrep's bar, which sits above the lines candidates report. It lowers your risk. It cannot promise a pass.
• The battery changes between roles and years. Every format number lives in config/sections.js and config/presets.js with its source. If your online assessment looked different, open a format report and the next release will match it.
• Zap-Q, the personality questionnaire, has no right answers to practise. Answer it honestly and consistently.
• Software engineering, quant developer and quant researcher assessments are different tests. OptPrep does not cover them.

How the questions are checked

Every question family has a generator and an independent verifier. A second pipeline re-checks the whole library outside JavaScript:

• Orderbooks: every board re-solved by a C++ branch and bound.
• NumberLogic: every sequence searched by a C++ rule library, so no wrong option fits an equally simple rule.
• Beat the Odds and Likelihood List: probabilities re-simulated by C++ Monte Carlo.
• Intervals: truths recomputed in Python from the drawn figures.
• Zap-N: optimal play re-solved in C++ for Skyscraper, NumberBox, Figure It Out and Balloon.

npm test                                                  # JavaScript tests
(cd backend && uv run pytest -q)                          # Python tests
cmake -S engine -B engine/build && cmake --build engine/build && ctest --test-dir engine/build
(cd backend && uv run python -m oa_backend.pipeline)      # re-check the full library

Inside

Part	Language	What it does
App	JavaScript, no dependencies	Generators and verifiers, exam replicas, lessons, games, progress
Engine	C++20	Monte Carlo, orderbook search and game solvers behind a JSON-lines CLI
Backend	Python, standard library	Optional local server: SQLite progress, an exam forecast, the verification pipeline

The design system lives in src/ui/styles.css and in the Figma file.

Contributing

Format reports matter most: they keep the replicas honest. Code and question families are welcome too. Read CONTRIBUTING.md first.

License

MIT. OptPrep is a personal project by Coflazo, an econometrics student, shared for free. It is not affiliated with, endorsed by or connected to Optiver, and it contains no Optiver test content. Read the legal notice and the privacy notice.