Privacy Policy
Effective date: July 14, 2026
Chalk: Construction Calculator ("Chalk") is made by Lionary LLC ("we", "us"). This policy explains what information the Chalk iOS app handles and how.
- Chalk has no accounts and collects no personal data — no name, no email, no location.
- Your projects, calculations, and settings are stored locally on your device. We can't see them.
- We collect anonymous usage analytics to improve the app. We do not use the IDFA, do not track you across other companies' apps, and never show the App Tracking Transparency prompt — because there's nothing to ask about.
- We never sell data and we don't show third-party ads.
Your projects and calculations
Saved projects, calculation history, measurements, and settings (like your fraction precision) are stored only on your iPhone. Chalk has no accounts and no cloud database — nothing you type into the calculators is uploaded to us. Every calculator works fully offline. Deleting a project or the app removes that data from the device. Chalk's data is included in your normal iPhone backups, which is how it moves to a new phone.
AI Advisor
The AI Advisor is the one feature that uses the internet. When you send a message to the Advisor, that message — and any saved project you explicitly attach to it — is sent to Google's Gemini model through Firebase AI Logic to generate a reply. We use Firebase App Check (App Attest) so only the genuine Chalk app can make these requests. Your chat history is stored only on your device. We do not attach your projects to the Advisor automatically — a project is only shared when you choose to attach it. The calculators never use this connection. If you don't use the AI Advisor, nothing you do in Chalk leaves your device except the anonymous analytics described below. Data sent to the Advisor is handled under Google's Firebase privacy terms.
Analytics
We use Mixpanel to understand how the app is used in aggregate (for example: that a stairs calculation was completed or a project was saved) and AppsFlyer to measure which of our ads or links brought new users to the app. This data is tied to a random per-install identifier — not your name, email, or any account. We do not use Apple's advertising identifier (IDFA) and we do not track you across apps or websites owned by other companies, which is why Chalk never shows the App Tracking Transparency prompt. Analytics never include your measurements, project names, calculation contents, or anything you type into the AI Advisor — only that an event (such as an advisor message being sent) happened.
Purchases
Subscriptions are processed by Apple. We use RevenueCat to validate receipts and manage subscription status. These services receive anonymized purchase and device information required to provide their function (such as a random app user ID and purchase receipts). We never see your payment details.
Data retention & deletion
Local data lives on your device until you delete it. Analytics data is retained by Mixpanel and AppsFlyer per our configuration. To request deletion of analytics data associated with your device, contact us at the address below.
Children
Chalk is a professional tool and is not directed at children under 13. We do not knowingly collect information from children.
Changes
We'll update this page when the policy changes and adjust the date above.
Contact
Questions or requests: support@chalkcalc.com