LetterlockTerms of Service
Last updated: 24 August 2026
1. Who you are contracting with
These terms govern your use of Letterlock, provided by the party named in the Imprint (“we”, “us”). By connecting a Google account you accept them. If you do not, do not connect one.
2. What the service does
Letterlock connects to your Gmail and Google Calendar and, on your behalf: drafts replies to incoming mail, saves those drafts in your own Gmail drafts folder, optionally creates calendar events from mail you have sent, and optionally sends you a daily summary and notifications.
It never sends mail. Every reply it writes is a draft that sits in your drafts folder until you read it, edit it, and send it yourself. This is a design constraint enforced in the code, not a setting, and there is no configuration that turns it off.
3. This is beta software
Letterlock is early. It will draft things that are wrong, miss mail you expected it to handle, and occasionally be unavailable. Read every draft before you send it. Do not rely on it as the only route by which something important reaches you, and do not treat a draft as reviewed advice on anything — legal, medical, financial, or otherwise. You remain the author of everything you send.
4. Your account
You need a Google account, and you must be entitled to grant access to the mailbox you connect — your own, or one you are authorised to act for. If the mailbox belongs to an employer or a client, that is a decision for them as much as for you, and connecting it is you telling us that you may. Keep your Google account secure: whoever controls it controls what Letterlock can reach.
You must be 16 or older.
5. What you may not do
Do not use Letterlock to send spam or bulk unsolicited mail, to impersonate anyone, to process mailboxes you have no right to, to break any law that applies to you, or to attack the service or the machines it runs on. Do not attempt to use it as a general-purpose AI proxy by feeding it content that is not your mail. We may suspend an account that does these things, and will tell you why.
Security research is welcome. Testing against your own account is fine; testing against someone else's is not. Tell us what you find before you tell anyone else.
6. Price and payment
The subscription is €25 per month. Payment is handled by Polar as Merchant of Record: they take the payment, issue the invoice, and handle VAT, and your payment details never reach us. Your subscription renews monthly until you cancel it, which you can do at any time from the Billing page. Cancellation takes effect at the end of the period you have paid for; we do not pro-rate a part-month.
If a payment fails or a subscription lapses, the account stops being processed. Nothing is deleted for non-payment; connect a working payment method and it resumes.
If we change the price, we will tell you at least 30 days before it applies to you, and you can cancel before it does.
7. Right of withdrawal
As a consumer in the EU you normally have 14 days to withdraw from a contract concluded at a distance. Because this is a digital service that starts immediately, you are asked at checkout to agree that we begin performance right away and to acknowledge that you lose the right of withdrawal once we have. If you would rather keep the 14 days, do not give that agreement — contact us and we will arrange it instead.
Nothing here limits your statutory rights, and none of it applies to you if you are subscribing as a business rather than as a consumer.
8. Availability
We do not promise any particular uptime. The service depends on Google, on an AI provider, and on a payment processor, and an outage at any of them is an outage here. We will do the obvious things — not deploying carelessly, fixing what breaks — but there is no service-level agreement and you should not build a business process on the assumption of one.
9. Your data
What we do with your mail is described in the Privacy Policy, which is part of these terms. In summary: it is used to run the service you asked for, it is masked before it reaches an AI model, it is not sold, shared for advertising, or used to train models, and you can delete it from the Account page.
Your mail and your drafts are yours. We claim no rights over them beyond what running the service requires. What you write into the voice profile and personal-context pages is likewise yours, and goes when your account goes.
10. The software
Letterlock is open source. The licence in the repository governs the code — what you may do with it, copy it, run your own instance — and these terms govern the hosted service we run for you. They are separate things and the licence does not give you a claim on the hosted service.
11. Ending it
You can stop at any time: cancel the subscription, delete the account, or withdraw our access from your Google account settings. Any of the three ends the processing; the Account page's delete does all of it at once.
We may end it too, with reasonable notice, if you breach these terms, if we cannot serve you lawfully, or if we discontinue the service. If we discontinue it, we will give you notice with enough time to export what you want to keep, and refund the unused part of a period you have paid for.
12. Liability
We are liable without limit for injury to life, body or health, for damage caused intentionally or by gross negligence, and under the Produkthaftungsgesetz. For ordinary negligence we are liable only where we breach an obligation essential to the purpose of this contract, and then only for the foreseeable damage typical of a contract of this kind. Beyond that, liability is excluded.
Concretely, and without narrowing the paragraph above: we are not liable for a draft that was wrong, for mail that was not processed, for a calendar event that was not created, or for anything you sent after reading it. Reviewing a draft before sending it is your part of this, and it is the whole reason the service does not send.
13. Changes to these terms
We may change these terms. If a change matters to you we will give you at least 30 days' notice by email or notification, and if you do not accept it you can cancel before it takes effect. Continuing to use the service after that means you accept the new version.
14. Law and jurisdiction
German law applies, excluding the UN Convention on Contracts for the International Sale of Goods. If you are a consumer, this does not deprive you of the protection of the mandatory law of the country you live in, and you may bring proceedings where you live. If you are contracting as a business, the place of jurisdiction is the seat of the provider named in the Imprint.
15. If part of this fails
If any provision here turns out to be invalid, the rest stays in force, and the invalid one is replaced by the applicable statutory rule.
See also the Privacy Policy and the Imprint.