Privacy Policy

Effective date: February 24, 2026 · Last updated: February 24, 2026

1. Introduction

MarkDeck ("we", "our", "us") is developed by Json, an individual developer. We are committed to protecting your privacy. This Privacy Policy explains what information we collect, how we use it, and what choices you have when you use the MarkDeck application ("App") on any platform (Android, iOS, Web, macOS, Windows, Linux) and the MarkDeck website at https://markdeck.dev.

By using the App or website, you agree to the collection and use of information as described in this policy. If you do not agree, please do not use the App.

2. Information We Collect

2.1 Information You Provide Voluntarily

MarkDeck does not require account creation. We do not collect your name, email address, or personal information through the App itself.

If you contact us via the contact form on our website (powered by Formspree), we receive the email address and message you voluntarily submit. This information is used solely to respond to your inquiry.

2.2 Information Collected Automatically

When you use the App, the following data is collected automatically through third-party services:

a) Analytics Data (Firebase Analytics)

We collect anonymous usage events to understand how the App is used and improve it. These events include:

file_opened — a file was opened (no file content or name is collected)
theme_changed, reading_theme_changed, font_changed — UI preferences were changed
toc_opened — the table of contents was opened
file_shared — a file was shared
onboarding_completed — the onboarding flow was completed

These events do not contain personal information, file contents, or filenames. Firebase Analytics may also collect device type, operating system, app version, country, and language.

b) Crash Reports (Firebase Crashlytics)

When the App crashes, we automatically collect crash reports including:

Device model and manufacturer
Operating system version
App version
Stack traces and error logs
Crashlytics installation UUID (anonymous)

This data helps us identify and fix bugs. No personal information or file contents are included in crash reports.

c) Advertising Data (Google AdMob)

The App displays banner advertisements served by Google AdMob. Depending on your consent and region, AdMob may collect:

Device advertising identifier (Ad ID / IDFA)
IP address (for geographic ad targeting)
Device and app information

2.3 Information We Do NOT Collect

File contents or filenames — your Markdown files are never uploaded or accessed by our servers
Location data (GPS)
Contacts, photos, or other device data
Browsing history
Biometric data

3. Your Files

MarkDeck does not upload, store, or access the content of your Markdown files on any server. All file processing happens entirely on your device. We have no ability to read, access, or recover your files. Your documents are yours.

4. How We Use Information

We use the collected information for the following purposes:

Improve the App: Analytics data helps us understand which features are used and how to improve the user experience.
Fix bugs: Crash reports allow us to identify and resolve issues quickly.
Display advertisements: AdMob serves ads to support the free version of the App.
Respond to inquiries: Contact form submissions are used solely to respond to your message.

5. Third-Party Services

The App uses the following third-party services, each with their own privacy policies:

Service	Purpose	Privacy Policy
Google AdMob	Advertising	Google Privacy Policy
Firebase Analytics	Usage analytics	Firebase Privacy
Firebase Crashlytics	Crash reporting	Firebase Privacy
Formspree	Website contact form	Formspree Privacy

We do not sell, trade, or share your data with any third parties beyond those listed above.

6. Advertising & Consent

MarkDeck displays a banner ad on the home screen, served by Google AdMob. We use Google's User Messaging Platform (UMP) to request your consent before serving personalized ads, in compliance with GDPR and other regulations.

Personalized ads: Shown only if you consent. These use your advertising ID and browsing behavior to show relevant ads.
Non-personalized ads: Shown if you decline personalized ads. These are contextual and do not use your advertising ID for targeting.

How to opt out

In-app consent: When the UMP consent dialog appears, choose your preference. You can change this at any time in the App settings.
Android: Settings → Google → Ads → Opt out of Ads Personalization
iOS: Settings → Privacy & Security → Tracking → disable "Allow Apps to Request to Track"
Reset advertising ID: You can reset your device's advertising identifier at any time through your device settings.

7. Data Retention

Firebase Analytics data: Retained for up to 14 months, then automatically deleted.
Firebase Crashlytics data: Retained for up to 90 days.
AdMob advertising data: Managed by Google according to their retention policies.
Contact form data: Retained only as long as necessary to respond to your inquiry.

8. Data Security

We take reasonable measures to protect your data. All data transmitted to third-party services (Firebase, AdMob) is encrypted in transit using TLS/SSL. However, no method of electronic transmission or storage is 100% secure, and we cannot guarantee absolute security.

9. Children's Privacy (COPPA)

MarkDeck is not directed to children under the age of 13 (or under 16 in the European Economic Area). We do not knowingly collect personal information from children. If you are a parent or guardian and believe your child has provided us with personal information, please contact us at [email protected] and we will promptly delete such information.

10. Your Privacy Rights

10.1 European Economic Area (GDPR)

If you are located in the European Economic Area (EEA), you have the following rights under the General Data Protection Regulation (GDPR):

Right of access: Request a copy of the data we hold about you.
Right to rectification: Request correction of inaccurate data.
Right to erasure: Request deletion of your data ("right to be forgotten").
Right to restrict processing: Request that we limit how we use your data.
Right to data portability: Request your data in a structured, machine-readable format.
Right to object: Object to data processing based on legitimate interests.
Right to withdraw consent: Withdraw consent for personalized advertising at any time via the UMP consent dialog or device settings.

Our legal basis for processing is: (a) your consent (for personalized advertising), and (b) legitimate interest (for analytics and crash reporting to improve the App).

To exercise these rights, contact us at [email protected]. We will respond within 30 days.

10.2 California Residents (CCPA / CPRA)

If you are a California resident, you have the following rights under the California Consumer Privacy Act (CCPA) and the California Privacy Rights Act (CPRA):

Right to know: Request what personal information we collect, use, and disclose.
Right to delete: Request deletion of your personal information.
Right to opt out of sale: We do not sell your personal information.
Right to non-discrimination: We will not discriminate against you for exercising your rights.

To exercise these rights, contact us at [email protected].

10.3 All Users

Regardless of your location, you may:

Request deletion of any data associated with your device.
Reset your advertising identifier through your device settings.
Opt out of personalized advertising via the in-app consent dialog or device settings.
Uninstall the App at any time to stop all future data collection.

11. International Data Transfers

Data collected through Firebase and AdMob may be transferred to and processed in the United States or other countries where Google operates. Google complies with applicable data transfer frameworks. By using the App, you consent to such transfers.

12. Changes to This Policy

We may update this Privacy Policy from time to time. Changes will be posted on this page with an updated "Last updated" date. For material changes, we may also notify you through the App. Continued use of the App after changes constitutes acceptance of the revised policy.

13. Contact Us

If you have questions, concerns, or requests regarding this Privacy Policy or your data, contact us:

Email: [email protected]
Website: https://markdeck.dev
Developer: Json