Time vs Slippage

Every exchange mechanism makes a tradeoff. DollarStore's tradeoff is explicit: perfect price, variable time.

The traditional tradeoff

AMMs and order books guarantee execution but not price:

Mechanism	You get	You give up
AMM (Uniswap)	Instant execution	Price (slippage + fees)
Order book	Price discovery	Instant execution (may not fill)
DollarStore	Exact 1:1 price	Instant execution (may queue)

When you get instant execution

Swaps execute instantly when reserves are sufficient:

USDC reserves: 50,000
Your swap: 10,000 USDC → USDT
Result: Instant, 10,000 USDT received

When you wait

If reserves are insufficient, you have a choice:

USDC reserves: 5,000
Your swap: 10,000 USDC → USDT

Option 1: Partial fill + queue
  → Receive 5,000 USDT instantly
  → Queue for remaining 5,000

Option 2: Partial fill + DLRS
  → Receive 5,000 USDT instantly
  → Receive 5,000 DLRS (redeem later)

Option 3: Revert (aggregator mode)
  → Transaction fails
  → Route through different venue

Predictable behavior for integrators

The swapExactInput function (for aggregators) never queues—it either executes fully or reverts. This makes integration predictable:

// This either gives you exactly amountIn of USDT, or reverts
// Never partial fills, never queues
uint256 out = dollarStore.swapExactInput(
    USDC, USDT, amountIn, amountIn, recipient, deadline
);

Aggregators check getSwapQuote first. If it returns the full amount, the swap will succeed. If it returns 0, route elsewhere.

Why this works

Stablecoin demand is cyclical. USDC holders sometimes want USDT; USDT holders sometimes want USDC. Over time, flows roughly balance.

DollarStore doesn't try to incentivize balance through fees or rates. It just processes swaps fairly: first come, first served, always 1:1.