Frequently asked questions

Short answers, with a link to the full guide where there is one. Still stuck? Email support@katabench.com.

Getting started

What is Katabench?

Katabench is hands-on .NET practice. The puzzle catalog covers seven disciplines: algorithms, Database / EF, refactoring, architecture, secure coding, design principles, and test writing. Correctness is only one part of the evidence; applicable exercises can also grade time, allocations, query plans, code structure, design constraints, security behavior, or test effectiveness.

Katabench Labs extend that practice into guided multi-file projects. The How it works page is the product overview.

Do I need to install anything?

No. Puzzle editing and grading happen through the browser. Labs, when available, also provide their project workspace through the browser. You do not need a local SDK or Docker installation for the hosted experience.

Which languages can I use?

Puzzle submissions use C# 12. Katabench is intentionally focused on the .NET ecosystem so its feedback can be specific. See The editor & runtime for the language and library boundaries.

Can I use Katabench on a phone?

Yes. The Playground switches among Problem, Code, and Results views, and Labs switch between Guide and Code & output. A desktop is more comfortable for large multi-file katas, terminals, and detailed query plans.

Is it really free?

Yes. Free requires no credit card and includes the full algorithms catalog plus the other features shown on Pricing. Plans, limits & billing explains how separate run, submission, and reveal allowances work.

Grading & results

What is the difference between Run and Submit?

Run executes visible samples and optional custom input. It does not use a submission. Submit grades the full suite, including hidden checks, and uses the submission allowance on Free. Run and Submit have separate daily allowances. See Getting started.

Why did Submit fail when Run passed?

Run proves only the visible examples. Submit adds hidden edge cases, larger inputs, and any track-specific quality gates. Open the Tests tab, use Only failing, and read the quality scorecard. Troubleshooting gives a diagnosis order.

Where do timings come from?

Timings are measured in the grading environment around your code, not in the browser and not across your network connection. This makes puzzle speed standings comparable. Normal small timing variation still exists, so prioritize clear headroom.

Can I see hidden test inputs?

No. Hidden tests show their name, status, timing, and applicable rule or budget evidence, but not the input or expected and actual values. Visible tests show the detailed difference you need for ordinary debugging.

Is revealing the solution cheating?

No. Reveal is a study tool. It replaces the editor with a correct reference, uses the reveal allowance when applicable, and does not mark the puzzle solved. Read it, Reset, and reproduce the approach from memory.

What marks a puzzle solved?

Only a clean graded Submit. Passing Run, opening every hint, or revealing the solution does not mark completion. One solve can also count toward every learning path that contains that puzzle.

Learning and progress

What is the difference between a track and a learning path?

A track is a discipline used to group similar puzzle types. A learning path is an ordered curriculum that selects exercises, groups them into sections, and tracks a finish line. You can solve the same exercise from either the path or the open catalog.

What is the difference between a puzzle and a Lab?

A puzzle is a focused graded coding task. A Lab is a guided project workspace containing ordered lessons, multiple files, application output or terminals, and an executable Check step. See Working through Katabench Labs.

How do XP, gems, and streaks work?

Successful signed-in practice can award XP and gems and extend your streak. Daily challenges, quests, achievements, paths, and Labs can add rewards. The app displays the exact value and condition for each current reward. Gems buy titles, themes, and streak freezes. See Progress, XP, streaks & rewards.

Why is my learning-path progress already partly complete?

Path progress uses solved puzzles. If you solved an exercise earlier from the catalog or another path, the matching step is already complete. This is intentional.

Plans & billing

What does Pro unlock?

Pro includes the premium puzzle tracks, full hidden performance suites, every guided path, the Pro Lab catalog when Labs is available, and removes daily run, submission, and reveal caps under fair use. The feature matrix is the current source of truth.

How do I manage or cancel a subscription?

Sign in, open Account & billing, and select Manage billing. The customer portal lets you update payment details, view invoices, or cancel. A cancellation keeps paid access through the date shown on the plan card.

How do refunds work?

See the Refund policy and Terms of Service. For an account-specific question, email support@katabench.com.

Account & data

What follows me to another device?

When signed in, solved and submission history, learning progress, Lab completion, XP, streaks, achievements, gems, badges, and owned rewards belong to the account. Your unfinished puzzle buffer, custom Run input, revealed hints, and some view preferences are stored in the current browser.

What happens if I clear browser data?

Local editor buffers and browser preferences can be removed. Signed-in server-backed progress stays with your account. Guest-only progress can be lost, which is why creating an account matters before clearing data or changing devices.

How do I report a bug or suggest content?

Email support@katabench.com. Include the puzzle, path, course, Lab, or lesson name; what you selected; what you expected; what happened; and whether retrying changed the result. Do not include passwords or payment-card details.