Altcoin
Any cryptocurrency other than Bitcoin. The term covers everything from established networks like Ethereum and Solana to thousands of smaller experimental tokens, ranging widely in technology, market cap, and credibility.
Where the term came from
When Bitcoin was the only meaningful cryptocurrency, the term "altcoin" — short for "alternative coin" — described any of the early Bitcoin clones launched between 2011 and 2013: Litecoin, Namecoin, Peercoin. Each tweaked some parameter (block time, hashing algorithm, total supply) to differentiate from Bitcoin.
Today the term is much broader. Anything that isn't Bitcoin is technically an altcoin — including Ethereum, the second-largest crypto by market cap, with a fundamentally different design (programmable smart contracts vs. Bitcoin's simpler scripting).
Categories
Among the thousands of altcoins, a few rough categories cover most of the meaningful ones:
- Layer 1 platforms — independent blockchains running their own consensus: Ethereum, Solana, Cardano, Avalanche, Sui, Aptos, Monad.
- Layer 2 tokens — networks that scale Ethereum: Arbitrum, Optimism, Polygon, Base (which uniquely has no token).
- DeFi tokens — governance and revenue claims on protocols: Aave, Uniswap, Lido.
- Stablecoins — algorithmically or collaterally pegged to fiat. Technically altcoins, but priced to a peg.
- Memecoins — value driven primarily by community and meme energy: Dogecoin, Shiba Inu, Pepe, plus thousands of micro-caps.
- Privacy coins — designed to hide transaction details: Monero, Zcash.
Why the distinction still matters
Bitcoin dominance — Bitcoin's share of total crypto market cap — is one of the most-watched crypto market indicators. Capital tends to rotate: into Bitcoin first when uncertainty rises, then out into altcoins when risk appetite returns. The "altcoin / Bitcoin" ratio frames most short-term crypto trading discussion. Periods of altcoin outperformance are called altseasons.
Fundamentals vs. speculation
Altcoins span a wide quality spectrum. Ethereum, Solana, and a small handful of others have meaningful network usage, real revenue, and persistent developer activity. The vast majority of the long tail trades on attention with little under it. The 2024–25 cycle was particularly extreme: at one point Solana memecoins generated more daily DEX volume than the rest of crypto combined, with most tokens going to zero within weeks of launch.