Every Stablecoin Has an Off-Switch. frUSD Doesn't.

Every dollar that lives on a blockchain today has someone standing behind it who can turn it off.

That isn't a flaw in the stablecoin market. It's the design. The largest dollar tokens ship with a function most holders never read: the one that lets the issuer freeze an address on demand. It is used rarely, and it is real every second it exists. The dollar you hold is only as free as the company that mints it decides to let it be.

frUSD is built on the opposite assumption. It is a dollar with no one to call.

First, the ground had to shift

You don't launch a censorship-resistant dollar on hope. You launch it on infrastructure that has earned the right to hold value.

Two things happened to make frUSD possible.

The first: metashrew and alkanes-rs are entering their first formal audits, on the back of a significant round of security upgrades. The metaprotocol that indexes and executes Bitcoin-native contracts is being examined the way any system meant to custody real money should be, line by line, by people whose job is to break it.

The second: subzero-rs has reached maturity. Sharding and extended deployments now run across signing groups in a component model, composing toward a larger federated custodian. That last phrase is the whole point. Custody is no longer one wallet, or one group, or one point of failure. It is a fabric of signers, each holding a restricted slice of authority, that can be assembled into whatever shape a market needs.

That fabric is what lets us stage frUSD.

The flaw was always the issuer

Read the risk in a stablecoin from the outside in. The first thing that can go wrong isn't the collateral, or the chain, or the smart contract. It's the issuer: the single company at the top of the stack that can, by policy or by order, freeze what you hold before any of the rest of the system ever gets a vote.

frUSD steps out from under that.

frUSD is backed by vault tokens on the EVM side. The peg does not sit downstream of a stablecoin issuer's mint, so it does not inherit that issuer's first-line censorship risk. The dollar exposure is real; the off-switch is not there to be pulled. You get the unit of account without handing anyone the key to your balance.

Backing it with the dollar that already won. Let's be blunt about the part that usually gets lost in theory: on-chain, the canonical dollar is already decided. It's USDC and USDT. They're what the market quotes against and treats as cash. frUSD doesn't try to unseat that; it anchors to it. The EVM-side vault tokens behind frUSD hold exactly that exposure, so the peg tracks the dollar the whole ecosystem has already agreed on, not a synthetic approximation of it. Backing with the canonical dollar is simply the most direct fit for an L0 stable on Bitcoin: you meet the market where it is instead of asking it to adopt a new unit from scratch. What SUBFROST removes isn't the dollar; it's the off-switch on holding and moving it, and that comes from frUSD's own layer: the vault structure, the restricted signer market, and settlement on Bitcoin. The issuer can still do whatever issuers do upstream; at the layer you actually touch, there's no single hand on the valve.

A dollar that composes

A stablecoin you can only hold is a museum piece. frUSD is built to be executed.

frUSD composes directly into transaction scripts, carried out by signing groups operating under restricted permissions. Those groups act as keepers: they hold no discretion over your funds, only the authority to run the exact script you authorized. And because they front the mechanics, they can offer the thing EVM users take for granted and Bitcoin never had: gas-as-a-service. You describe the outcome. The keepers pay for and assemble the moves that get you there.

At the top of the range, federated custody of frUSD runs across a large set of signers, the full fabric, for the balances that demand it.

But SUBFROST doesn't only run at that scale. The same machinery, in a smaller orchestration, exists to beat a problem Bitcoin's base layer has never solved on its own: user experience.

Custody at protocol scale, UX at human scale

The hard part of Bitcoin was never the money. It was the last mile.

Two examples of what the fabric makes ordinary.

Coming in. Bridge BTC to USDT, and in the same motion swap a small slice of that output into ETH, just enough to seed a fresh identity on the ERC-20 side. One intent, and you land on the other chain already funded and ready to transact. No cold-start. No separate errand to go acquire gas.

Going out. Bridge USDC into the frUSD peg on the EVM side, and that action can schedule an arbitrary PSBT to broadcast on Bitcoin. The output of the trade is swapped on the frBTC/frUSD pool inside a transaction script that burns frBTC and pays out BTC to a brand-new identity on the Bitcoin side.

Follow either path to its end and you'll notice what it really is. The complete route from BTC to USDT or USDC, in either direction, is a combination of many signing groups, each doing its restricted job, none of them the single point that could stop the trade. That is not a bridge with a company behind it. That is a truly decentralized market for spot.

Why this has to live on Bitcoin

There is a reason we insist on settling here, and it comes down to scarcity.

A Bitcoin block gives you four megabytes. That's the ceiling. Everything the protocol will ever do is bounded by that space, and that constraint is not a weakness. It's the filter. It forces a question every serious system should answer: of all the work in the world, what deserves to live forever on proof-of-work?

Our answer has always been the same. The highest tier of value. And there are few markets that clear that bar the way BTC/USD does. It is the pair the entire industry is priced against. If any market earns permanent settlement on the most secure ledger ever built, it's that one.

So we put it there. frUSD leans on the L0 layer and on Bitcoin itself as the data backend, through the metaprotocol. Bitcoin is not a bystander to the trade, it is the record of it.

And frUSD is a step, not a destination. It moves us closer to dxBTC and to a unified yield model native to Bitcoin L1: yield that doesn't ask you to leave the chain, wrap into someone else's system, or trust an issuer's promise to stay solvent.

The longer game

This is the saga toward free finance, and frUSD is the part of it where the dollar comes home.

A stablecoin whose peg no one can freeze at the source. A spot market assembled from many signers instead of one custodian. A settlement layer chosen because it's the hardest one to corrupt, not the cheapest one to spam.

The stablecoin market gave you a dollar with an off-switch and asked you to trust that no one would ever flip it. We're building the version that never had the switch to begin with.

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frUSD is in staging. Mechanics described here reflect the SUBFROST design as of launch preparation; specifics may evolve as the framework ships. Nothing here is financial advice.