Privacy notice
Last updated: 15 August 2026
This notice explains what personal data we process when you use the CRAYON-C4 service, why we process it, who helps us do it, and what rights you have. It covers the hosted service at crayon-c4.com. It does not cover an instance you run on your own infrastructure — there the operator of that instance is the controller, not us.
1. Who is responsible
The controller of your personal data is:
- Legal entity
- SQUORA
- Registered address
- W.F. Hermansstraat 526, 3544 KP Utrecht, The Netherlands
- Chamber of Commerce (KvK)
- 42105674
- VAT number
- NL001924069B86
For anything in this notice, reach us through the support page. We have not appointed a data protection officer; we are not required to.
2. What we process, and why
| Data | Why | Legal basis |
|---|---|---|
| Email address, name and avatar from the identity provider you sign in with, and which provider that was | To create and identify your account, to email you about your account, and to let collaborators see who you are | Performance of our contract with you |
| Your projects — models, diagrams, decisions and the text in them — and the project members and invitations you create | To provide the Service: to store your work and show it back to you | Performance of our contract with you |
| Subscription status, billing period, Stripe customer and subscription identifiers | To give you the plan you paid for and to handle renewals and failures | Performance of our contract; legal obligation for tax records |
| An audit record of significant project actions (who invited, removed, published or restored, and when) | So a project owner can see what happened to a shared project, and to investigate abuse | Our legitimate interest in a secure, accountable service |
| Aggregate usage measurement: page views, page performance, and counts of product events such as “a project was created” | To decide what to build and what to fix | Our legitimate interest in improving the Service |
| Anything you write to us through the support or feedback form | To answer you | Performance of our contract; our legitimate interest in support |
We do not sell your data, and we do not advertise. We do not use the content of your projects to train machine-learning models. Our usage measurement is cookieless and is not used to build a profile of you, which is why the site shows no cookie banner.
3. Who processes it with us
We use a small number of providers to run the Service. Each processes personal data only on our instructions, under a data processing agreement.
| Provider | What for | Where |
|---|---|---|
| Auth0 (Okta, Inc.) | Sign-in and identity | EU / United States |
| Neon, Inc. | The database holding your account and your projects | European Union (Frankfurt) |
| Vercel, Inc. | Hosting, content delivery, and the usage and performance measurement | EU / United States |
| Stripe, Inc. / Stripe Payments Europe | Payments, invoices and VAT determination | EU / United States |
| Our mail host | Sending account and invitation email | European Union |
Two things load in your browser directly from third parties, which means those services see your IP address and the request: Iconify (the icons drawn on diagram elements) and, only on the video page in our documentation, YouTube thumbnail images. Neither receives any of your project content.
Card details go straight to Stripe from the payment page. We never receive or store them.
4. Transfers outside the EU
Some of the providers above are established in the United States. Where a provider is certified under the EU–U.S. Data Privacy Framework we rely on the European Commission’s adequacy decision; otherwise we rely on the Commission’s standard contractual clauses, together with the provider’s technical measures. You can ask us for details of the safeguards in place.
5. How long we keep it
| What | Kept |
|---|---|
| Your account and your projects | Until you delete them, or you delete your account |
| Project version snapshots | A short rolling window only — roughly the last 100 saves, and not more than about 30 days. Version history is a convenience, never a backup |
| Invitations | Until accepted, declined, revoked, or expired (12 days) |
| Invoices and payment records | Seven years, as Dutch tax law requires |
| Support and feedback correspondence | As long as needed to handle it, and a reasonable period afterwards |
Deleting your account removes your personal data and the projects you own. It cannot be undone, and we cannot recover deleted content for you — export first. Payment records are kept for the statutory period regardless, because we are required to keep them.
6. Your rights
You have the right to:
- ask what personal data we hold about you, and get a copy;
- have inaccurate data corrected;
- have your data erased;
- restrict or object to processing based on our legitimate interests;
- receive the data you gave us in a portable format — for your projects you can do this yourself at any time, on any plan, with the built-in JSON export;
- withdraw consent, where we relied on it.
Ask through the support page. We answer within one month. If you are not satisfied you can complain to the Dutch data protection authority, the Autoriteit Persoonsgegevens, or to the authority where you live.
7. Security
Traffic is encrypted in transit. Access to production systems is limited to people who need it. We do not store passwords: sign-in is delegated to your identity provider. No service can promise perfect security, and you remain responsible for keeping independent copies of your work — see the disclaimer.
8. Sharing you control
When you invite someone to a project, they see the project and the name and email on your account. When you publish a read-only link, anyone holding that link can read that project without an account — the link is the whole permission. You can revoke a published link at any time, and revoking deletes it rather than disabling it.
9. Changes to this notice
We may update this notice. The date at the top reflects the latest revision, and we will tell account holders by email about a change that materially affects them.
10. Related documents
- Terms of Service — plans, billing, cancellation and your rights as a customer.
- Disclaimer — warranty, your backups, retention and limitation of liability.