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

# Track completion

> Correlate a Hosted Page session with a Layerswap swap and confirm its final status.

To confirm the outcome of a swap started from the Hosted Page, check its status through the Layerswap API.

## Correlate with `externalId`

Add a unique `externalId` when you construct the Hosted Page URL:

```ts theme={null}
const sessionId = crypto.randomUUID();
const params = new URLSearchParams({
  to: 'BASE_MAINNET',
  toAsset: 'USDC',
  destination_address: userAddress,
  externalId: sessionId,
});
```

The created swap stores this value as `reference_id`. Store the session ID with the user action in your backend. When you list that user's swaps with `GET /swaps`, match `swap.metadata.reference_id` to your stored value and then track the matching swap by ID.

`reference_id` idempotency is unconfirmed, so generate a new value for each attempt and do not treat it as a duplicate-creation guard.

## Track by transaction hash

If your application knows the user's funding transaction hash, call:

```bash theme={null}
curl 'https://api.layerswap.io/api/v2/swaps/by_transaction_hash/0xTRANSACTION_HASH' \
  --header 'X-LS-APIKEY: YOUR_API_KEY'
```

Then poll `GET /swaps/{id}` until the swap reaches a terminal state. See [Track swaps](/api/track-swaps) and [Swap lifecycle & statuses](/concepts/swap-lifecycle).

## Let users inspect progress

Link users to the [Layerswap Explorer](https://layerswap.io/explorer) and let them search by swap or transaction identifier. This is useful for support and visibility, but your backend should still verify the API status before crediting a balance or fulfilling an order.