CoinPeek

Real-time BTC and ETH prices on the badge, network fees for both chains, and a converter.

CoinPeek - Your lightweight crypto companion for Chrome Track Bitcoin and Ethereum prices in real-time without leaving your browser. CoinPeek is designed for traders, developers, and crypto enthusiasts who need quick access to market data. KEY FEATURES: Live Price Tracking - Real-time Bitcoin and Ethereum prices - 24-hour price change with visual indicators (green/red) - Price displayed in extension badge for instant visibility Network Fee Monitoring - Ethereum gas fees (low, standard, fast) - Bitcoin transaction fees in sat/vB - Multiple API sources for reliability Quick Converter - Convert between BTC, ETH, and USD instantly - Swap currencies with one click - Precise decimal calculations PERFORMANCE: - Updates every 60 seconds automatically - Smart caching reduces API calls by 70% - Lightweight design - minimal memory footprint - Instant popup loading with cached data PRIVACY-FIRST APPROACH: - All data stored locally on your device - No account required - No personal data collected - No tracking or analytics - Open source on GitHub PERMISSIONS EXPLAINED: We only request what's absolutely necessary: - Storage: Save cached prices locally for faster loading - Alarms: Schedule background price updates We do NOT access your browsing history, tabs, cookies, or any personal data. DATA SOURCES: - CoinGecko: Cryptocurrency prices (public API) - Blocknative: Ethereum gas fees - Mempool.space: Bitcoin fees (with fallbacks) PERFECT FOR: - Crypto traders monitoring market movements - Developers checking gas fees before deploying - DeFi users optimizing transaction timing - Anyone interested in cryptocurrency prices TECH SPECS: - Built with Manifest V3 (latest Chrome extension standard) - Vanilla JavaScript - no heavy frameworks - Service Worker architecture for efficiency - Responsive modern UI with dark theme Open source and free forever. Check out our GitHub for the full source code. «What's new» Ethereum network fees are back. The gas service this used shut down in June 2026, so the fee row could not load and Bitcoin no longer shows a 0 sat/vB reading that a transaction cannot use. What's new 1.1.4 Bitcoin fee estimates no longer overstate a quiet mempool. Fees below 1 sat/vB were thrown away, so the extension fell back to a built-in number and could suggest paying ten times more than needed. It now shows the real fees below 1 sat/vB that the network accepts.