Privacy Policy
Last updated: February 2026
Overview
BitLens is a client-side Bitcoin education and toolkit application. It is designed with privacy in mind: we do not track you, we do not use cookies, and we do not collect personal information.
Data we do not collect
- No analytics or tracking scripts (no Google Analytics, no Mixpanel, etc.)
- No cookies
- No user accounts or authentication
- No personal data, email addresses, or identifiers
- No advertising or ad-related tracking
Local storage
BitLens stores your preferences in your browser's localStorage to provide a better experience. This data never leaves your device. It includes:
- Theme preference — dark or light mode
- Calculator settings — currency, scenario, DCA amount, frequency, and time horizon
- Learning progress — which educational modules you have completed
- Cached market data — temporarily cached on-chain metrics to reduce API calls
- Quiz scores — your best scores per quiz category
- Onboarding preference — whether you have seen the welcome guide
- Language preference — your chosen language (English or Dutch)
- Fee and API cache — temporarily cached fee estimates and API responses to reduce network requests
You can clear this data at any time through your browser settings.
External services
BitLens fetches publicly available data from third-party APIs. These requests are made directly from your browser and are limited to read-only, public endpoints:
- Price data — CoinGecko, Coinbase, and CoinPaprika for live BTC prices
- Network data — Mempool.space and Blockstream for block height and difficulty
- Sentiment data — Alternative.me for the Fear & Greed Index
- Charts — TradingView widget for real-time market charts
- Macro data — FRED (Federal Reserve Economic Data) for M2 money supply, CPI, Fed Funds rate, and other economic indicators
- Node data — Bitnodes for the global Bitcoin node network map
- Additional price feeds — CoinCap as a fallback price source
These services have their own privacy policies. BitLens does not send any personal or user-specific data to these services.
Cloudflare proxy
Some API requests are routed through a Cloudflare Worker proxy to handle CORS restrictions. This proxy does not log, store, or modify your requests — it simply forwards them to the public API and returns the response. No personal data is transmitted or retained.
Your calculations stay private
All portfolio calculations, DCA projections, and scenario modelling happen entirely in your browser. Your Bitcoin holdings, investment amounts, and financial plans are never transmitted to any server.
Progressive Web App
BitLens can be installed as a Progressive Web App (PWA). The Service Worker caches application files on your device for offline access and faster loading. Cached data is limited to app assets and previously fetched API responses — no personal information is included in the cache.
Changes to this policy
If this policy is updated, the changes will be reflected on this page with an updated date. Because BitLens does not collect contact information, we cannot notify you directly — we recommend checking back periodically.
Contact
If you have questions about this privacy policy, reach out at hello@bitlens.app.