Terms of Service

Version 2026-10-24 (draft, pending founder review). Chinese version: 服務條款. If the two versions differ, the Chinese version prevails.

These terms set out your rights and responsibilities, and ours, when you use Synhedra (the "Service", provided by Synhedra, "we" or "us"). By using the Service you agree to these terms. How we handle personal data is described in the Privacy Notice; where the two differ on personal data, the Privacy Notice prevails.

1. What the Service is

• The Service is a beta: it runs in your browser for early-stage building massing, 2D drawings, and preliminary code and structural checks. Features, interface and limits change as we develop it and may be added, changed or removed.
• The Service is currently free. If we introduce paid plans we will announce them in advance, and we will not put content you created for free behind a paywall to get it back.
• There is no service level agreement (SLA). The Service may pause or slow down for maintenance, faults, third-party outages or usage caps. We do our best to fix problems but do not guarantee availability or that data is never lost. Export important designs yourself (.lsm, DXF, IFC and so on).

2. Accounts

• Most features work without signing in; your designs stay in your own browser. AI, cloud storage, sharing and live collaboration require Google sign-in (or an invite code).
• When you sign in we receive only the account identifier Google provides; we do not store your email, name or avatar. See the Privacy Notice for details.
• You are responsible for your Google account and invite code. Do not pass invite codes to people you do not know. Contact us promptly if someone else is using your account.

3. Your content

• Designs, drawings, site data, text and files you create or upload ("your content") remain yours (or the original rights holder's). We claim no ownership.
• To run the Service you allow us, to the extent necessary, to store, copy, convert, transmit and display your content — for example saving it to the cloud, generating thumbnails and preview images, showing it to link holders according to your sharing settings, and forwarding what you submit to an AI provider for processing. This licence is only for providing the Service; it does not cover advertising, selling your content, or publishing it when you have not shared it.
• The licence ends when you delete the content or your account, except for what you already shared and others already copied or downloaded, which we cannot recall.
• You must have the right to use what you upload (for example cadastral maps, other people's drawings or photos) without infringing anyone's copyright, trademark or other rights.

4. AI features

• When you use an AI feature (AI interpretation, AI canvas, AI assistant, AI layout, design statements and similar), the text you enter, images you upload and the necessary design summary (such as floor outlines, area figures and cleaned-up names) are forwarded through our server to the AI provider configured on the server. We do not send your account data to the provider. What each AI feature sends is listed on screen before sending and in the "AI features" section of the Privacy Notice.
• The current AI provider is Google Gemini (set by the server; this may change or other providers may be added; every response states the provider and model actually used). The provider handles this data under its own terms and privacy policy.
• The Service currently uses the unpaid tier of the Gemini API. Under Google's terms, content sent to the unpaid tier may be used by Google to improve its products and may be reviewed by humans. Do not enter personal data, confidential information or anything you would not want a third party to see.
• AI output may be wrong, incomplete or non-compliant. Layouts, figures and text produced by AI are suggestions only; check them and decide for yourself whether to use them.
• AI features have daily and monthly usage caps. When a cap is reached the feature is unavailable until the next day or month.

5. What you must not do

When using the Service, do not:

• break the law or infringe anyone's intellectual property, privacy or other rights;
• upload malware, attempt intrusion, scan for vulnerabilities, or bypass sign-in, quotas, rate limits or other safeguards;
• call the API in bulk by automated means, scrape content, or otherwise put unreasonable load on the servers;
• use share links, parameter pages or collaboration rooms to spread illegal, harassing, fraudulent or misleading content, or impersonate others;
• use the AI features to generate content that breaks the provider's usage policies;
• resell or rent out the Service, or publish invite codes.

If you break these rules we may remove the content, disable share links, or suspend or close your account, and in serious cases cooperate with the authorities.

6. Disclaimer

• The Service's code checks (floor area ratio, coverage, height, parking, accessibility, green building and so on) and structural analysis (preliminary column and beam sizing, frame analysis, seismic forces and so on) are preliminary estimates computed from your inputs with simplified models, for design exploration and discussion only.
• These results are not a certification or review by an architect, engineer or other licensed professional and do not replace review by the authorities. For permit applications, construction or any decision that relies on them, have a qualified professional verify them against current regulations and complete information.
• Base maps, surrounding buildings, address lookup and similar data come from third parties (see Data sources and methods) and may be inaccurate or out of date.
• To the extent permitted by law the Service is provided "as is", and we are not liable for losses caused by using or being unable to use the Service, data loss, or incorrect results. This does not exclude liability that cannot be excluded by law.

7. Changes, termination and data deletion

• You may stop using the Service at any time. When signed in, the account menu offers "Download my data" and "Delete account"; deleting your account also deletes your cloud designs (including recently deleted ones), collaboration rooms and folder-share records; design share links and parameter pages you created are kept (you can still manage or stop them from the original browser) but are no longer linked to your account.
• Cloud designs you delete can be restored from "Recently deleted" in the account panel for 30 days, after which a scheduled job deletes the content; you can also delete them permanently from "Recently deleted".
• Accounts unused for 365 consecutive days are deleted automatically together with their cloud data.
• We may change or discontinue all or part of the Service for operational reasons. Before discontinuing the whole Service we will post a notice on the site and allow a reasonable period for you to export your designs.
• When these terms change we update the version date at the top of this page; significant changes are also announced on the site. Continuing to use the Service after a change means you accept the new terms.

8. Governing law and jurisdiction

Governing law: (to be filled in by the founder). Disputes arising from these terms are subject to the jurisdiction of (to be filled in by the founder) as the court of first instance.

9. Contact

Questions about these terms: (to be filled in), (to be filled in).