PhoneKit

Marvium

Privacy Policy

Last updated: September 12, 2026

Marvium is a local-first Markdown reader and notes app. The app does not require an account. Most app content stays on your device, including Markdown files, collections, notes, reading progress, app settings, and optional AI API keys. Some features involve third-party services, as described below.

Data You Store In The App

Marvium stores the following data locally on your device:

  • Markdown file names and Markdown content.
  • Collections, nested collections, sort order, and favorites.
  • Table of contents, completed headings, and reading position.
  • Notes attached to selected text or sections.
  • Cached AI summaries created for Markdown files.
  • AI usage records such as provider, model, request type, token counts, file count, and response time. Prompts and generated text are not stored in these usage records.
  • Downloaded on-device AI models and their context and generation settings.
  • Settings such as theme, language, font size, code highlight theme, autosave, feedback, swipe, performance, and reopen-last-file choices.
  • Ad eligibility counters, including active usage time and file-open counts.
  • Optional OpenAI, Anthropic, and Google Gemini API keys. These are stored in secure device storage where supported.

Files, Imports, And Sharing

When you pick files from your device, Marvium reads the selected files so it can import or convert them. Supported import/conversion files include Markdown, text, HTML, JSON, CSV, TSV, XML, YAML, logs, RTF, Word documents, PDFs, and images. The app limits multi-file AI conversion to 5 files, 10 MB per file, and 20 MB total.

If you import from a URL, your device requests that URL and downloads readable Markdown, text, or HTML content. The website you request may receive ordinary network information from your device, such as IP address, user agent, and request time.

If you use a share or export feature, Marvium sends the content or file you selected—including Markdown, PDF, DOCX, or backup files—to the operating system share sheet. The app you choose from the share sheet handles that content under its own policy.

AI Features

AI features are optional. Cloud AI features require your own API key, which is sent to the selected provider to authenticate your request. Depending on the action you choose, Marvium may send prompts, selected Markdown content, extracted file text, images, PDFs, Word files, or other selected file data to OpenAI, Anthropic, or Google Gemini. AI features include summarizing, rewriting, taking notes, converting web pages, and creating Markdown from selected files.

On-device AI runs locally and does not send your prompts or document content to an AI provider. If you download a model from Hugging Face, your device contacts Hugging Face to retrieve the model file and may share ordinary network information such as your IP address, user agent, and request time. Downloaded model files remain on your device until you remove them or uninstall the app.

AI providers process requests under their own terms and privacy policies. Do not use AI features with private or sensitive content unless you are comfortable sending that content to the selected provider.

Analytics And Crash Reporting

Marvium uses Firebase Analytics and Firebase Crashlytics to understand app usage, improve product quality, and diagnose crashes. We may collect app usage and diagnostic data, such as app opens and screen views; feature usage, such as import, export, search, notes, collections, appearance settings, and AI actions; app version, device type, operating system version, locale, and crash diagnostics; broad AI action metadata, such as action type and selected provider; and service-generated identifiers such as Firebase installation or Crashlytics installation identifiers.

We do not send Markdown file contents, file names, note text, URLs entered by the user, local file paths, AI API keys, or selected text from documents as analytics events.

Crash reports may include technical diagnostic information needed to identify and fix app stability issues. Analytics and crash data are processed by Google Firebase and Google Analytics according to Google's terms and privacy practices.

Ads

Marvium uses Google Mobile Ads to show rewarded ads after eligibility thresholds are met. Google Mobile Ads may collect or process device identifiers, advertising identifiers, IP address, app activity, approximate location inferred from network data, ad interactions, diagnostics, and other information needed for ad delivery, measurement, fraud prevention, and compliance.

Where legally required, Google or the app may request consent for advertising-related data use. You can also manage advertising choices through your device settings and applicable Google controls.

Subscriptions

Marvium uses RevenueCat to offer and manage Marvium Pro subscriptions. RevenueCat and the applicable app store may process an anonymous app user identifier, purchase history, subscription status, product and entitlement information, locale, app and device information, and data needed to validate purchases, restore access, prevent fraud, and provide subscription analytics. Marvium does not send RevenueCat your Markdown content, notes, or AI API keys.

Support, Reviews, And External Links

Marvium can open GitHub issue forms for bug reports, feature requests, improvements, and feedback. If you submit an issue, GitHub receives the information you provide, such as your description, device details, screenshots, logs, or contact information. Do not include private Markdown files, notes, or AI API keys in public issues.

The app can request an App Store review through the operating system review prompt. It can also open external links from Markdown documents in your browser or another app.

If you search selected document text with Google, that selected text is included in the Google search URL opened by your browser. Markdown previews and document exports may also request remote images referenced by a document. Google and remote image hosts receive the request and ordinary network information such as your IP address, user agent, and request time.

What We Do Not Do

  • Marvium does not require a PhoneKit account.
  • Marvium does not operate its own cloud sync service.
  • Marvium does not sell your Markdown files, notes, or API keys.
  • Marvium does not send your local content to AI providers unless you choose an AI action.

Third-Party Services

Marvium may integrate with these third-party services:

  • Firebase Analytics and Firebase Crashlytics for app usage analytics and crash diagnostics.
  • Google Mobile Ads for advertising and ad measurement.
  • OpenAI, Anthropic, and Google Gemini for optional cloud AI requests.
  • Hugging Face for optional on-device AI model downloads.
  • RevenueCat and Apple or Google app stores for subscriptions, purchase validation, and entitlement management.
  • GitHub for public issue reporting and feedback.
  • Apple or Google platform services for file picking, sharing, reviews, and app distribution.

Third-party services are expected to protect user data consistently with their own published terms and privacy commitments. Their independent processing is governed by their own policies.

Retention And Deletion

Local app data remains on your device until you delete it in the app, clear the relevant setting, or uninstall the app. You can remove files, notes, summaries, collections, API keys, and settings from the app where those controls are available. Uninstalling the app removes app-local data according to the operating system's normal behavior.

Data sent to third-party services, such as AI providers, Google, Firebase, RevenueCat, GitHub, Apple, or external websites, is retained according to those services' policies. Contact those providers directly for their deletion processes where applicable.

Children

Marvium is not directed to children under 13, and we do not knowingly collect personal information from children. If you believe a child provided personal information through support or issue reporting, contact us so we can review the request.

Security

Marvium uses platform storage and secure storage APIs where appropriate. No app or transmission method can be guaranteed completely secure, so keep backups of important files and avoid placing secrets in public issue reports.

Changes

We may update this policy when the app, third-party services, or legal requirements change. The updated date will show when the policy was last changed.

Contact

For privacy questions, email support@phonekit.app.