Bitcoin (BTC)

Bitcoin is the asset that started the category: a peer-to-peer digital cash system proposed in a 2008 whitepaper by the pseudonymous Satoshi Nakamoto and launched on 3 January 2009. Its core innovation was proving that a decentralised network of strangers could agree on a shared ledger without a central authority, using proof-of-work mining and a hard-coded 21 million supply cap. Every other coin on this site is, in some sense, a response to what Bitcoin proved was possible.

How Bitcoin actually works

Bitcoin's ledger is secured by proof-of-work: miners compete to solve a computationally expensive puzzle, and the winner adds the next block of transactions in exchange for a block reward plus transaction fees. This makes rewriting history prohibitively expensive — an attacker would need to out-spend the entire honest network's hardware and electricity, an approach known as a 51% attack, which becomes harder as more mining power (hashrate) joins the network.

The protocol is deliberately conservative and slow to change. Bitcoin's scripting language supports only simple, non-Turing-complete conditions, which limits what can be built directly on the base layer but also limits the attack surface. Most experimentation — from the Lightning Network's instant payment channels to newer inscription-based token standards — happens on layers built on top of, rather than inside, the base protocol.

The halving and fixed supply

New BTC enters circulation only as a mining block reward, and that reward is cut in half roughly every four years (every 210,000 blocks) in an event called the halving — from 50 BTC per block in 2009 down through successive halvings toward the 21 million cap, expected to be fully mined around the year 2140. This hard-coded scarcity, rather than any central bank decision, is the basis of Bitcoin's 'digital gold' framing.

Because the cap and issuance schedule are enforced by the protocol every node runs, changing them would require overwhelming consensus across miners, node operators and users — in practice this makes Bitcoin's monetary policy far harder to alter than any single company's or government's.

What it's used for

In practice Bitcoin is held predominantly as a long-term store-of-value asset and as the base pair on almost every exchange, rather than used for everyday retail payments — transaction costs and confirmation times make small, frequent purchases impractical on the base layer, though the Lightning Network addresses this for some use cases. Institutional adoption has grown through spot Bitcoin ETFs in several jurisdictions and corporate treasury allocations.

Tokenomics

Last verified: 8 July 2026. before you rely on any figure — live circulating supply and market cap are never published here; check a live tracker.

Risks & criticisms

• Price volatility remains substantial even after 15+ years of history; large drawdowns (50%+ from highs) have occurred multiple times.
• Regulatory treatment varies significantly by jurisdiction and can change with little notice — always check your own market's current rules.
• Self-custody responsibility is real: losing private keys or seed phrases means permanently losing access, with no recovery mechanism.

Frequently asked questions