Terms of Service

These terms govern your use of Knowtarium: the web app at app.knowtarium.com, the tools that connect your AI agents to it (the knowtarium command-line tool and its MCP server), and the website at knowtarium.com. Knowtarium is operated by Magentix Studio UG (haftungsbeschränkt), Kaiserring 14-16, 68161 Mannheim, Germany (see the Imprint).

By creating an account or using Knowtarium, you agree to these terms.

Knowtarium is a knowledge base of markdown notes, organized in workspaces and folders, that you and the AI agents you connect work in. Notes are kept in the OKF format, every change records who made it, and changes can be undone.

Your notes are end-to-end encrypted: they are encrypted on your device before they reach our servers, and we can't read them. The Privacy Policy lists what we store and what we can and can't see.

• You must be at least 16 years old to create an account.
• You need an account with a working email address, which you confirm before you can sign in.
• An account is for one person. Keep your password and recovery key to yourself.
• You're responsible for what happens under your account, including what the agents you connect do with the access you give them.
• Tell us at once if you think someone else has got into your account.

Your password never leaves your device, and the keys that open your notes are protected by it. When you sign up, you get a recovery key, shown once. Store it somewhere safe.

If you forget your password, your recovery key gets you back in. If you lose both, nobody can recover your notes: not you, not us. We can't reset your password in a way that restores access, because we never have the keys. In that case you can start over with the same email address, which deletes every workspace in the account.

Your notes, attachments and everything else you put into Knowtarium remain yours. You give us only the right to store and transmit the encrypted copies as needed to run the service for you. We claim no other rights to them, and we can't read them.

You can export a workspace or all of them at any time, whatever your plan and even when you're over its limits. We recommend keeping your own backups by exporting from time to time.

You decide which agents to connect and what each one may access. An agent you connect acts on your behalf. The provider of the AI model behind it (for example the company that makes your coding assistant) receives whatever the agent reads, under that provider's own terms and privacy policy, not ours.

Knowtarium runs no AI models itself and sends nothing to a model on its own. You can disconnect an agent at any time; its changes stay recorded and can be undone.

Every account starts on the Free plan. Starter and Pro are paid subscriptions with more storage and more workspaces, billed monthly or yearly. Every plan includes every feature. The current limits and prices are on the pricing page, and the exact amounts are shown in the app before you buy.

Free

• Free costs nothing. It includes 500 MB of storage and one workspace.
• We may change the Free plan's limits. If a change lowers them, we tell you by email at least 30 days before it takes effect.
• There's no payment, so there's nothing to cancel: you can stop using it or delete your account at any time.
• If a Free account has no activity for 12 months (nobody signs in to or uses the web app, and no agent or command-line tool you connected makes a request), we delete it with every workspace in it. We email you 30 days and again 7 days before; any activity before then keeps the account. Because we can't read your notes, you can only export them by signing in. The rule never applies while the account has a paid subscription that hasn't fully ended: one that's active, paused, past due after a failed payment, or cancelled but running until the end of the period you've paid for. Once a paid subscription has fully ended, the account is a Free account and the rule applies to it, with the 12 months counted from when the subscription ended or from the last activity, whichever is later.

Starter and Pro

• Starter costs $5.99 a month or $59.88 a year, and includes 2 GB of storage and up to 5 workspaces.
• Pro costs $11.99 a month or $119.88 a year, and includes 10 GB of storage and unlimited workspaces.
• You buy them inside the app, billed monthly or yearly. A subscription is billed in advance for its period (a month or a year) and renews automatically at the end of each period until you cancel.
• You can cancel at any time from the app's plan settings, which open Polar's customer portal. Cancelling takes effect at the end of the period you've paid for, and you keep your plan until then. After its first year, a yearly plan can also end early with a refund (see below).
• If a renewal payment fails, Polar retries it over the next few weeks. You keep your plan for 7 days after the failed payment; after that your account is on Free until the payment goes through. If Polar's last retry fails, the subscription ends.
• If you delete your account, your subscription ends at once (see Ending your account below).
• When a subscription ends for any other reason, your account goes back to the Free plan. Nothing is deleted.

Changing your plan or billing period

You change your plan or billing period inside the app. An upgrade (from Starter to Pro, from monthly to yearly billing, or both at once) applies right away, and the difference in price is charged then. Every other change, such as a downgrade from Pro to Starter or a switch from yearly to monthly billing, applies at your next renewal: you keep your current plan and its limits until then, with no refund or credit for the rest of the period, and you can cancel the scheduled change in the app before it applies.

Ending a yearly plan after its first year

Once a subscription has been billed yearly for a full year (counted from the start of its first yearly billing period), you can end it at any time and get back the unused whole months of the year you've paid for. Email us at support@knowtarium.com from your account's email address. We end the subscription and refund one twelfth of that year's payment for each whole month left; a month that has already started isn't refunded. Your account then goes back to the Free plan. During the first year, cancelling works as described above.

When an account is over its plan's limits

If your account holds more than its plan allows (for example after a paid plan ends or a downgrade applies), nothing is deleted. While you're at or over the storage limit, you can't save changes or add data. That includes creating folders, giving a folder or workspace a longer name, and changing your agent settings, except to turn on review ("Ask me first"), which always works. Moving folders and shortening names keep working too. At the workspace limit, you can't create another workspace. Reading, exporting and deleting always keep working. To get back under, delete attachments or a workspace, shorten a workspace's history, or upgrade. A deleted note stays in its workspace's history, and keeps counting, until the history period the workspace's owner chose has passed.

Starter and Pro are sold by Polar Software, Inc. (Polar), acting as merchant of record. Polar is the seller of record for the purchase: it runs the checkout, takes the payment, charges sales tax or VAT where it applies, and sends your receipts and invoices. Polar's buyer terms apply to the purchase; these terms govern your use of Knowtarium itself.

Prices in USD. VAT included where it applies; US and Canadian sales tax added at checkout. The checkout shows the total, including any tax for your location, before you pay.

If we change a plan's price, the new price applies only to new subscriptions. Your subscription keeps its price unless you agree to the new one.

Withdrawal right (consumers)

If you buy Starter or Pro as a consumer, you can withdraw within 14 days of the first payment of that subscription (for consumers in the EU this is also your statutory right). If you withdraw from your account's first paid subscription, whatever its plan or billing period, you get what you paid for it back in full, even if you've already used it; upgrading it within those 14 days doesn't make it a new subscription. If you withdraw from a later subscription, we refund what you paid less a proportionate amount for the days you already had the plan. A model withdrawal form is available on request from support@knowtarium.com. If you were charged by mistake (for example twice, or after you cancelled or deleted your account), we refund the amount in full. See Refunds for how refunds work in practice.

You agree not to:

• use Knowtarium for anything unlawful, or store or share content that is unlawful or infringes other people's rights;
• use it to spread malware or to attack other systems;
• probe, overload or disrupt our services, or try to get into other people's accounts or data;
• get around plan limits, rate limits or other technical limits, for example by creating accounts in bulk;
• resell or sublicense access to Knowtarium without our written permission.

Because your notes are encrypted, we don't and can't monitor them. We act on reports and legal orders, and on what our systems can see (such as unusual traffic).

OKF is an open format published by Google Cloud. Knowtarium is independent and isn't affiliated with or endorsed by Google. AI agents and MCP clients you use with Knowtarium are provided by third parties under their own terms.

Knowtarium includes open-source components, which are licensed under their own licenses.

We work to keep Knowtarium available and your data safe, but we don't promise any particular uptime, on any plan. Maintenance, faults and events outside our control can interrupt the service.

We may add, change or remove features. If we ever shut Knowtarium down, we tell you by email at least 30 days in advance, so you have time to export your notes; we stop charging for paid plans and refund any payment that covers time after the shutdown.

We are liable without limitation for intent and gross negligence, for injury to life, body or health, and under the German Product Liability Act. For slight negligence we are liable only for breach of essential contractual duties (duties whose fulfilment makes proper performance of the contract possible at all and on whose observance you may regularly rely), and in that case limited to the foreseeable damage typical for this kind of contract. Any further liability is excluded. This does not shift the burden of proof to your disadvantage.

You can delete your account at any time in the app. This deletes every workspace and its contents. If you have a paid subscription, deleting your account ends it at once: we cancel the subscription with Polar before anything is deleted. The rest of the period you've paid for isn't refunded automatically, but the 14-day withdrawal right for consumers still applies; see Refunds for how refunds work. If your yearly plan is past its first year, ask us to end it with a refund (see Plans above) before you delete your account. If you ever started a checkout and Polar can't be reached at that moment, the deletion is refused, nothing is deleted, and you can try again. If the deletion stops after your subscription was cancelled, it stays cancelled and you can try again. If a deletion of your account is already in progress (for example from another tab), a second one is refused. While the deletion runs, you can't start a checkout, and if you pay for a plan in a checkout you left open (for example in another tab), we cancel that subscription at once and refund it. If you're ever charged after deleting your account, email us at support@knowtarium.com and we refund it.

We can suspend or close an account for good cause, such as a serious or repeated breach of these terms, or when the law requires it. Where the law and the circumstances allow, we warn you first and give you the chance to export your notes. Your statutory rights remain unaffected.

We may change these terms for good reason, such as legal changes or changes to the service. We tell you by email about changes that matter before they take effect; if you don't agree, you can cancel your subscription or delete your account. The date at the top shows when the terms last changed.

German law applies, excluding the UN Convention on Contracts for the International Sale of Goods. If you are a consumer, this choice of law does not deprive you of mandatory protections of the law of your habitual residence. If you are a merchant, the place of jurisdiction is Mannheim.

We are neither obliged nor willing to participate in dispute resolution proceedings before a consumer arbitration board (§ 36 VSBG).

If any provision of these terms is invalid, the rest stays in effect.

Questions about these terms: support@knowtarium.com.