The deal, in plain words.
Last updated 6 September 2026
These terms cover your use of MermaidStage. They are written to be specific rather than to sound thorough.
What the service does
MermaidStage turns a Mermaid architecture diagram into a narrated 3D tour you can play, pause and explore. It is in development, and the site says so. Features described as planned are not promises with dates attached.
Narration is either your browser’s own speech synthesis, which differs by machine and by browser, or generated audio on paid plans, which is recorded once and plays the same for every viewer. A shared Stage without generated audio plays in the viewer’s own browser voice.
Your account
You are responsible for what happens under your account and for keeping your password to yourself. Tell us promptly if you think someone else has it. One person, one account — do not share credentials.
What you may not do
- Upload content you have no right to upload.
- Attempt to reach another workspace’s data.
- Resell the service as your own.
- Deliberately overload it, or use it to attack anyone.
Paying, and what a payment buys
- Free — one person, two Stages, the full 3D player, browser narration.
- Individual — $9 per month or $84 per year. One person, unlimited Stages.
- Team — $19 per editor per month or $156 per editor per year. Readers are free and unlimited.
- Enterprise — annual, 25 editors minimum, priced per agreement.
You pay for editors, the people who can build. Readers can only watch and are never charged. A pending invitation holds an editor seat so that nobody is invited and then turned away, but it is not billed until they accept. Editors are counted continuously: add people and the charge follows, prorated at the time of the change rather than as a surprise at renewal.
What happens if you stop paying
We never delete your colleagues. If a subscription lapses, your workspace drops to Free and every member stays exactly where they are. You will be over the seat limit, which means you cannot invite anybody new until you are back under it. Nothing else stops working, and nothing is erased.
If a card is declined, access continues while Stripe retries. We will email you rather than let it fail silently.
Refunds
If it is not doing what you hoped, tell us within 30 days of a charge and we will refund it. We would rather return the money than argue about a subscription somebody is not getting value from.
Who owns what
Your diagrams and tours are yours. You keep every right you had in them. You give us only the permission needed to store them and show them back to you and the people you share them with. We do not use them to train models.
The software, the renderer and the brand are ours.
Availability
We aim to keep it up and are not promising a particular uptime figure while it is in development. Saved versions are immutable, so a change or a regeneration never rewrites a presentation somebody has already reviewed.
Limits on liability
The service is provided as it is. To the extent the law allows, our total liability is limited to what you paid us in the twelve months before the claim. Nothing here excludes liability that cannot lawfully be excluded.
A diagram is a description of a system, not a guarantee about it. Do not rely on a generated tour as a security review.
Ending it
Cancel whenever you like — the plan runs to the end of the period you have paid for. Ask us to delete your account and we will remove your workspace and everything in it. We may suspend an account that is breaking these terms, and we will tell you why.
Changes
If these terms change materially we will say so in the product rather than quietly editing the date.
Questions about any of this: support@mermaidstage.com.