Privacy Policy

Controller

Tensfeldt Consultancy and Advisory LTD, bul. "Vitosha" № 25, 1000 Sofia, Bulgaria — contact: info@blitzkurs.com

What Blitzkurs stores on your device

Your streak, accuracy, round count, mute preference, and (optionally) the name you enter for the leaderboard are stored locally in your browser via localStorage. This data never leaves your device unless you explicitly submit a leaderboard entry (see below). It is not accessible to us and isn't transmitted anywhere.

Live price data

Bitcoin/Ethereum/Solana prices are streamed directly from Binance's public WebSocket API to your browser. In the Scalping Mode, the Trading Duel in Fight Mode and the Daily Challenge, your browser also requests candle chart data and reference prices from Binance's public REST API. Your device connects to Binance directly; no price data passes through our servers. As with any connection, Binance receives your IP address and browser information. We do not send any account, name or other personal data to Binance.

Fonts

The fonts used on this site (Space Grotesk and JetBrains Mono) are hosted on our own servers and delivered together with the site. Your browser does not connect to Google or any other third-party font provider to load them, so no data is transmitted to such providers for this purpose.

Leaderboard (optional, shared)

If you choose to submit a name after a new best streak, that name and score are sent to our database provider (Supabase) and displayed publicly to all visitors on the leaderboard. Don't submit a name you wouldn't want shown publicly. You can skip this at any time — it's entirely optional and never required to play.

Live features (Sentiment, Fight Mode, global statistics)

These features use the same database provider as the leaderboard, Supabase (Supabase, Inc., USA; our project is hosted in the EU, region Ireland). When you open Blitzkurs, your browser connects to Supabase to load the collective accuracy counter and to take part in the sentiment barometer. As with any connection, Supabase technically receives your IP address and browser information. Supabase acts as our data processor.

Sentiment barometer: When you make a Long/Short pick, only the direction (long or short) is broadcast to other visitors in real time. It is not linked to your name or any identifier and is not stored permanently.
Global statistics: After a round, an anonymous counter (rounds played, rounds correct) is incremented. No identifier or personal data is included.
Fight Mode: When you create or join a duel, your browser joins a temporary real-time room identified by a room code. Within the room, the display name you chose, a random session ID, and game events (ready status, entry timing and price, results, rematch requests, emoji reactions, connection pings) are exchanged with your opponent. This data exists only while the room is open and is not stored. If you win a duel, your display name and your number of wins are saved in the public Fight leaderboard, like in the solo leaderboard above. Choose a name you are comfortable showing publicly.

Newsletter (optional)

If you subscribe to our newsletter, the email address you enter is sent to our email service provider Kit (Kit, formerly ConvertKit, operated by ConvertKit, LLC, USA), which stores it and sends us the subscription and the newsletter emails on our behalf. Subscribing is entirely optional and never required to play. We use a double opt-in: you receive a confirmation email and are only added to the list after you confirm. Legal basis is your consent (Art. 6(1)(a) GDPR), which you can withdraw at any time via the unsubscribe link in every email or by contacting us at info@blitzkurs.com.

To display the sign-up form, your browser loads a script from Kit's servers (f.convertkit.com) when the page is opened, even if you do not subscribe. Kit therefore receives technical data such as your IP address and browser information. Data may be transferred to the USA; Kit acts as our data processor.

Analytics

We use Cloudflare Web Analytics, a cookie-free analytics tool, to see aggregate visitor counts. It does not use cookies or any client-side state, does not track you across sites, and does not collect personally identifiable information. No consent banner is required for this because no personal data or cookies are involved.

We also use Umami (provided by Umami Software, Inc., USA, via their hosted "Umami Cloud" service) for the same purpose — aggregate, anonymized visitor statistics such as page views and referrers. Umami does not use cookies, does not collect personally identifiable information, and does not track visitors across other websites; all data is anonymized at the point of collection. As with Cloudflare Web Analytics, no consent banner is required because no personal data or cookies are processed.

Hosting

Hosting provider: Cloudflare, Inc., 101 Townsend St, San Francisco, CA 94107, USA. Standard server access logs (IP address, timestamp, requested page, browser type) may be processed automatically by the hosting provider for security and operational purposes, under Art. 6(1)(f) GDPR (legitimate interest in running and securing the site). Cloudflare acts as our data processor for hosting-related access logs.

Your rights

Right to access (Art. 15 GDPR)
Right to rectification (Art. 16 GDPR)
Right to erasure (Art. 17 GDPR)
Right to restriction of processing (Art. 18 GDPR)
Right to data portability (Art. 20 GDPR)
Right to object (Art. 21 GDPR)
Right to lodge a complaint with a supervisory authority

Last updated: September 2026