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Chapter 17

What Are Altcoins?

Every chapter so far has done arithmetic on exactly one asset. That's a deliberate choice, not an oversight — but it's worth naming plainly, because the choice is easy to mistake for a claim that nothing else in this space is worth understanding. It isn't that kind of claim. Thousands of other cryptocurrencies exist, under the loose label "altcoin," and they vary from each other so much that the label mostly just means "not Bitcoin" — it says almost nothing about what any given one actually is.

Chapter 17 of 24

Where the term comes from

"Altcoin" is short for "alternative coin" — any cryptocurrency that isn't Bitcoin. The term dates back to Bitcoin's early years, when a handful of forks and clones (Litecoin, Namecoin, Peercoin, among the first) started appearing as literal alternatives: same basic blockchain idea, different specific rules. The word stuck even as the space it describes stopped looking anything like "Bitcoin with one setting changed." Today it covers everything from a near-identical Bitcoin fork to a smart-contract platform with its own programming language to a token created as a joke — the only thing every altcoin genuinely has in common is that it isn't Bitcoin. That's a real category by exclusion, not a real category by similarity, which is the single most important thing to understand before looking at any specific one.

The supply question doesn't have one answer anymore

Chapter 1 and Chapter 5 covered Bitcoin's supply in detail: a hard 21 million cap, enforced by a geometric halving schedule every 210,000 blocks, checkable by anyone who wants to add up the arithmetic themselves. That specific design is not the industry default — it's one design choice among several genuinely different ones other projects have made:

Fixed, capped supply (Bitcoin's model, copied by some): a hard maximum written into the rules, same "count it yourself" property Fixed annual issuance, no hard cap: a set number of new coins per year, forever — supply grows on a schedule but never stops growing Uncapped, governance-adjustable supply: the rate of new issuance can be changed by a vote, a foundation, or a core development team — the number itself is a policy, not a constant Elastic / algorithmic supply: the coin count itself expands or contracts by protocol rule, targeting a price or peg rather than a fixed quantity

None of these is automatically better or worse in the abstract — a supply that can respond to conditions is a real, defensible design goal for some purposes. The point worth taking from this book specifically is narrower: Bitcoin's number is fixed and that fact is independently checkable, the way Chapter 7 described. For any given altcoin, whether its supply is fixed, growing, or adjustable is a fact you'd have to go look up individually — the label "altcoin" doesn't tell you.

The control question doesn't have one answer either

The same variance shows up one layer deeper, in who actually controls the rules. Bitcoin's ruleset changes only through a slow, contentious, opt-in process among a large number of independently run nodes and miners — no single company or founder can unilaterally change the 21 million cap, which is a meaningful part of why the number is trustworthy at all. That property doesn't transfer automatically to every other coin just because it also runs on a blockchain:

  • Genuinely decentralized: a handful of other projects have a similarly broad, independent validator or miner base with no single controlling party — real, but rarer than marketing copy usually suggests.
  • Foundation- or team-controlled: many altcoins were created, are actively developed, and can have their core rules changed by one company, foundation, or small founding group — a meaningfully different trust model from Bitcoin's, even when the coin is otherwise well-built and honestly represented.
  • Pre-mined: a substantial share of many altcoins' total supply was created and allocated to founders, early investors, or a foundation treasury before the coin was ever available to the public — again, not automatically a red flag by itself, but a fact that changes who benefits from the coin's success and by how much, and one that's worth knowing before assuming "decentralized" applies evenly to every project using the word.
Two independent axes — supply and control vary separately vertical axis: control — decentralized (top) to team/foundation (bottom) Bitcoin the only point pinned to a corner fixed supply,centrally governed decentralized,but supply can still grow adjustable supply,central control — common fixed, capped supply uncapped / adjustable supply

Two independent axes, not one spectrum: how fixed a coin's supply is, and how centralized its control is, vary separately. Bitcoin sits pinned to one corner — fixed supply, broad decentralized control. Altcoins scatter across every other combination, which is why "altcoin" describes almost nothing about any specific project.

What altcoins are actually for varies just as much

Bitcoin's stated purpose has stayed narrow and consistent since its whitepaper: a peer-to-peer electronic cash system with a fixed, auditable supply. Altcoins collectively cover far more ground, and lumping them together obscures how different the goals are:

Smart-contract platforms: general-purpose programmable blockchains — code that runs when conditions are met, used to build other applications on top Privacy coins: designed specifically to obscure transaction details that Bitcoin's own public ledger leaves visible — Chapter 20 covers exactly what that ledger does and doesn't reveal for Bitcoin itself Stablecoins: designed to hold a steady price, usually pegged to a fiat currency, by backing (asset reserves) or by algorithm — the opposite design goal of a scarce, appreciating asset Memecoins: created around a joke, a community, or pure speculation, with no stated technical or economic purpose beyond that ...and many purpose-built variants beyond these four broad groups.

A stablecoin and a memecoin have almost nothing in common except the word "crypto" and the word "altcoin" — treating either one as representative of "what altcoins are" misses the range entirely.

Why this book still only does the arithmetic for one

None of the above is an argument that altcoins are categorically worthless or that everyone building outside Bitcoin is acting in bad faith — plenty of real, honestly-run projects exist in that huge variance, alongside plenty of dishonest ones, the same way any large, fast-growing field contains both. The reason this book stays Bitcoin-only isn't a verdict on that whole space; it's a scope decision, stated plainly rather than left implicit: everything in this book is built on facts that are fixed and independently checkable by rule, not facts that require trusting a specific team's word or reading a specific project's fine print. Chapter 1's cap, Chapter 5's schedule, Chapter 7's audit — all of it holds regardless of who's running this website, because none of it depends on anyone's promise. That's a genuinely rare property, and it's the one this book was written to explain in full. Extending the same rigor to even a handful of the thousands of other coins that exist, each with its own supply model, control structure, and purpose, would be a different, much longer book — and a dishonest one if it tried to reuse Bitcoin's specific guarantees as a stand-in for coins that don't actually share them.

"Altcoin" describes everything Bitcoin isn't. It doesn't describe what any specific one actually is — that's a question you still have to ask, one coin at a time.