CoinScreener

Aggregates real-time and historical cryptocurrency market data from multiple exchanges (likely Binance, Coinbase, Kraken, etc.) through their public APIs, normalizing disparate data schemas into a unified format for consistent querying. The system likely implements exchange-specific adapters that handle rate limiting, data freshness guarantees, and format translation, enabling users to query across exchanges without managing individual API connections.

Provides a rule-based filtering engine that allows users to define screening criteria across multiple dimensions (market cap ranges, 24h volume thresholds, price change percentages, liquidity metrics, listing age) and apply these filters to the aggregated cryptocurrency universe. The system likely uses a query builder UI that translates user-defined conditions into database queries or in-memory filtering operations, enabling rapid iteration of screening strategies without requiring SQL knowledge.

Displays live cryptocurrency prices, 24-hour price changes, market cap rankings, and trading volume in a responsive web interface with periodic data refresh (likely via WebSocket connections or polling intervals of 5-30 seconds). The visualization layer likely uses lightweight charting libraries (e.g., Chart.js, Lightweight Charts) to render price sparklines and trend indicators without the overhead of full technical analysis platforms, prioritizing speed and simplicity over feature depth.

Allows users to create and maintain personal watchlists of cryptocurrencies with persistent storage (likely using browser localStorage for free tier, server-side database for premium accounts). The system tracks user-selected coins and enables quick access to custom subsets of the full cryptocurrency universe, with features like adding/removing coins, organizing into multiple lists, and potentially setting custom alerts or notes per coin.

Implements a subscription model that gates advanced features (likely detailed analytics, alert systems, API access, or premium data sources) behind a paywall while providing core screening and data aggregation functionality for free users. The system likely uses role-based access control (RBAC) or feature flags to conditionally render UI elements and restrict API endpoints based on subscription tier, with a clear upgrade path to premium features.

Provides search functionality to locate cryptocurrencies by symbol, name, or category (e.g., 'DeFi tokens', 'Layer 2 solutions', 'Stablecoins') within the aggregated cryptocurrency universe. The search likely uses full-text indexing or fuzzy matching to handle typos and partial matches, returning ranked results with basic metadata (price, market cap, change %) to help users quickly identify coins of interest before applying detailed screening filters.