Terms of Service

Last updated 2026-08-31. Creating an API key or using the service means you accept these terms.

1. The service

Dierum provides calendar and date-calculation data via API, embeddable widgets, and web tools. Plans, limits, and prices are listed on the pricing page; limits are enforced per UTC day and over-limit requests are refused, not billed.

2. Accuracy and the limits of calendars

We source holiday data from maintained open datasets, cross-check it before release, and refuse requests outside our covered range rather than guess. Even so, governments change holidays on short notice and errors are possible. The service is provided "as is", without warranty of accuracy, completeness, or fitness for a particular purpose. For decisions with legal or financial consequence (contractual deadlines, regulatory filings, settlement obligations), verify critical dates against an authoritative source. You are responsible for how results are used.

3. Accounts and keys

Keys are issued to your email address, stored only as hashes, and are your responsibility to keep secret; server-side keys must not be exposed in client code (publishable keys exist for that). You are responsible for usage under your keys. We may revoke keys that are abused or compromised.

4. Acceptable use

Do not: use the service for unlawful purposes; attempt to probe, breach, or overload it beyond published limits; resell or redistribute the raw data feed wholesale as a competing dataset; misrepresent your identity to the service; or interfere with other customers' use. Fair, documented use of the free tiers is welcome; systematic evasion of limits (key farming, quota rotation) is not.

5. Payment, cancellation, refunds

Paid plans bill monthly through Stripe and renew until cancelled. Cancel any time; access continues to period end, then drops to the free tier. Over-limit usage is never charged. If we materially fail to provide the service in a billing period, contact us and we will make it right, up to and including a refund of that period.

6. Availability

We aim for high availability and publish status at /health, but no uptime level is guaranteed outside a written Enterprise agreement. Planned changes that break the API will be versioned or announced ahead of time.

7. Liability

To the maximum extent permitted by law, our total liability for any claims arising from the service is capped at the amount you paid us in the three months before the claim arose, and we are not liable for indirect, incidental, or consequential damages, including missed deadlines, lost profits, or losses from decisions based on returned data. Some jurisdictions limit such exclusions; where they do, these terms apply to the fullest extent permitted.

8. Widgets and embeds

Embedding widgets on your sites is licensed for use with a valid key (the demo widget excepted). Widgets on Free through Starter plans display attribution; removing it requires a Pro or higher plan. You are responsible for your own site's compliance toward its visitors.

9. Termination

You may stop using the service at any time. We may suspend or terminate access for breach of these terms, with notice where practical. Sections 2, 7, and 10 survive termination.

10. General

These terms are governed by the laws of the United States and the State of Texas, without regard to conflict-of-law rules. If a provision is unenforceable, the rest stand. We may update these terms; material changes will be dated here and, for paying customers, announced by email. Continued use after changes is acceptance. Contact: sales@dierum.io.