Price Engine

A 3-tier pricing strategy that attempts progressively broader methods to determine token USD values on Sepolia.

Source: server/routes/api.ts (price fetching functions)

Pricing Tiers

Tier 1: Uniswap V3 Direct Quote

Calls the Uniswap V3 QuoterV2 contract on Sepolia to get a direct token → USDC quote. Tries three fee tiers in order:

Fee Tier	Percentage	Best For
500	0.05%	Stablecoins
3000	0.3%	Most pairs
10000	1%	Exotic/volatile

The first successful quote is used. The fee tier is stored and passed through to swap execution.

Tier 2: Multi-Hop via WETH

If no direct USDC pair exists, routes through WETH:

token → WETH → USDC

This catches tokens that only have WETH pairs on Uniswap V3.

Tier 3: Eloqura DEX Pools

Falls back to Eloqura V2 AMM pools:

1. Token/USDC pair: Check reserves and calculate price directly

2. Token/WETH pair: Calculate token price in ETH, then convert via ETH/USD price

// Get pair address from Eloqura Factory
const pairAddress = await factory.getPair(tokenAddress, usdcAddress);

// Read reserves
const [reserve0, reserve1] = await pair.getReserves();

// Calculate price based on token ordering
const price = isToken0 ? reserve1 / reserve0 : reserve0 / reserve1;

Caching

Token prices are cached in an in-memory Map with a 5-minute TTL:

const apiCache = new Map<string, { data: unknown; expiresAt: number }>();
const CACHE_TTL = 5 * 60 * 1000; // 5 minutes

This reduces Alchemy compute unit usage significantly, especially for the Uniswap V3 QuoterV2 calls which consume CUs on every invocation.

Fee Tier Mismatch Bug: Quote logic tries multiple fee tiers and finds the best one. Swap execution must use the same fee tier: not a hardcoded default. Store the fee tier in the quote object and pass it through.

Key Addresses

Contract	Address (Sepolia)
Uniswap V3 Quoter	0xEd1f6473345F45b75F8179591dd5bA1888cf2FB3
Uniswap V3 Router	0x3bFA4769FB09eefC5a80d6E87c3B9C650f7Ae48E
USDC	0x1c7D4B196Cb0C7B01d743Fbc6116a902379C7238
Eloqura Factory	0x1a4C7849Dd8f62AefA082360b3A8D857952B3b8e
Eloqura Router	0x3f42823d998EE4759a95a42a6e3bB7736B76A7AE