Terms of Service

Effective August 2, 2026

These Terms of Service (the “Terms”) are an agreement between you and Fifteen Labs, Inc., a Delaware corporation (“Fifteen”, “we”, “us”). They govern your use of the Fifteen desktop application, our websites at fifteen.app, and the services behind them (together, the “Service”). By installing or using the Service, you agree to them. If you are agreeing on behalf of a company or other organization, you represent that you have authority to bind it, and “you” means that organization.

Our Privacy Policy explains how we handle personal data and is incorporated into these Terms.

1. The Service

1.1 What Fifteen is

Fifteen is a local-first desktop application for macOS that connects to messaging accounts you already hold — such as Telegram, Signal, WhatsApp, Slack, iMessage and Gmail — and presents them in a single client. The application runs on your computer and stores your data there. We also operate a small set of hosted services that support it: sign-in, subscription billing, encrypted storage for chats you choose to share, device key management, and an AI gateway.

1.2 Your licence

Subject to these Terms and to payment of any applicable fees, we grant you a limited, non-exclusive, non-transferable, non-sublicensable, revocable licence to install and use the application on devices you own or control, for your own personal or internal business use, for as long as this agreement is in effect.

1.3 Our ownership

The Service, including the application, our websites, our backend, and all associated software, designs, text, graphics, trade marks and documentation (“Fifteen Content”), is owned by us or our licensors and is protected by intellectual property law. Except for the licence in 1.2, we grant you no rights in it, expressly or by implication. You may not remove or obscure any proprietary notice.

1.4 Changes to the Service

We are actively developing Fifteen and may add, change or discontinue features. We will not materially reduce the core functionality of a paid plan during a billing period you have already paid for without offering you a pro-rated refund.

1.5 Pre-release features

Features labelled beta, preview or experimental are provided for evaluation, may be changed or withdrawn at any time, and are supplied “as is” without any warranty or support commitment.

2. Your account

You need an account to use the Service. You must be at least 16 years old, provide accurate information, and keep your sign-in credentials confidential. You are responsible for everything that happens under your account. Tell us promptly at support@fifteen.app if you believe it has been compromised.

If you use the Service as part of an organization, the organization's administrators may manage your membership, see organization-level billing information, and remove your access.

3. Connected accounts and third-party services

Fifteen works by connecting to accounts you hold with other providers. You authorise us and the application to access those accounts on your behalf, using the credentials or authorisations you supply, in order to provide the Service.

You are responsible for your relationship with each of those providers, and your use of their services through Fifteen remains subject to their terms. This matters more than it might sound:

• Some platforms restrict or prohibit access through unofficial clients. Connecting an account to Fifteen may breach that platform's terms, and the platform may rate-limit, suspend or permanently ban your account there. You connect accounts at your own risk.
• We have no control over those platforms. They may change or withdraw their interfaces at any time, which may break a Fifteen integration without notice.
• We are not responsible for the availability, accuracy, content, or conduct of any third-party service, nor for any loss arising from your use of one.

Your use of Google APIs through Fifteen is additionally subject to the Google API Services User Data Policy, including its Limited Use requirements.

4. Your content

4.1 Ownership

Your messages, files, contacts and everything else you bring into or create in Fifteen (“Your Content”) remain yours. We claim no ownership of them.

4.2 Where it lives

Your Content is stored on your own device unless you take an action that sends it elsewhere — sharing a chat, using an AI feature, or sending a message to a platform. We have no access to the data on your device, cannot retrieve it for you, and do not back it up. Keeping your own backups is your responsibility.

4.3 Licence to operate the Service

For the content that does reach our systems, you grant us a worldwide, non-exclusive, royalty-free licence to host, store, transmit and display it strictly as needed to provide the Service to you and to the people you have granted access. This licence exists only so that our servers may lawfully hold and deliver your data; it ends when the content is deleted. In practice almost all of that content is encrypted before we receive it, so what we hold is ciphertext.

4.4 Your responsibility for it

You represent that you have the rights necessary to store, transmit and share Your Content through the Service, and that doing so does not violate any law or any third party's rights. Because the Service handles the correspondence of other people as well as your own, you are responsible for complying with any laws that apply to you when you retain, export or share it — including consent requirements for recording or retaining communications in your jurisdiction.

5. Encryption, keys and recovery

Chats you share, and your private notes, are encrypted on your device before upload with keys derived from a root key held by your devices. We do not have that key and cannot decrypt your content.

You are responsible for the security of your devices and your recovery code, and for approving device-linking requests only from devices you actually control.

6. Sharing chats with others

The Service lets you share a chat with other Fifteen users. When you do:

• you confirm you are entitled to share that content;
• the recipients you grant access to can read the chat and its attachments, and may be able to copy or retain what they see;
• revoking a grant prevents future access, but cannot recall what a recipient has already read or copied;
• to make sharing possible, handles of your connected accounts are published in a lookup directory as described in the Privacy Policy.

We do not monitor shared content — we cannot, since it is encrypted — but we may suspend accounts or remove content when we receive a credible report of a violation of these Terms or of applicable law.

7. Acceptable use

You may not, and may not permit anyone else to:

• use the Service to send spam or unsolicited bulk messages, to harass, threaten or abuse anyone, or to distribute malware;
• use the Service for content that is unlawful where you are, including child sexual abuse material, or that infringes someone's intellectual property or privacy rights;
• access accounts, messages or data you are not authorised to access;
• reverse engineer, decompile or disassemble the Service, except to the extent applicable law forbids that restriction;
• resell, sublicense, rent or otherwise commercially exploit the Service, or use it to build a competing product;
• circumvent usage limits, spend caps, rate limits, licence checks or authentication;
• probe, scan or test the vulnerability of our systems, or breach their security, other than through a responsible disclosure to support@fifteen.app;
• place a load on our systems that disrupts them or degrades the Service for others, including through automated or scripted use beyond ordinary personal use;
• use the Service in violation of export control or sanctions laws, or make it available to any person or in any country subject to such sanctions.

We may suspend or terminate access that we reasonably believe violates this section, and where the circumstances allow we will tell you why.

8. AI features

The Service includes optional AI features. When you use them, the prompts and context you submit are sent through our gateway to a third-party model provider, as described in the Privacy Policy.

• Output is not reliable by default. AI output may be inaccurate, incomplete or misleading. You are responsible for reviewing it before relying on it, and you should not rely on it for legal, financial, medical or other professional advice.
• As between you and us, you own the output generated from your prompts, to the extent it is capable of ownership. Output is not necessarily unique — the same or similar output may be generated for others.
• Don't feed it what you shouldn't. You are responsible for the content you submit, including whether you are entitled to disclose other people's messages to an AI provider.
• Agent features run code on your machine. Where you use the agent panel to run a third-party agent locally, that agent is a separate product under its own terms, it acts with the permissions you give it, and you are responsible for what it does.
• Usage is metered. See section 9.

9. Fees and payment

9.1 Plans and fees

Some parts of the Service require a paid subscription. Current plans, prices and included allowances are shown in the app at the time you subscribe. Prices are exclusive of taxes unless stated otherwise.

9.2 Billing and renewal

Subscriptions are billed in advance through Stripe on a recurring basis, and renew automatically for successive periods until cancelled. By subscribing you authorise us and Stripe to charge your payment method for each renewal, and to retry a failed charge. You can cancel at any time from the billing settings in the app; cancellation takes effect at the end of the current period, and access continues until then.

9.3 AI usage charges

AI features are metered by token usage. Usage beyond your plan's included allowance is billed in arrears at the rates shown in the app. You can set a spend cap, and we will refuse requests that would exceed it — but you remain responsible for usage actually incurred under your account, including by agents you run.

9.4 Refunds

Fees are non-refundable except where these Terms say otherwise or the law requires it. If you believe you have been billed incorrectly, tell us within 60 days of the charge at support@fifteen.app and we will investigate in good faith.

9.5 Taxes

You are responsible for all sales, use, VAT and similar taxes on your subscription, other than taxes on our income.

9.6 Non-payment

If a payment fails, we may suspend the paid features of your account after giving you notice and a reasonable opportunity to fix it. Data on your device is unaffected by suspension.

9.7 Price changes

We may change prices with at least 30 days' notice before the change takes effect for you. If you do not agree, you may cancel before your next renewal.

10. Term and termination

These Terms apply from the moment you first use the Service until terminated.

• By you. You may stop using the Service and delete your account at any time from the app's settings, or by writing to support@fifteen.app.
• By us. We may terminate or suspend your account if you materially breach these Terms and do not cure the breach within 30 days of notice; immediately, if the breach cannot be cured or if continued access poses a risk to others or to the Service; or if we discontinue the Service, in which case we will give you reasonable notice and a pro-rated refund of prepaid fees.

What happens then. Your licence ends and your access to the hosted parts of the Service stops. We delete the account data described in the Privacy Policy. The data on your own device is unaffected and remains yours — but note that the app requires an account to operate, so you should export anything you need before deleting your account.

Survival. Sections 1.3, 4.4, 9 (for amounts already owed), 11, 12, 13, 14 and 17 survive termination.

11. Warranties and disclaimers

We warrant that we will provide the Service with reasonable skill and care.

Except as expressly stated in these Terms, the Service is provided “as is” and “as available”, and Fifteen Labs, Inc. disclaims all warranties, express, implied or statutory, including the implied warranties of merchantability, fitness for a particular purpose, title and non-infringement. We do not warrant that the Service will be uninterrupted, timely, secure or error-free, that it will remain compatible with any third-party platform, or that any data will be preserved without loss. Some jurisdictions do not allow the exclusion of implied warranties, so some of these exclusions may not apply to you, and nothing in these Terms limits any non-waivable statutory rights you have as a consumer.

12. Limitation of liability

To the maximum extent permitted by law, neither party will be liable for any indirect, incidental, special, consequential, exemplary or punitive damages, or for lost profits, lost revenue, lost data, or the cost of substitute services, arising out of or relating to these Terms or the Service, whether in contract, tort or any other theory, even if advised of the possibility of such damages.

To the maximum extent permitted by law, each party's total aggregate liability arising out of or relating to these Terms or the Service will not exceed the greater of (a) the amounts you paid us for the Service in the twelve months before the event giving rise to the liability, and (b) one hundred US dollars.

These limits do not apply to your obligations under section 9, either party's obligations under section 13, or to liability that cannot be excluded or limited by law — including liability for death or personal injury caused by negligence, for fraud or fraudulent misrepresentation, or, where applicable, for gross negligence or wilful misconduct.

You acknowledge that the allocation of risk in sections 11 and 12 is a fundamental part of the bargain, and that our pricing reflects it.

13. Indemnification

You will defend, indemnify and hold harmless Fifteen Labs, Inc. and its officers, employees and agents from and against any third-party claim, and any resulting damages, liabilities, settlements and reasonable legal fees, arising out of (a) Your Content, (b) your use of the Service in breach of these Terms or of applicable law, or (c) your breach of the terms of a connected third-party platform.

We will defend you against any third-party claim that the Service, as provided by us and used in accordance with these Terms, infringes that party's intellectual property rights, and will pay the damages finally awarded or agreed in settlement. If such a claim is made or appears likely, we may modify the Service, procure the right to continue using it, or terminate the affected subscription and refund the unused portion of your fees. This paragraph states our entire liability, and your sole remedy, for intellectual property infringement by the Service.

Each party's obligations under this section are conditioned on the indemnified party promptly notifying the other of the claim, giving the other sole control of the defence and settlement, and providing reasonable cooperation.

14. Feedback

If you send us suggestions, feature requests or other feedback, you grant us a perpetual, irrevocable, worldwide, royalty-free licence to use it without restriction or obligation to you. We would rather have your ideas than a legal reason not to hear them.

15. Copyright complaints

If you believe content made available through the Service infringes your copyright, send a notice to legal@fifteen.app including: identification of the work, identification of the material and where it is, your contact details, a statement of good-faith belief that the use is unauthorised, a statement under penalty of perjury that the information is accurate and you are authorised to act, and your signature. We will respond as the Digital Millennium Copyright Act requires, and we may terminate the accounts of repeat infringers. Content that is end-to-end encrypted is not readable by us, which limits what we are able to review.

16. Changes

We may change these Terms. We will post the revised version here with a new effective date, and for material changes we will give you at least 30 days' notice in the app or by email before they take effect. If you continue to use the Service after that, the new Terms apply. If you do not agree to them, stop using the Service and cancel any subscription before they take effect.

17. General terms

17.1 Governing law and venue

These Terms are governed by the laws of the State of Delaware, without regard to its conflict of laws rules, and the parties submit to the exclusive jurisdiction of the state and federal courts located in New Castle County, Delaware. Each party waives any right to a jury trial. If you are a consumer resident in the European Economic Area or the United Kingdom, nothing here deprives you of the protection of mandatory provisions of your local law, or of your right to bring proceedings in your local courts.

17.2 Force majeure

Neither party is liable for a failure to perform caused by events beyond its reasonable control, other than payment obligations.

17.3 Assignment

You may not assign these Terms without our written consent. We may assign them to an affiliate or in connection with a merger, acquisition or sale of assets.

17.4 Independent parties

The parties are independent contractors. Nothing here creates a partnership, joint venture, agency or employment relationship.

17.5 No third-party beneficiaries

These Terms do not confer rights on anyone who is not a party to them.

17.6 Notices

We may give you notice by email to the address on your account, or in the app. You give us notice by email to legal@fifteen.app. Notice is effective when sent.

17.7 Waiver and severability

A failure to enforce a provision is not a waiver of it. If a provision is held unenforceable, it will be modified to the minimum extent necessary to make it enforceable, and the rest of the Terms remain in effect.

17.8 Entire agreement

These Terms, together with the Privacy Policy and any order you place, are the entire agreement between you and us regarding the Service, and supersede any prior understanding on the subject.

18. Contact

Legal notices: legal@fifteen.app
Support and billing: support@fifteen.app

Fifteen Labs, Inc., a Delaware corporation
TODO — registered address, Delaware, United States