Privacy Policy

This Privacy Policy describes how Metronome.fm, a metronome app operated by Daijiro Yamauchi ("we", "our", "us"), handles personal information (the "Service").

By using the Service you agree to this policy.

We collect the following categories of information:

• Account information: When you sign in with Clerk we receive your Clerk user ID, display name, avatar URL and email address. We store the Clerk user ID, display name and avatar URL in our database (Postgres hosted by Supabase), along with any updates we get from Clerk. Your email address is kept by Clerk; we do not store it in our database.
• Metronome content: When you save or share metronome presets we store tempo ranges, track configurations (including progressive BPM settings, repeat counts and color choices), favorite flags and your visibility preferences. We also keep the last 10 presets you viewed and accumulate playback duration statistics in 10-second increments.
• Contact messages: If you submit the contact form we store your name, email, subject and message so we can reply.
• Subscription information: When you subscribe to Pro, we associate your Stripe customer ID and subscription status (such as whether you are on Pro and your next billing date) with your Clerk user ID. Payment details such as card numbers are received directly by Stripe; we do not store them.
• What we send to AI: For "Ask AI for the BPM", we send the text you enter to Google Gemini, together with an automatically generated search query, to get BPM candidates. For "Ask AI to edit settings", we send the text you enter and the content of your current metronome settings (such as tempo, time signature and track structure). If you ask AI after detecting the BPM from an audio file, the file name in the input field is also sent.
• Microphone, camera and audio files: Audio and video from your microphone and camera, used for recording and live BPM detection, and audio files you analyze for BPM are processed on your device and are not uploaded to our servers. Recordings are stored only on your device.
• Technical data: To enforce playback, AI, audio-analysis, export and recording limits, we record usage counts and your device time zone in Upstash Redis, keyed by your Clerk user ID, your IP address, or a random per-browser ID. Vercel Analytics collects pseudonymous device and usage metrics.
• Cookies and local storage: We set the NEXT_LOCALE cookie (1-year lifetime) to remember your language preference and rely on Clerk session cookies for authentication. To count playback time for visitors who are not signed in, opening the app stores a random per-browser ID in the mfm_guest_id cookie (1-year lifetime). We do not link this ID to any other information. To reset limits at midnight and on the 1st of each month, we store your device's time zone (such as Asia/Tokyo) in the mfm_tz cookie (1-year lifetime). In the browser we store volume, timer, drawer width and similar interface settings using localStorage.

We use the collected information to operate and improve the service, restore your presets, enforce fair use, surface practice statistics, respond to inquiries and protect the platform from abuse.

We do not sell personal data.

Service providers process data on our behalf:

• Clerk handles authentication, session cookies and user management.
• Supabase hosts our database (Postgres), which stores account information, saved presets, statistics and contact messages.
• Upstash Redis stores rate-limit counters keyed by Clerk ID or IP address for up to the configured window.
• Vercel hosts Metronome.fm and provides analytics that may collect device and request metadata.
• Google Gemini (with Google Search tools) processes the text you enter into AI features and, for setting edits, the content of your current settings, and returns the results.
• Stripe and Link (Sold through Link, LLC) handle Pro payments, billing, tax calculation, and subscription management.
• Resend sends your contact messages (name, email address, subject and message) to our support inbox.
• Better Stack stores error and activity logs (error details, page URL, browser type and identifiers such as your Clerk user ID) so we can investigate problems. As a rule, these logs do not include email addresses or contact messages.
• Cloudflare Turnstile checks your browser when you sign up through Clerk, to prevent automated sign-ups.

These providers operate under their own privacy terms while acting as processors for us.

Many of the providers above are located in the United States, and your personal data is mainly handled on servers in the United States (some providers, such as Supabase, Upstash and Vercel, may also handle it in other countries or regions).

These providers have, through their data processing agreements or terms, systems in place to continuously take measures equivalent to the obligations under Japan's Act on the Protection of Personal Information. We periodically check, through their terms and published information, that these systems are maintained.

Information about the personal information protection system of the United States is available in the survey of foreign personal information protection systems on the website of Japan's Personal Information Protection Commission. Information about the measures we take is available on request.

If you mark a metronome preset as public, your display name and avatar may appear to other users and inside dynamically generated open-graph images.

Only share presets publicly when you are comfortable publishing the associated information.

Metronome content remains until you delete it in the app. Favorites and histories update automatically as you interact with presets.

When you delete your account, we also delete your saved presets, favorites, history and statistics.

Contact messages are deleted one year after we receive them. If you delete your account, messages sent from that account are deleted at that time. Rate-limit counters expire automatically after their configured window.

You can delete presets and histories from the app, and you may request additional deletion or export by contacting us.

We take the following measures to prevent leaks and other incidents involving personal data:

• Organizational and personnel measures: Only the operator handles personal data, and how it is handled is set out in this policy and our operating procedures.
• Technical measures: Communications are encrypted (HTTPS), and row-level access control is enabled in the database so it cannot be read or written directly with external keys. Databases and API keys are separated between production and development, and secrets are managed as hosting environment variables.
• Understanding the external environment: We take security measures with an understanding of the personal information protection systems of the countries where personal data is handled (mainly the United States).

Further details are available on request, to the extent that disclosure does not interfere with security.

You may ask us to notify you of the purposes of use, to disclose (including records of provision to third parties), correct, add to or delete, to stop using or erase, or to stop providing to third parties the personal data we hold about you.

Please send requests through the in-app contact form or to support@metronome.fm. We will respond without undue delay after confirming your identity, for example with the email address of your signed-in account. There is no fee.

If you are in the European Economic Area (EEA) or the United Kingdom, the following also applies under the GDPR and the UK GDPR.

• Controller: Daijiro Yamauchi, the operator of Metronome.fm, is the controller of your personal data. You can contact us through the in-app contact form or at support@metronome.fm.
• Legal bases: We process your data to provide the Service you request, including your account, saved presets and Pro subscription (performance of a contract); to keep the Service secure, enforce usage limits, investigate errors and understand usage in a pseudonymous way (our legitimate interests); and to keep payment and tax records as required by law (legal obligation).
• Cookies: The cookies we set (language, sign-in session, the random per-browser ID used for usage limits and your time zone) are necessary to provide the Service. We do not use advertising cookies, and Vercel Analytics does not use cookies.
• International transfers: Your data is transferred to Japan, where we operate, and to the United States and other countries where our providers process it. Japan is covered by an adequacy decision of the European Commission and adequacy regulations of the UK. For transfers to the United States and other countries, we rely on the safeguards in our providers' data processing terms, such as the Standard Contractual Clauses or the EU-U.S. Data Privacy Framework.
• Retention: We keep your data for the periods described in "Retention and Deletion" above, and delete it when it is no longer needed.
• Your rights: You have the right to access, rectify or erase your data, to restrict or object to processing, and to data portability. Where processing is based on consent, you may withdraw it at any time. To exercise these rights, contact us as described in "Your Requests".
• Complaints: You have the right to lodge a complaint with the data protection authority in the country where you live or work, or, in the United Kingdom, the Information Commissioner's Office.
• Automated decisions: We do not make decisions that produce legal or similarly significant effects on you based solely on automated processing.

You may browse as a guest with limited functionality or sign in to unlock full features.

You can delete or unpublish presets, sign out or delete your account at any time. You can clear data stored in your browser through your browser settings.

The service is not directed to children under 13 and we do not knowingly collect their information.

We will update this policy and publish the changes on this page when our practices change.

Business handling personal information: Daijiro Yamauchi. Our address will be provided without delay upon request.

For questions or complaints about how we handle personal information, please use the in-app contact form or email support@metronome.fm.