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

# Postbacks overview

> Postbacks are server-to-server (S2S) HTTP calls that report conversions without cookies or JavaScript. Learn how Partnero supports both inbound postback tracking and outbound affiliate postbacks.

A **postback** is a server-to-server (S2S) HTTP request that reports a conversion — a sign-up or a sale — from one system to another. Because the request travels between servers, it is unaffected by ad-blockers, cookie restrictions, or cross-device journeys.

Partnero supports postbacks in **both directions**:

| Direction    | Feature                                                          | Who calls whom                           | Purpose                                                                                              |
| ------------ | ---------------------------------------------------------------- | ---------------------------------------- | ---------------------------------------------------------------------------------------------------- |
| **Inbound**  | [Postback URL tracking](/guides/postbacks/postback-url-tracking) | Your server → Partnero                   | Report sign-ups and sales to Partnero using a click ID, without the PartneroJS snippet or an API key |
| **Outbound** | [Affiliate postbacks](/guides/postbacks/affiliate-postbacks)     | Partnero → a partner's tracking platform | Notify a partner's own tracker (ad tracker, media-buying platform) when their referral converts      |

## How the two directions work together

Both directions share the same click record, created the moment a visitor clicks a partner's referral link:

1. **Click** — a visitor clicks a referral link such as `https://go.yourdomain.com/john?clickId=TRACKER_CLICK_ID`. Partnero records the click, captures any [trackable query parameters](/guides/postbacks/postback-url-tracking#trackable-query-parameters-sub-ids) (sub-IDs like `clickId` above), and generates its own **click ID** — appended to the landing URL on redirect links, or stored in a first-party cookie by PartneroJS on direct links.
2. **Conversion (inbound)** — your server calls the Partnero postback URL with that `click_id` when the visitor signs up or purchases. Partnero attributes the conversion to the right partner.
3. **Notification (outbound)** — Partnero fires the partner's affiliate postback, echoing the captured sub-IDs back to the partner's tracking platform so the conversion appears in their tracker too.

<Tip>
  You can use either direction independently. Inbound postback tracking is an alternative to [PartneroJS](/guides/tracking/javascript-tracking) and the [REST API](/guides/tracking/server-to-server); outbound affiliate postbacks work with any tracking method, including PartneroJS and billing integrations.
</Tip>

## When to use postbacks

* **Your partners run paid traffic** through tracking platforms and need conversions reported back automatically — use [affiliate postbacks](/guides/postbacks/affiliate-postbacks).
* **You want cookieless, blocker-proof attribution** without embedding an API key in any client — use [postback URL tracking](/guides/postbacks/postback-url-tracking).
* **You already use the REST API server-side** — you may not need inbound postbacks; compare in the [S2S tracking guide](/guides/tracking/server-to-server).

## Next steps

<CardGroup cols={2}>
  <Card title="Postback URL tracking" icon="arrow-right-to-bracket" href="/guides/postbacks/postback-url-tracking">
    Report sign-ups and sales to Partnero with a keyless postback URL
  </Card>

  <Card title="Affiliate postbacks" icon="arrow-right-from-bracket" href="/guides/postbacks/affiliate-postbacks">
    Send conversion notifications to your partners' tracking platforms
  </Card>
</CardGroup>