A stablecoin is a privately issued digital token designed to hold a fixed exchange rate with an existing currency, almost always the US dollar, by backing each token with reserves held by the issuer. A central bank digital currency, or CBDC, is a digital form of a nation's currency issued directly by its central bank, making it a liability of the state rather than of a commercial issuer.

The two are frequently discussed as rivals, and in one sense they are: both compete to become the digital form in which people hold and move national currencies. Tether's USDT and Circle's USDC are the largest stablecoins; China's e-CNY, the Bahamian Sand Dollar, and Nigeria's eNaira are among the CBDCs already in circulation, and in the Bank for International Settlements' 2023 survey, 94 percent of the 86 responding central banks reported being engaged in some form of CBDC work.

But the framing of rivals conceals what the two instruments have in common, which is more fundamental than what separates them. Both are digital representations of an existing national currency. Both inherit that currency's supply policy, its inflation behavior, and its distribution history. The choice between them is a choice of issuer and of oversight model, not a choice of monetary properties.

This page explains how each works, then examines the dimension most comparisons omit: what neither instrument changes, and what a structurally different design looks like on the same criteria.

A fiat-backed stablecoin maintains its peg through a simple issuance loop: a customer sends the issuer one dollar, the issuer mints one token, and the dollar joins a reserve portfolio of cash and short-term government debt. Redemption runs the loop in reverse.

The design has real strengths. Tokens settle on public blockchains around the clock, cross borders as easily as any other on-chain transfer, and hold their dollar value far better than speculative crypto assets. For participants in economies with weak local currencies, a dollar stablecoin can be the most accessible dollar instrument available.

Three structural properties come with the design:

2.1 Issuer Dependence

Every token is a claim on a private company's reserve portfolio. The holder depends on the issuer's solvency, the quality and auditability of the reserves, and the issuer's continued willingness and legal ability to honor redemptions. Major issuers can also freeze tokens at specific addresses to comply with legal orders; the instrument is administered, not bearer.

2.2 Inflation Inheritance

A token pegged to the dollar tracks the dollar by definition, in both directions. The US dollar has lost approximately 87 percent of its purchasing power since 1971, per the US Bureau of Labor Statistics CPI calculator. A perfectly managed stablecoin transmits that erosion to its holders with perfect fidelity: the peg is the product, and the peg includes the inflation.

2.3 Distribution by Purchase

Stablecoins are acquired by paying for them with existing money. There is no distribution mechanism at all in the monetary sense; access to the instrument maps one-for-one onto wealth already held. How different entry paths shape who benefits from a monetary system is covered in How Money Is Created and Distributed.

A CBDC replaces the private issuer with the central bank itself. Where a stablecoin holder holds a claim on Circle or Tether, a CBDC holder holds a direct liability of the state, the digital equivalent of holding a banknote rather than a bank deposit.

This removes the issuer-solvency risk that stablecoins carry: a central bank cannot fail to honor a liability denominated in the currency it issues. It also changes the oversight model. A retail CBDC gives the central bank, or intermediaries operating under its rules, a transaction record at the level of the individual holder. Published CBDC designs vary in how much anonymity they permit for small payments, but the design center of gravity across current projects is visibility: the ability of the issuing authority to observe, and in most designs to condition or restrict, the movement of the currency. This is a stated design goal in several projects, motivated by anti-money-laundering and monetary policy considerations, and it is the property most public debate about CBDCs centers on.

Two boundaries follow from the design:

3.1 National Scope

A CBDC is the national currency in digital form, and its reach is the reach of that currency. A digital naira is not spendable in Manila, and a digital yuan does not settle an invoice in Nairobi without crossing the same foreign-exchange infrastructure that fiat crosses today. Cross-border CBDC interoperability is the subject of ongoing central-bank pilot projects, not a property of any deployed system.

3.2 Monetary Continuity

A CBDC changes the form of the currency, not its policy. The supply remains managed by the central bank's mandate, the currency's inflation trajectory is unchanged, and new money continues to enter the economy through the same channels as before. The digital dollar would be the dollar; the digital euro would be the euro. That continuity is intentional: central banks describe CBDC as a complement to cash, not a monetary reform.

Most stablecoin-versus-CBDC comparisons weigh issuer trust against state trust, private innovation against public control. The dimension they omit is the monetary one: both instruments digitize an existing unit, and digitizing a unit changes none of its monetary properties.

Three properties pass through both instruments untouched:

Supply policy. The supply of a dollar stablecoin is the demand for wrapped dollars; the supply of a digital dollar is the Federal Reserve's policy. In neither case does the instrument constrain issuance of the underlying unit. A holder seeking a fixed-supply money finds it in neither.

Interest architecture. Both instruments live inside the credit system of their underlying currency. The reserves behind a stablecoin earn interest for the issuer; a CBDC coexists with, and in some designs pays or charges, the central bank's policy rate. Neither removes interest from the structure of the money.

Distribution. Neither instrument distributes anything. Stablecoins are purchased; CBDCs are exchanged one-for-one for existing balances. Whoever held the currency before holds its digital form after, in the same proportion.

Placing the two digitizing instruments alongside Bitcoin and GX makes the structural differences visible. Bitcoin, whose 2008 white paper introduced issuance without an issuer, changes the supply policy but distributes by mining; GX changes the supply policy, the interest architecture, and the distribution mechanism together.

Each column is internally consistent. Stablecoins optimize for dollar access on open rails. CBDCs optimize for sovereign control of the digital currency layer. Bitcoin optimizes for issuance without trust. The GX column reflects a fourth objective: a circulating medium of exchange whose properties are fixed by specification rather than by issuer discretion.

GX is not a digitized national currency and not a speculative asset. It is a separate monetary unit whose properties are defined at the protocol level, which is what places it in a different category from every instrument above.

Fixed supply. The protocol specifies GX 1.25 trillion units, permanently. No mint function exists in the code, so no issuer, steward, or majority can expand the supply. Where a stablecoin inherits its underlying currency's supply policy and a CBDC is that supply policy, the GX supply is a constant.

Grant distribution. Units reach participants through allocation grants tied to verified enrolment, not through purchase or mining. The supply enters circulation across the participant base from the start, which is the structural basis of the protocol's non-speculative design: there is no early-buyer class holding supply as a position to be unwound.

The velocity mechanism. A fixed supply invites hoarding, and the protocol addresses this structurally rather than by exhortation: a velocity mechanism of 3 to 6 percent annually applies to idle balances, keeping the fixed supply circulating as a medium of exchange. The mechanism, its thresholds, and its historical lineage are explained in What Is Demurrage Currency.

Zero-interest lending. The protocol's loan pool provides capital at zero interest, with the lending rules encoded in the protocol rather than set by institutional discretion. Neither stablecoins nor CBDCs alter the interest architecture of their underlying system; GX defines a different one.

One unit, everywhere. GX is a single global unit: the unit held in Nairobi is the unit spent in Manila, with no exchange rate between them. Person-to-person transfers cost at most 0.025 percent. For comparison, the World Bank's Remittance Prices Worldwide data shows traditional remittance channels extracting 3 to 7 percent per transfer. A stablecoin approximates this reach on the rail layer but reintroduces the national unit, and its conversion costs, at each endpoint; a CBDC does not attempt it.

These properties are claims about a specification, and the specification is public. The complete parameter set, including the velocity mechanism bounds and the treasury allocation rules, is documented in the protocol specification and examined against four foundational objections in The Four Foundational Questions of Monetary Systems.