# Create a Trading Pair

## Overview

A trading pair lets two stablecoins trade against each other on the DEX. You create a pair for a
base token, and the token's quote token determines what it is priced against. Changing a quote token
is a two-step, time-delayed operation so the market has notice before pricing changes.

[See the Stablecoin Exchange specification](https://docs.tempo.xyz/protocol/exchange)

## Recipes

These recipes assume you have [set up a Tempo client](/tempo).

### Create a Pair

Create a new pair for a base token with [`dex.createPairSync`](/tempo/actions/dex.createPair).

:::code-group
```ts twoslash [example.ts]
import { client } from './viem.config'

const { receipt, ...pair } = await client.dex.createPairSync({
  base: '0x20c0000000000000000000000000000000000001',
})
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
// [!include ~/snippets/tempo/viem.config.ts:setup]
```
:::

### Prepare a Quote Token Change

Schedule a token's quote token with `token.prepareUpdateQuoteTokenSync`. This starts the mandatory
delay before the change can be finalized.

:::code-group
```ts twoslash [example.ts]
import { Actions } from 'viem/tempo'
import { client } from './viem.config'

const { receipt } = await Actions.token.prepareUpdateQuoteTokenSync(client, {
  token: '0x20c0000000000000000000000000000000000001',
  quoteToken: '0x20c0000000000000000000000000000000000002',
})
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
// [!include ~/snippets/tempo/viem.config.ts:setup]
```
:::

### Finalize a Quote Token Change

After the delay elapses, apply the prepared change with `token.updateQuoteTokenSync`.

:::code-group
```ts twoslash [example.ts]
import { Actions } from 'viem/tempo'
import { client } from './viem.config'

const { receipt } = await Actions.token.updateQuoteTokenSync(client, {
  token: '0x20c0000000000000000000000000000000000001',
})
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
// [!include ~/snippets/tempo/viem.config.ts:setup]
```
:::

## Best Practices

### Choose a Stable Quote Token

The quote token is the currency the base token is priced in, so pick a widely held, liquid
stablecoin. Pairs quoted in a thinly traded token are harder for takers to price and fill.

### Respect the Quote Token Delay

Updating a quote token is intentionally two-phase. Prepare the change, wait for the delay to elapse,
then finalize it. Plan migrations around this window so trading is not disrupted unexpectedly.

### Seed Liquidity After Creating a Pair

A new pair has no resting liquidity. Place [orders](/tempo/guides/stablecoin-exchange/orders) (or
provide [Fee AMM liquidity](/tempo/guides/stablecoin-exchange/fee-amm-liquidity)) so takers have
something to trade against.

## See More

<Cards>
  <Card icon="lucide:list-ordered" title="Place & Manage Orders" description="Seed a new pair with resting limit and flip orders." to="/tempo/guides/stablecoin-exchange/orders" />

  <Card icon="lucide:droplets" title="Provide Fee AMM Liquidity" description="Supply liquidity that powers stablecoin fee conversions." to="/tempo/guides/stablecoin-exchange/fee-amm-liquidity" />

  <Card icon="lucide:square-function" title="dex.createPair" description="Create a new trading pair for a base token." to="/tempo/actions/dex.createPair" />

  <Card icon="lucide:book-open" title="Tempo Docs: Stablecoin Exchange" description="Trading pairs, quote tokens, and pricing." to="https://docs.tempo.xyz/protocol/exchange" />
</Cards>