Legal
Last updated: 6 May 2026
By creating an account or using OpeningOS, you agree to these Terms. If you don't accept them, don't use the service. The service is operated from the European Union and these Terms are governed by French law.
You must be at least 16 years old to create an account on your own. If you are under 16, a parent or legal guardian must create the account for you and accept these Terms on your behalf. You are responsible for keeping your password secret and for everything that happens under your account. One account per person; no shared accounts. We may close accounts that violate these Terms after notice.
OpeningOS is a chess opening training tool. It helps you import, organise and drill your own opening preparation. It does not teach openings, sell courses, or guarantee any particular improvement in your chess strength. The product evolves; we may add, change or remove features.
We offer a Free tier (limited to one repertoire and the Revision mode) and a Pro subscription at €15 per month or €120 per year (a saving of about 33%). Prices include VAT where applicable. Pro unlocks unlimited repertoires, every training mode, engine play-out, and full analytics. FIDE-titled players (FM, IM, GM and the women's equivalents) get Pro for free for life after one-time verification.
Pro subscriptions renew automatically at the end of each billing period (monthly or
yearly) at the then-current price. You can cancel any time from
Settings → Billing; your access continues until
the end of the period you've already paid for. We do not pro-rate refunds for partial
periods.
As an EU consumer, you have 14 days from the start of your first Pro subscription to withdraw and get a full refund, no reason required. To exercise this right, email billing@openingos.com before the 14-day period ends. The right of withdrawal does not apply to renewals of an existing subscription.
You agree not to:
The repertoires you import or build belong to you. You grant us only the limited license we need to host, display and process your content so we can run the service for you. You can export your repertoires as PGN at any time from the repertoire detail page, including after you cancel.
When you mark a repertoire as public, you grant other registered users a non-exclusive, royalty-free, revocable license to view and fork it. Revoking the share link revokes the license going forward (existing forks remain in their owners' accounts).
The OpeningOS software, brand, design and underlying source code are protected by copyright and trademark law. You may use them only as part of using the service as intended. No license is granted other than what is necessary to use the product.
You can close your account from Settings → Danger zone
at any time. We may suspend or terminate your account if you materially breach these Terms;
we'll give you reasonable notice except in cases of clear abuse, illegal activity, or
security risk. Upon termination, your data is deleted as described in our
Privacy Policy.
OpeningOS is provided "as is" on a best-effort basis. We aim for high availability but cannot guarantee uninterrupted service or freedom from bugs. To the maximum extent permitted by law, our aggregate liability to you for any claim arising out of the service is capped at the amount you paid us in the 12 months preceding the claim. Nothing in these Terms limits our liability for fraud or for damage we are not legally allowed to disclaim.
We may update these Terms. When we do, we update the date at the top and email you at least 30 days before the new version takes effect. If you don't accept the change, you can cancel your subscription before the new version applies.
These Terms are governed by French law. Any dispute that cannot be resolved amicably will be brought before the competent courts of Paris, France. EU consumers retain the right to bring proceedings in the courts of their home country, where local law allows.
Questions about these Terms? Write to legal@openingos.com.