Bitcoin is a digital monetary network that operates without a central issuer. Launched in 2009, it was designed to allow value to be transferred between parties without relying on a bank, government, or any trusted intermediary.
Its defining structural property is scarcity. The protocol enforces a hard cap of 21 million bitcoin that can ever exist. New bitcoin are created as a reward to the computers that validate transactions — a process called mining — but that reward halves approximately every four years. This schedule means the rate of new supply decreases over time, and will eventually reach zero.
This makes Bitcoin fundamentally different from fiat currencies, which central banks can expand at discretion. Whether that scarcity is valuable depends on whether people find the network worth using. That is an empirical question the market continues to answer.
Bitcoin is also the oldest and most liquid cryptocurrency. Thousands of other digital assets exist, each with different mechanisms, trade-offs, and purposes. Bitcoin is best understood not as a proxy for the broader crypto market, but as its own distinct monetary experiment.