# CTA links and redirects

CTA links connect a campaign email, ad, or landing page button to the active promo state.

## Participant reference

Use `pf_ref` when linking from email or another identified channel.

```html
<a href="https://acme.plandalf.dev/p/early-bird?pf_ref={{subscriber.email}}">
  Get the launch price
</a>
```

The SDK also captures `pf_ref` from the current page URL so later checkout calls can include attribution context.

## Checkout button with promo

```html
<button
  data-plandalf-present="summit-ticket"
  data-plandalf-apply-promo="early-bird"
>
  Buy now
</button>
```

## External destination

Some campaigns send visitors to an external sales page first, then open Plandalf checkout from that page. Keep the same `pf_ref` value on the URL so attribution stays connected.

```html
<a href="https://example.com/sales-page?pf_ref={{subscriber.email}}">
  Read the offer
</a>
```

## Related docs

-   [Embedded promos](https://plandalf.com/docs/product-guides/promos/embedded-promos)
-   [Hosted landing pages](https://plandalf.com/docs/product-guides/promos/hosted-landing-pages)
-   [Affiliates attribution](https://plandalf.com/docs/product-guides/affiliates/attribution)

Source: https://plandalf.com/docs/product-guides/promos/cta-links