Stablecoin Swap.

A Stablecoin Swap is an exchange of one dollar-pegged token for another, carried out through a pool or venue built around assets that are each designed to trade near one US dollar. Unlike swapping ETH for a stablecoin, where the exchange rate moves with the market, this kind of trade mostly moves around a fixed point — one unit should buy roughly one unit of the other asset. That narrow expected range is what lets specialised pools price the trade with unusually tight spreads, and it is the main reason traders route dollar-to-dollar conversions through dedicated infrastructure rather than a general-purpose exchange pool.

People reach for this kind of trade for reasons that have nothing to do with speculating on price, since both sides are meant to hold the same value.

Moving between venues and chains

Not every exchange, lending market or liquidity pool accepts every stablecoin. A trader holding USDT who wants to supply liquidity on a venue that only lists USDC will convert first, trading at close to parity rather than cashing out to fiat and back.

Rotating for yield or risk

Yield rates on USDC, USDT and DAI drift apart across lending markets, and some users prefer the reserve composition behind one issuer over another. Converting lets them move their balance to whichever token currently offers the better rate or the backing they trust, without ever leaving the dollar-denominated side of the market.

Fees on this kind of exchange are usually the lowest in DeFi because the pools are built for assets expected to stay close to parity, which lets them use tighter curves than a pool holding two volatile tokens. Slippage only grows when an order is large relative to the pool's depth, or when one side of the pair is actually losing its peg. The table below compares the usual trade-offs across venue types.

Venue type	Typical fee	Typical slippage
Stable-optimised AMM (e.g. Curve)	0.01%–0.04%	Under 0.05% on moderate size
General-purpose DEX pool	0.05%–0.30%	Higher, widens with order size
Centralized exchange	Maker/taker fee, varies	Low on liquid pairs, spread-dependent

Why stable-specific pools quote tighter

A pool designed for pegged assets, like the ones described in the Curve docs, uses a pricing curve that stays flat near the expected one-to-one rate and only steepens once a trade pushes the balance far from parity. That shape is what lets a routine conversion clear with minimal price impact compared to a curve built for two assets with no expected relationship.

Every such trade assumes both tokens are close to one dollar, so the risk that actually matters is the one that breaks that assumption rather than ordinary market volatility.

What keeps the peg in place

Fiat-backed tokens such as USDC and USDT are meant to be redeemable against reserves held by their issuer, a structure Wikipedia's overview of stablecoins explains in more depth, while crypto-collateralized designs like DAI rely on over-collateralized vaults instead of a bank account. The mechanism differs by token, and the strength of that mechanism is what a holder is really trusting when they keep a balance in any one of them.

What a depeg looks like

A depeg is a period where a token trades noticeably away from one dollar, usually on doubts about reserves, redemption, or collateral. Converting during a depeg can mean trading into the weaker side at a discount or paying a premium for the stronger one, so it is worth checking a live price before moving any meaningful size, not just assuming the quoted rate reflects a genuine dollar.

The mechanics are the same across most venues, which is what makes this trade quick once you have done it a few times.

• Connect a self-custody wallet and open a stable-optimised pool or exchange route.
• Select the token you hold and the one you want, for example USDC to USDT.
• Enter the amount and review the quoted rate, fee and expected slippage.
• Approve the token if needed, then sign the swap transaction.
• Confirm the received amount lands in your wallet at close to the quoted rate.

A trade run through a decentralized pool never requires giving up custody; the contract only moves the exact tokens you approve, in a transaction you can read before signing.

Keep approvals tight

Grant a limited allowance rather than an unlimited one, so a pool contract can only ever spend the amount you intend for that trade. Revoking old approvals you no longer need, which you can verify on a block explorer such as Etherscan, keeps the surface of any future exploit smaller.

The rule that never changes

No pool, wallet or support channel ever needs your seed phrase to complete the exchange. A legitimate transaction only asks for a signature in your own wallet interface — anyone requesting your recovery words by any other route is attempting fraud.

The three most common legs of this trade differ mainly in who stands behind them and how transparent that backing is. USDC is issued by Circle, with reserve reporting described on the Circle USDC page, and is widely used across regulated venues. USDT, issued by Tether and detailed on Tether's own site, carries the deepest liquidity of any stablecoin and is listed almost everywhere a dollar-to-dollar swap is offered. DAI takes a different path entirely, backed by over-collateralized crypto vaults rather than a bank-held reserve, which trades issuer risk for smart-contract and collateral risk.

Picking a side for the swap

There is no universally correct choice; the right token depends on where you plan to use the balance afterward, which venues list it, and how much you weigh issuer transparency against liquidity depth. Many traders simply hold whichever pair a given platform requires and convert each time that requirement changes.