# Traffic source postback

Before adding S2S postback, look for the answers:

  1. Does the traffic source support S2S postbacks?
  2. What placeholders traffic source allows using?
  3. Where to get personal Postback URL?

Paste your personal Postback URL to Postback URL field.

Replace the value of click ID to {external_id} (it's a placeholder).

For example, your personal Postback URL is https://adnetwork.com/postback?aff=99&uid=CLICK_ID.

The final URL as follows: