1. Operator and acceptance
Brainbunk is independently operated in Finland by Peter Lindroos. Questions can be sent to support@brainbunk.com.
By using Brainbunk, you agree to these Terms of Use. If you do not agree, do not use the service or create an account.
Effective date and version: 11 September 2026, version 2026-09-11.
2. The service
Brainbunk provides seven free browser-based games: Sudoku, Grid Sweep, Nonograms, Merge Grid, Block Fit, Chess, and Gomoku. Every game can be played without an account. An optional Brainbunk account can synchronize supported game saves and statistics across devices or browsers.
Gomoku uses freestyle rules on a 15 × 15 board: Circle moves first and the first horizontal, vertical, or diagonal line of five or more marks wins. Its TypeScript Computer Opponent runs locally in a Web Worker, does not use an LLM, and stores one validated game only in the current browser.
Chess can be played without an account against the locally running Stockfish 18 engine. One Stockfish game and the last-used Chess mode are saved only in the current browser. Signed-in users can instead play White against OpenAI Luna; Luna moves, positions, results, selected opponent and model, and history are validated and stored with the account for restoration.
Ordinarily, each account may start up to three Luna games during a weekly period beginning Monday at 00:00 UTC. Brainbunk may server-authorize designated operator or internal testing accounts to be exempt from this weekly start limit. An exemption is account-specific, non-transferable, and may be removed at any time. Starting a replacement counts as another game for an account subject to the limit; restoring an existing game does not. A Luna game that remains active after 200 plies is recorded as a draw. Local Stockfish games do not use this allowance.
Brainbunk is provided for personal entertainment. Statistics and local saves come from browser-controlled clients and are not verified competitive records. Luna and the selectable Stockfish or Gomoku difficulty presets do not create a rating or guarantee a particular playing strength, style, response time, availability, or uninterrupted preservation of a game.
3. Accounts
You must be at least 13 and legally able to agree to these terms to create an account. If the law where you live requires parental or guardian authorization at a higher age, that authorization is required.
You are responsible for providing a working email address, keeping your email-password, Google, or Microsoft credentials secure, and contacting Brainbunk if you suspect unauthorized access. Do not attempt to access another person’s account or data.
Accounts with no sign-in or recorded account activity for more than 12 months may be deleted during an account review, which is performed at least once a year.
You can delete your Brainbunk account from Account Information. This deletes the account, linked cloud game data, and Luna positions and move history. It does not delete browser-local Stockfish or Gomoku games or change your Google Account, Microsoft account, or data held by those services.
4. Acceptable use
Do not use Brainbunk unlawfully or misuse it to interfere with the site, bypass security, usage limits, or access controls, probe another user’s data, distribute malicious code, automate disruptive requests, or misrepresent game results as independently verified.
Brainbunk may restrict or suspend access when reasonably necessary to protect the service, its users, or others, or to respond to unlawful or abusive use.
5. Game data and availability
Local saves and statistics depend on browser storage and may be lost if site data is cleared, storage is blocked, or you change devices. Account synchronization is a convenience feature and is not a guaranteed permanent backup. Keep any information that matters to you separately.
Brainbunk may fix, change, temporarily interrupt, or discontinue a game or feature. Reasonable efforts will be made to avoid unnecessary data loss and to communicate a significant planned discontinuation when practical, but uninterrupted availability cannot be guaranteed. Luna depends on OpenAI and may be temporarily unavailable while local Stockfish remains available after its engine files have loaded or are cached.
6. Intellectual property and feedback
Brainbunk’s site design, software, text, graphics, and branding are owned by the operator or used with permission. You may use the service for personal, non-commercial play, but you may not copy, redistribute, sell, or present Brainbunk content as your own except where applicable open-source licences or law allow it.
The local Chess engine is Stockfish 18, distributed under the GNU General Public License version 3 with authorship, licence, and exact source links included beside the engine files and from the Chess interface.
If you believe content on Brainbunk infringes your rights, or you want to send feedback, contact support@brainbunk.com with enough information to understand the issue.
7. Third-party services
Brainbunk uses Supabase for optional accounts and account-linked data, OpenAI to generate moves for the optional Luna Chess opponent, Google for optional sign-in and consent-based Analytics, Microsoft Entra ID for optional Microsoft sign-in, Hetzner for VPS hosting in Finland, and OVH for domain, DNS, and email services in France. Local Stockfish runs in your browser and is not a remote data processor. Luna, social sign-in, and Google Analytics are separate features.
8. Responsibility and statutory rights
Brainbunk is a free service provided with reasonable care and on an as-available basis. To the extent permitted by law, the operator is not responsible for indirect loss, lost browser data, or interruptions caused by networks, browsers, third-party providers, maintenance, or events outside reasonable control.
Nothing in these terms excludes responsibility that cannot legally be excluded or limits any mandatory consumer or data-protection rights that apply to you.
9. Privacy
See the Privacy Notice and Cookie and Storage Notice for information about accounts, browser storage, analytics, service providers, retention, rights, and account deletion.
10. Changes, questions, and disputes
These terms may be updated when the service or legal requirements change. Material changes will be communicated through the site when practical, and the effective date above will be updated.
If you have a question or dispute, please first email support@brainbunk.com so it can be discussed and, where possible, resolved informally.
These terms are governed by Finnish law, without removing mandatory rights or legal remedies available to you under the law of your country of residence.