> ## 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. # Postback URL tracking (inbound S2S) > Track affiliate sign-ups and sales with a keyless postback URL. Partnero appends a click_id to every referral visit; your server sends it back at conversion — no cookies, no JavaScript, no API key. Postback URL tracking lets your server report conversions to Partnero using a **click ID** instead of cookies or the PartneroJS snippet. Partnero appends a `click_id` query parameter to every referral-link visit; you store it and send it back when the visitor signs up or purchases. Unlike the [REST API](/guides/tracking/server-to-server), the postback URL requires **no API key** — attribution is scoped by your program's public ID and a valid click ID. ## How it works 1. **A visitor clicks a partner's referral link.** Partnero records the click and generates a unique click ID. 2. **Your site receives the click ID** — as a `click_id` query parameter on the landing URL, in the `partnero_click_id` cookie set by PartneroJS, or as a response from the click registration API (see [Where the click ID comes from](#where-the-click-id-comes-from)). 3. **You store the `click_id` value** — in your session, database, or any storage that survives until conversion. 4. **Your server calls the postback URL** with that `click_id` when the visitor converts. Partnero matches it to the click and attributes the sign-up or sale to the right partner. Because the browser plays no part at conversion time, attribution survives ad-blockers, blocked cookies, Safari ITP, in-app browsers, and cross-device flows. ## Where the click ID comes from Partnero generates a click ID in three ways. All three create the same click record — pick whichever fits your setup. ### 1. Referral link redirect If your referral links go through a connected tracking domain (for example `go.yourdomain.com/john`), the redirect automatically appends the click ID to the destination URL: ``` https://your-site.com/?click_id=Ab3xK9 ``` Read it from the query string on your landing page. Nothing else to set up. ### 2. PartneroJS (direct links) If referral links point straight at your site (for example `https://your-site.com/?aff=john`) there is no redirect, so the [PartneroJS snippet](/guides/tracking/javascript-tracking) registers the click for you. On a referred visit it requests a click ID and stores it in a first-party cookie: ``` partnero_click_id=Ab3xK9 ``` Read the cookie server-side at conversion time. The snippet also injects the click ID as a hidden `partnero_click_id` input into any `
` form. If the visitor arrived through a redirect that already carries a `click_id` parameter, the snippet reuses it instead of registering a duplicate click. ### 3. Click registration API Use this when neither of the options above fits: your referral links point straight at your site, but you don't run PartneroJS — for example a backend-only integration, a mobile app, or a server-rendered site without the snippet. Your own code registers the click and receives the click ID in return. When a visitor arrives through a referral link like `https://your-site.com/?aff=john`, read the partner's referral key (`john`) from the URL — the same way you would for any referral tracking. Send the referral key to the click registration endpoint. `{pub_id}` is your program's public ID, shown on the Postbacks page. No API key is needed. ```bash theme={null} curl -X POST "https://api.partnero.com/pub/v1/s2s/clicks/{pub_id}" \ -H "Content-Type: application/json" \ -d '{"partner": "john", "url": "https://your-site.com/?aff=john&clickId=TRACKER_CLICK_ID"}' ``` | Parameter | Required | Description | | --------- | -------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | `partner` | Yes | The partner's referral key captured in step 1 | | `url` | No | The full landing URL. If it contains any [trackable query parameters](#trackable-query-parameters-sub-ids) (like `clickId` above), their values are captured as sub-IDs | A successful registration returns the click ID: ```json theme={null} {"status": 1, "click_id": "Ab3xK9"} ``` Store it with the visitor's session or user record, and send it back in the [postback](#the-postback-endpoint) when they convert. Register one click per referred landing — not on every page view. Like the postback endpoint, this endpoint responds `200` with an empty JSON body on any failure (unknown program, unknown partner, or postback tracking disabled), and requests are rate-limited to 60 per minute per IP. ## Enable postback tracking 1. In the Partnero dashboard, open **Program → Integration → Postbacks** (affiliate programs). 2. In the **Inbound S2S tracking** section, switch on **Postback (S2S) tracking**. The section then shows your program's unique postback endpoint and copy-ready example requests. Once enabled, referral-link redirects automatically start carrying the `click_id` parameter, PartneroJS starts registering clicks on direct referral visits, and the click registration API becomes active. ## The postback endpoint ``` GET|POST https://api.partnero.com/pub/v1/s2s/postback/{pub_id} ``` * `{pub_id}` is your program's public ID — the same ID used by the PartneroJS snippet. You don't need to build the URL yourself: the Postbacks page shows your program's complete endpoint, ready to copy. * Both `GET` (query parameters) and `POST` (form or JSON body) are accepted. * **No authentication token is required.** Requests are matched by the `click_id` value; requests with an unknown `click_id` are silently ignored. * The endpoint always responds `200 OK`, whether or not the postback matched a click. This is intentional: it prevents third parties from probing for valid click IDs. Two events are supported, selected with the `event` parameter. ### Register a sign-up (`customer_create`) | Parameter | Required | Description | | ---------- | -------- | -------------------------------------------------------------- | | `click_id` | Yes | The click ID captured from the landing URL | | `event` | Yes | `customer_create` | | `key` | Yes | Your unique identifier for the customer (user ID, email, etc.) | | `email` | No | Customer email | | `name` | No | Customer name | ```bash theme={null} curl "https://api.partnero.com/pub/v1/s2s/postback/{pub_id}?click_id=Ab3xK9&event=customer_create&key=user_512&email=jane@example.com" ``` The customer is created and attributed to the partner from the click record. ### Register a sale (`transaction_create`) | Parameter | Required | Description | | -------------------------- | -------- | ----------------------------------------------------------------------- | | `click_id` | Yes | The click ID captured from the landing URL | | `event` | Yes | `transaction_create` | | `key` | Yes | Your unique transaction identifier (order ID, invoice ID) | | `amount` | Yes | Transaction amount | | `action` | No | Transaction action label (e.g. `sale`) | | `customer[key]` | No | Customer key; defaults to the customer already linked to the click | | `options[create_customer]` | No | Set to `true` to create the customer on the fly if it doesn't exist yet | ```bash theme={null} curl "https://api.partnero.com/pub/v1/s2s/postback/{pub_id}?click_id=Ab3xK9&event=transaction_create&key=order_1201&amount=49.90&options[create_customer]=true" ``` The transaction flows through the normal pipeline — commission calculation, webhooks, notification emails, and [outbound affiliate postbacks](/guides/postbacks/affiliate-postbacks). If you register the sign-up with `customer_create` first, you can skip `options[create_customer]` on the sale — the click record already knows the customer. ## Trackable query parameters (sub-IDs) Partners who run traffic through their own tracking platforms append extra parameters to referral links — typically their tracker's click ID or campaign sub-IDs: ``` https://go.yourdomain.com/john?clickId=TRACKER_CLICK_ID&affS1=campaign-42 ``` To capture these values, define the parameter names under **Program settings → Referral link customization → Trackable query parameters**. At click time Partnero stores the values on the click record. They are then available: * in click analytics, and * as placeholders in [affiliate postbacks](/guides/postbacks/affiliate-postbacks#placeholders), so the partner's tracker gets its own click ID echoed back at conversion. You can add up to 50 parameter names per program. Common industry names (`clickid`, `sub1`, `aff_sub`, `s1`, …) are available as one-click suggestions in the dashboard. ## Storing the click ID Read `click_id` from the landing URL (redirect setups) or from the `partnero_click_id` cookie (PartneroJS setups) and persist it the same way you would a referral key: ```javascript theme={null} app.get('/', (req, res) => { const clickId = req.query.click_id || req.cookies.partnero_click_id; if (clickId) { req.session.partneroClickId = clickId; } res.render('home'); }); ``` ```javascript theme={null} const clickId = new URLSearchParams(window.location.search).get('click_id'); if (clickId) { fetch('/api/track-landing', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ click_id: clickId }) }); } ``` ```javascript theme={null} const url = new URL(`https://api.partnero.com/pub/v1/s2s/postback/${PUB_ID}`); url.search = new URLSearchParams({ click_id: session.partneroClickId, event: 'transaction_create', key: order.id, amount: order.amount, 'options[create_customer]': 'true' }); await fetch(url); // no API key needed ``` ## Postback URL tracking vs. REST API | | Postback URL *(this guide)* | [REST API](/guides/tracking/server-to-server) | | ------------------- | --------------------------------------------------------- | ------------------------------------------------ | | Authentication | None — matched by `click_id` | `Authorization: Bearer` API key | | Attribution carrier | Partnero-generated click ID | Referral key you capture from the URL | | Response on failure | Always `200` (silent) | Standard HTTP errors | | Best for | Simple keyless integration, tracker-style postback setups | Full control, richer customer/transaction fields | ## Checklist 1. Enable **Postback (S2S) tracking** under **Program → Integration → Postbacks**. 2. Store the `click_id` from the landing URL between click and conversion. 3. Call the postback endpoint with `event=customer_create` at sign-up. 4. Call it with `event=transaction_create` at purchase. 5. Optionally, define **trackable query parameters** so partner sub-IDs are captured too. ## Frequently asked questions No. Requests are scoped by your program's public ID and matched by the `click_id`; unknown click IDs are ignored. To avoid leaking which click IDs are valid. To debug deliveries, open **Logs** in the Inbound S2S tracking section of the Postbacks page — every incoming request is recorded with its parameters and outcome (`success`, `failed`, or `ignored`). Yes. GET takes query parameters; POST accepts the same fields as form data or JSON. Both events are safe to retry. `customer_create` is idempotent — if a customer with the same `key` already exists, the request succeeds and returns the existing customer. Transactions are deduplicated by your transaction `key` — send a unique order or invoice ID per sale. ## Next steps Echo conversions back to your partners' tracking platforms API-key-based server-side tracking with full field control