ECI-100 provides customers a suite of realtime cryptocurrency market index feeds. Each index selects top 100 cryptocurrencies based on their market capitalizations and generates index values with distinct quantitative measures in realtime. Indices are categorized into weighed, unweighted, and composite. They are distributed through realtime streaming data feeds in the form of timeseries, events, and interval data. ECI-100 is the first market index product in finance that delivers index values with those three types in realtime. ECI-100 indices are dynamically rebalanced in realtime so that they capture short-term (or, micro) market dynamics faster and more accurate as well as tracking long-term (or, macro) market movement. Other indices are typically rebalanced in a fixed amount of time such as monthly or quarterly. ECI-100 is the first market index product in finance that proactively selects index constituents and updates their weights in realtime. ECI-100 supports cache API for direct access to ECI-100 cache servers with low-latency and constant-jitter connectivity, and high-throughput I/O computation. Through dedicated or shared connections to the servers, customers can perform time-sensitive or high-throughput computational tasks. ECI-100 indices can be integrated into existing or new (high-frequency) realtime trading, market surveillance, and research products and services. ECI-100 is available on public clouds, private clouds, and customer on-premise data centers.