What is a Tracker?

A tracker (affiliate tracker, tracking platform) records paid clicks, routes traffic to landings and offers, accepts conversion postbacks, and reconciles spend with payout. It is the accounting layer for the source → click → conversion chain — not an ads manager and not site analytics.

In affiliate marketing and media buying, the traffic source shows spend and the partner network shows revenue. Without a tracker those two numbers live in different dashboards: you cannot tell which creative, sub_id, or GEO closed the offer. The tracker stores a click row with a unique click ID and later matches an incoming postback to that row.

What happens on the click

The ad hits a tracker campaign URL, not the offer first. The tracker writes time, IP, user-agent, GEO, device, and source tokens (often UTMs or ad-account macros). It mints a click ID and appends it to the landing or offer URL, e.g. sub1={clickid}. Then comes a redirect (302, meta, JS) or a locally hosted landing. Some products also do JS tracking on a third-party domain without a redirect; the requirement is the same: the click must have an ID before the conversion.

The same hop applies rules: GEO, device, browser, schedule, A/B split. That is routing, not “attribution magic.” If a filter sends the click to a safe page, the click row still has to exist — otherwise a later postback has nothing to match.

Postback, payout, and attribution

When the user submits a lead, deposit, or purchase, the network or advertiser calls the tracker URL. The request carries click ID, status (approved / pending / rejected), payout, sometimes a goal. The tracker finds the click and writes the conversion. In arbitrage, payout almost always follows last click inside the network: one click ID per payout. Meta or Google models (including data-driven) do not replace that payout loop.

Separate from inbound network postbacks is outbound S2S into the ad platform (Conversion API, offline conversions). That is an optimization signal for the ads account, not a substitute for ROI in the tracker. A landing pixel optimizes the account; offer money is counted on the postback.

Cost and reports

Clicks without cost yield CR and EPC, not ROI. Cost arrives as a manual CPM/CPC, a file, or an import from the ads account. If spend is not joined to the same campaign and period as payout, the report lies in both directions. Usual cuts: campaign, offer, landing, source, GEO, device, sub_id, hour. Click and postback logs matter when “the ads account has conversions the tracker does not,” or the reverse.

Self-hosted vs cloud

By hosting, trackers split into self-hosted (you install on a VPS; data stays with you) and cloud SaaS (the vendor hosts; billing often follows event volume). The first group includes Keitaro, Binom, and ATracker; the second includes Voluum, RedTrack, and BeMob. The class is the same: click, routing, postback, report. License, limits, who patches the server, and where raw logs live differ. Brand-by-brand comparison belongs on /compare, not in the class definition.

What a tracker is not

Not Google Analytics or Yandex Metrica. A site tag counts sessions and events on your domain. A tracker counts the paid click and the offer payout. A GA4 property does not replace a tracker.
Not an MMP. A mobile measurement partner covers app install/in-app for UA accounts. Grey-web CPA offers use a different loop: click ID + network postback.
Not the Facebook/Google ads account. The account optimizes its own campaigns under its own model. The tracker joins several sources to one partner network.
Not an affiliate network. The network issues the offer and pays. The tracker is the buyer’s or team’s ledger.