Terms, privacy and refunds
Last updated: October 22, 2026
Terms of use
c4nta (c4nta.com) is a web app for practicing pitch and training your ear by singing into your microphone. By using it you agree to these terms.
Free version
You can use c4nta without signing up and without paying. The free version may have a daily practice time limit, which is shown in the app and resets every day.
c4nta Pro
- c4nta Pro is a monthly or yearly subscription that removes the daily practice limit.
- The price is shown in your currency before you pay. The amount on the payment screen is the total you are charged.
- Payments are processed by Stripe. We never see or store your card details.
- Your subscription renews automatically at the end of each period, at the same price, until you cancel it.
- Pro is tied to the email you paid with. To turn it on in another browser or device, use “Already paid on another device?” in the app.
- If we ever change the price, we will email you before your next renewal; the period you already paid for doesn't change.
Acceptable use
Don't try to break, overload or copy the service, or resell access to Pro. We may suspend access for anyone who does.
Your voice
c4nta is a practice tool and does not replace a singing teacher or a health professional. If you feel pain, hoarseness or fatigue while singing, stop and rest.
Availability and liability
We do our best to keep c4nta working well, but it is provided “as is”, without guarantees that it will be error-free or always available. We may improve, change or remove exercises. To the extent the law allows, our total liability is limited to what you paid for Pro in the last 12 months.
Intellectual property
The code, design, text and the c4nta brand belong to us. Practice songs belong to their authors.
Governing law
These terms are governed by the laws of Mexico. If you are a consumer in another country, you keep any rights your local law gives you.
Cancellation and refunds
- Cancel anytime from “Manage subscription” in the app, or by emailing us. No commitment, no fees.
- When you cancel, you keep Pro until the end of the period you already paid for, and you are not charged again.
- 14-day refund: if Pro isn't for you, email support@c4nta.com within 14 days of any charge and we will refund that charge in full, no questions asked. The refund goes back to the same payment method, usually within 5–10 business days.
- After those 14 days we don't give partial refunds for the current period.
Privacy policy
c4nta (c4nta.com) is responsible for your data. You can reach us at support@c4nta.com. We collect the minimum needed to run the app and to charge for Pro. We don't sell your data or show ads.
Your microphone
Microphone audio is analyzed inside your browser to detect the note you sing. It is never recorded or sent to any server.
What is stored on your device
There are no accounts. Your settings, your progress, today's practice minutes, the date of your first visit and, if you are Pro, a signed credential (with your Stripe customer ID and expiry date) are kept in your browser's local storage. You can delete them anytime by clearing the site's data.
Payments
If you subscribe to Pro, Stripe receives your email, payment details and country to charge you, send receipts and prevent fraud. We receive your email, country and subscription status from Stripe and use them to turn on Pro, restore it on another device and handle your requests. Stripe handles your data under its privacy policy. Payment records are kept as long as tax law requires.
Analytics
We use Cloudflare Web Analytics, which uses no cookies and doesn't track individuals: it counts visits per page, country, browser, device type and referring site. We also anonymously log steps of the Pro flow (for example, “opened the Pro screen”) along with country, language and time, without any personal identifier. To learn how much people practice, each day we log your browser's practice minutes under a random code that changes daily (it can't recognize you from one day to the next), along with country, language, the site you came from and how many days have passed since your first visit.
Third-party services
- Cloudflare hosts the site and processes your IP address to deliver the pages.
- GitHub Pages (tonejs.github.io and gleitz.github.io) serves the piano sounds, so it receives your IP address when they download.
- giscus / GitHub loads the Community section only when you open it. To comment you sign in to GitHub, which handles that data under its own policy.
Your rights
You can ask us to access, correct or delete your data, or object to its use (including your rights under the GDPR if you are in the European Union), by emailing support@c4nta.com. We reply within 20 business days at most.
Minors
To subscribe to Pro you must be an adult or have permission from a parent or guardian.
Changes
If we change this policy in a meaningful way, we will say so on this page with a new “last updated” date.
Contact
Questions, support, cancellations or refunds: support@c4nta.com. We usually reply within one or two business days.