Self-host licence terms

Version 0.2. Last updated: 28 October 2026

These are the terms for running Kythene on your own infrastructure, under a Self-host Team licence or on the free self-host tier. Section 7 says what happens if a payment lapses, section 5 says who counts as a seat, and section 15 covers the free tier.

1. About these terms

These terms govern your use of the Kythene self-host software under a Self-host Team licence or on the free self-host tier. They are between you (the organisation buying a Self-host Team licence, or the person or organisation running the Software on the free self-host tier, "you") and Tamperan Ltd, trading as Kythene ("we", "us"), a company registered in England and Wales (company number 17324867) whose registered office is at Piccadilly Business Centre, Aldow Enterprise Park, Manchester M12 6AE.

They apply when you run Kythene on your own infrastructure, under a Self-host Team licence or on the free self-host tier. The hosted service at kythene.com, and our website, are covered by our general Terms and conditions. Where you run the Software on your own infrastructure and both documents cover it, these terms take precedence.

If you agree to these terms on behalf of an organisation, you confirm you have the authority to do so.

2. What the words mean

Software - the Kythene self-host application, including the container images we publish, the kythe command-line client, and any updates we make available during your Term.

Instance - one running deployment of the Software that you operate.

Seat - one person with their own sign-in to your Instance. Section 5 explains how seats are counted.

Guest - a person who reads, comments on or approves work in your Instance through a share link, without a sign-in of their own. Guests are not Seats.

AI agent - an AI client connected to your Instance, whether over MCP, the API or the command-line client, acting for a person who has a Seat. AI agents are not Seats.

Term - the period your licence is paid for, as set out in section 6.

3. What you may do

For as long as your licence is valid, we grant you a non-exclusive, non-transferable, worldwide licence to:

• install and run the Software on infrastructure you control, for as many Instances as you need;
• allow your Seats, Guests and AI agents to use those Instances;
• make copies for backup, testing, staging and disaster recovery.

This licence is for your own organisation's internal business use.

When your licence ends, you may keep running the Software in the read-only state described in section 7, to sign in, read, search and export your own data.

4. What you may not do

You may not:

• redistribute, resell, sublicense, rent or lend the Software to anyone else;
• operate the Software as a service for third parties, whether or not you charge for it;
• remove, obscure or circumvent licensing, attribution or enforcement mechanisms in the Software;
• reverse engineer the Software, except to the extent that restriction cannot lawfully be imposed on you.

Nothing here stops you using the Software with your own customers' data as part of your own business, provided they are not themselves using the Software other than as Guests.

5. Seats, and how they are counted

A seat is a signed-in human. You need one Seat for each person with a sign-in to your Instance. If you run more than one Instance, a person counts once however many of them they use.

Guests and AI agents are free. A person who reviews or approves work through a share link, and any number of AI clients connected over MCP, the API or the command-line client, do not need Seats and are not charged for.

The Self-host Team licence has a minimum of five Seats. Above that, buy one Seat for each signed-in human.

Your licence key carries the number of Seats you have bought, and each Instance admits people up to that number. To go above it, write to us and we'll add Seats to your licence; you then apply the updated key. The Software does not report your usage to us, and we do not audit your Instance.

6. Fees, tax and renewal

Self-host Team costs US$150 per Seat per year, with the five-Seat minimum, so the smallest licence is US$750 per year.

Your licence is annual and renews automatically on its anniversary until you cancel. We will charge the payment method on file for the coming year at the then-current price. If the price has changed, we will tell you at least 30 days before renewal.

You can cancel at any time by signing in to your account on www.kythene.com, and the cancellation takes effect at the end of the current Term. Purchases are made in the course of business, are non-refundable, and we do not refund part-used Terms. You keep full use of the Software until the Term ends.

Payment and tax. Purchases are processed by Stripe, which acts as merchant of record for the payment and adds VAT or sales tax at checkout where it applies. Prices are shown excluding that tax. Stripe's role covers the payment and its tax; the licence itself, and these terms, are between you and us.

If a renewal payment fails and isn't put right, your licence ends when the Term it paid for ends, and section 7 applies.

7. Licence keys, expiry, and what happens if you stop paying

Your Instance validates a licence key. Each key is short-lived: it is valid for up to 45 days, and never more than a few days past the end of the Term you have paid for. While your licence is current we keep issuing fresh keys. With automatic renewal on (section 8), your Instance collects them itself, and keeps them across restarts when it has a writable key file, as the self-hosting guide sets up; with it off, you apply a fresh key from your account on www.kythene.com before the current one expires.

If your key expires - because your licence has ended, for example after a renewal payment failed, or because a fresh key was not applied in time:

1. There is a grace period of 72 hours after the key expires, during which nothing changes and your Instance behaves normally. The grace period is set in your Instance's configuration (KYTHENE_LICENCE_GRACE), and you can make it longer or shorter.
2. After the grace period, your Instance becomes read-only. Everyone who already has a sign-in can still sign in, read and search everything in it, and your administrators can still export it. Creating and changing content is paused - for example publishing, versioning, remembering, commenting, reviewing and approving. Removing content still works, so you can delete a leaked secret and meet an erasure request.
3. Applying a valid key restores full function immediately, with no data loss and nothing to repair.

A lapsed licence will never stop your Instance from starting, and we will never make your own data unreachable to you. You are running a record of your team's decisions and knowledge, and a lapsed payment is not a reason for us to take that away. Read-only is deliberate: it is a prompt to renew, not a lock on the door.

This section is about a licence that has lapsed. A licence key that has been forged or altered, or that was issued for a different product, is not a valid licence, and the Software may refuse to run with it.

8. Your data

Your Instance runs on your infrastructure and your data stays there. We do not receive it, and we do not have access to it.

Your Instance validates its licence key offline, on your own servers. The only exception is automatic renewal. When it is switched on and your key is within seven days of expiry, or has expired, your Instance asks our storefront at www.kythene.com for a renewed key, by default no more than once every 12 hours. That request sends your current licence key and nothing else: no content, no list of users, no usage figures. The key holds only what we issued to you: its identifier, issuer and product, the subscription it belongs to, the plan, edition, Seat count and any plan limits, its issue and expiry dates, and the licensee name, email address, organisation and website held on your account. Like any web request, it also tells us the network address it came from.

Switch automatic renewal off in your Instance's configuration (the self-hosting guide shows how) and your Instance makes no licence calls to us at all; you then apply each renewed key yourself.

You are the controller of any personal data in your Instance. Because we neither receive nor process it, we are not your processor for it.

9. Updates and support

You are entitled to all updates we publish for the Software during your Term, including security updates. We may change how the Software works between versions.

A Self-host Team licence comes with best-effort email support at support@kythene.com. We'll answer as soon as we reasonably can, but we don't commit to a response time.

10. Intellectual property

We own the Software and everything in it. These terms grant you a licence to use it, and nothing more. You own everything you create with it.

11. Warranties

We warrant that we have the right to license the Software to you.

Otherwise the Software is provided as is. We do not warrant that it will be uninterrupted, error-free, or fit for a particular purpose, and we exclude all implied warranties as far as the law allows.

12. Liability

Nothing in these terms limits liability for death or personal injury caused by negligence, for fraud, or for anything else that cannot lawfully be limited.

Subject to that, neither of us is liable for indirect or consequential loss, loss of profit, loss of business, or loss of data, and our total liability in any twelve-month period is limited to the fees you paid us in that period.

13. Ending the licence

You may stop using the Software at any time.

We may terminate your licence if you materially breach these terms and do not fix it within 30 days of us telling you. On termination you must stop using the Software and destroy your copies, though you may keep and export your own data first - and we will give you a reasonable period to do so.

Sections 8, 10, 11, 12 and 14 survive termination.

14. General

Changes. We may update these terms. If a change materially reduces your rights, we will tell you before your next renewal, and you may cancel rather than accept it. Changes do not apply retrospectively to your current Term. On the free self-host tier, which has no Term and no renewal, a change applies from the date we publish it, and you may stop using the Software rather than accept it.

Assignment. You may not transfer these terms without our consent, which we will not unreasonably withhold. We may transfer them to a company that acquires our business.

Entire agreement. These terms are the whole agreement about the Software and replace anything said before.

Notices. Write to us at support@kythene.com, or by post to our registered office in section 1.

Governing law. These terms are governed by the law of England and Wales, and the courts of England and Wales have exclusive jurisdiction.

15. Free self-host

You may run the Software free of charge, without a licence key, for one person. This is the free self-host tier.

What you may do. We grant you a non-exclusive, non-transferable, worldwide licence to install and run the Software on infrastructure you control, for your own use or your own organisation's internal business use, and to make copies for backup, testing, staging and disaster recovery. The free tier has no Term, and the Software includes any updates we publish for as long as you use it.

One Seat. The free tier covers one Seat in total, counted as section 5 counts Seats, however many Instances you run. Guests and AI agents are free here too. Anyone beyond that one person needs a Self-host Team or Enterprise licence. Changing your Instance's seat setting (KYTHENE_FREE_SELFHOST_SEATS) does not change what this licence covers.

No fee, no support. There is nothing to pay and nothing renews. The free tier comes with no support.

No licence calls. With no licence key, your Instance makes no licence calls to us at all. The Software does not report your usage to us, and we do not audit your Instance.

What else applies. Sections 1, 2, 4, 8, 10, 11, 12, 13 and 14 apply to the free tier as they do to a Self-host Team licence, read with this section. Sections 3, 5 (other than how Seats are counted), 6, 7 and 9 do not.

Moving to a team. Apply a Self-host Team licence key to the same Instance and the Self-host Team sections of these terms govern it from then on. Your data stays where it is.