Around 534, on the site's counting rule — assets with their own base-layer blockchain and their own consensus mechanism. Alternative aggregators quote figures in the thousands because they count every wrapped coin, staked derivative and stablecoin alongside the base asset each one represents. See the manifesto for the rule, and the long explanation for what falls out of it.

Yes — prices refresh every 60 seconds from a rotating list of major exchanges. Live-feed coverage grows over time as new venues are added; the exact source is stamped on each asset page. When no exchange carries an asset, a six-hourly snapshot from CoinGecko / CoinMarketCap / CoinPaprika fills in.

A ledger of transactions, chained cryptographically so that each block references the hash of the block before it. Once a block is added, changing anything inside it changes its hash, which breaks every block after — so history is append-only, and the "chain" gives the ledger its name. The important detail: the chain is only meaningful because a network of nodes agrees on which chain is the real one. That agreement is called consensus.

Consensus is the rule the network uses to decide which of many possible histories is the real one. Proof of Work asks miners to solve a puzzle whose difficulty scales with the network — the miner who solves it first proposes the next block, and the puzzle is expensive enough that faking a longer history costs more than the reward. Proof of Stake replaces the puzzle with a deposit: validators stake their own coins as a bond, and are slashed if they sign a competing history. Bitcoin uses PoW; Ethereum since 2022 uses PoS. Both work; each trades security against different threats.

A chain that runs on top of a base-layer cryptocurrency and inherits its security. Bitcoin's Lightning Network and Ethereum's rollups (Arbitrum, Optimism, Base) are the canonical examples. Transactions execute cheaply and quickly on the L2, but the state resolves back onto the base chain, and it is the base chain's consensus that ultimately settles them. If the L2 operators disappear, funds can still be recovered on the base chain. The security guarantee comes from the parent.

A sidechain is a separate chain that connects to a base-layer network by a two-way peg — coins can be moved across, but each chain runs its own validators and its own consensus. Polygon PoS, Rootstock and Liquid are the reference cases. A sidechain has its own security budget, provided by its own validator set. If that set is compromised, the sidechain's coins are at risk and the base chain cannot help.

That is the distinction the site is here to draw. An L2 inherits security from Bitcoin or Ethereum; a sidechain runs its own security next to them. Merging the two under one tab with an internal picker would hide the difference — and the difference is the whole point. The site's founding question is who guards the security; the two answers are different, so they get separate places.

A hard fork is a protocol upgrade that new nodes accept and old nodes reject — the rules changed. A chain split is what happens when a hard fork does not get the coordination it needed: two groups of nodes keep running two different versions, and two chains exist from that block forward. Same mechanism at activation, different outcome in the days after. A short journal post covers the distinction.

Two ways a chain records who owns what. UTXO (unspent-transaction-output) tracks coins as discrete "notes": each transaction consumes notes and creates new ones, and your balance is the sum of the notes you can spend. Bitcoin, Bitcoin Cash and Litecoin use it. The account model tracks a running balance per address, like a bank ledger — deposits add, withdrawals subtract. Ethereum and most newer chains use it. UTXO is simpler to reason about and easier to make private; the account model is simpler for smart contracts. Each asset's page names which one its chain uses.

The site's data pipeline can no longer find it, so it stops appearing in the ranking. Dozens of fork-era chains from 2017–2019 fell out this way. If a chain resumes producing blocks, it comes back on the next data-refresh cycle.