> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fx.meme/llms.txt
> Use this file to discover all available pages before exploring further.

# Currency pairs

> The monetary relationship at the center of an FX market.

A currency pair expresses the value of one currency in another. EUR/USD is conventionally quoted as dollars per euro.

On FX, the relationship is implemented with specific token contracts. **EUR/USD** describes the currencies; **EURC/USDC** identifies the assets exchanged by the example market.

## A currency is more than its symbol

Tokens with the same ticker can have different issuers, contracts, networks, and transfer restrictions. FX identifies assets by their onchain addresses and the selected deployment.

For a market to be usable, the currency tokens must be supported and the connecting pool must have executable liquidity. A token appearing in a catalog does not by itself make it available for an FX launch.

## Why Arc

Arc gives applications a common environment for stablecoin payments and currency markets. USDC is its native gas asset, and EURC enables euro-denominated transfers. See [Arc's stablecoin model](https://docs.arc.io/arc/concepts/stablecoin-native-model).

FX uses that infrastructure to connect newly launched tokens to existing currency markets.

## Pool-derived pricing

The deployed R6 contracts use approved Uniswap v4 currency pools to price a launch's relationship between currencies.

The registry checks the pool's identity, initialized state, fee configuration, and active liquidity. It also tests quotes in both directions before admission. Starting prices account for each token's decimal precision.

The pool price is a **market price**, not an independent fiat reference. A small trade can have low price impact even when the pool's starting price is already distorted.

## The deployed currency pair

The mainnet registry has **USDC and EURC enabled**, with an admitted **EURC/USDC** currency pool on Uniswap v4. Its native LP fee is **0.05%**. See [currencies and pair](/developers/contracts#currencies-and-pair) for the token addresses and PoolKey.

The global launch gate is currently paused. Currency admission establishes the configured relationship; [release status](/reference/release-status) records when new token launches are available.

The same structure can extend to USD/JPY, EUR/JPY, USD/CAD, and other relationships as suitable currency tokens and markets are admitted. Those examples do not announce additional enabled pairs.

## Shared currency liquidity

A token launch adds its own TOKEN/currency pools. The connecting currency pool can already serve other traders and other FX launches.

A currency swap that never enters an FX token pool pays the currency pool's fees. It does not automatically generate FX's launched-token trading fee.

Continue with [launching a token](/guides/launch) or [trading across the triangle](/guides/trade).