What is a pixel tracker?
A pixel is a small piece of code from an ad platform that runs on your store. Meta has one, TikTok has one, so do Google, Snapchat and Pinterest. When a visitor views a product, adds it to the cart or buys it, the pixel sends an event back to that platform.
The ad platform uses those events for three things. It reports results in your ads manager, so you can see which ads sell. It feeds its delivery algorithm, so it learns which kind of person buys from you. And it builds audiences for retargeting and lookalikes.
A pixel tracker is the tool that makes sure those events actually arrive, with enough detail to be matched to the right ad. At its simplest it installs the pixels for you. A better pixel tracker also sends the events from a server, keeps the ad click so later purchases still count, and shows you per ad what it cost and what it sold.
Why browser pixels miss sales
A browser pixel only works when the buyer's browser runs the script and lets it talk to the ad platform. On a modern phone, that fails more often than most store owners expect. These are the usual causes:
- Ad blockers and privacy browsers block the pixel script or its network requests.
- Safari and iOS shorten the life of cookies set by scripts, so a buyer who comes back after a few days looks like a new visitor.
- Cookie banners: if the buyer doesn't accept marketing cookies, the pixel may not run at all.
- In-app browsers in Instagram, Facebook and TikTok keep the session only briefly. Many buyers switch to Safari or Chrome to pay, and the click is lost.
- The thank-you page never loads: the buyer closes the tab after paying, pays through a redirect that doesn't come back, or the page loads too slowly.
- Buyers who switch devices: they click the ad on their phone and buy on a laptop that night.
What missed sales cost you
The obvious cost is a wrong number. Your ads manager shows a lower ROAS than you really earn, and you make decisions on it.
The bigger cost is what the algorithm learns. Meta and TikTok optimise toward the people who send purchase events. If a third of your buyers never show up, the platform learns from a smaller, skewed group. It spends your budget less well, and ads that actually make money can look like they break even, so you switch them off.
Retargeting and lookalike audiences shrink as well, because they're built from the same incomplete data.
A simple example. Say an ad set costs €1.000 in a week and really brings in €2.500 in sales. If the pixel only reports €1.700 of that, Ads Manager shows a ROAS of 1,7 instead of 2,5. With a margin that needs a ROAS of 2 to break even, the ad set looks like it loses money, and it's the first thing you'd cut.
Server-side tracking: the part that fixes it
Every big ad platform now has a server API next to its browser pixel: the Meta Conversions API, the TikTok Events API, Google's conversion uploads for Google Ads and the GA4 Measurement Protocol, the Snapchat Conversions API and the Pinterest Conversions API. These accept events from a server instead of a browser.
A server-side pixel tracker uses them. When an order is paid, your store tells the tracker, and the tracker sends the purchase to each ad platform. No browser is involved, so ad blockers and closed tabs don't matter for that event.
The browser pixel still runs next to it. Both copies carry the same event id, so the platform counts the sale once (this is called deduplication). The browser copy brings cookie data, the server copy makes sure the sale arrives.
What to look for in a pixel tracker
Plenty of apps call themselves a pixel tracker. Some only paste pixel codes into your theme. If you're comparing, these are the questions worth asking:
- Does it send purchases server-side, from your store's order data, or only from the browser?
- Does it save the ad click (fbclid, ttclid, gclid, ScCid) when the visitor lands, and for how long? A buyer who returns after two weeks should still count.
- Does it send hashed email and phone? That's how platforms recognise a buyer when cookies are gone.
- Does it deduplicate browser and server events with one event id, so sales aren't counted twice?
- Which ad platforms does it cover? Most stores run at least two.
- Can you see, per order, what was sent and whether it arrived? Failed sends should be retried by themselves.
- How is it priced: flat, per order, per event or per tracked revenue? Check what happens to the bill in your best month.
- Does it work on your platform? Many trackers are Shopify-only.
What a pixel tracker is, and isn't
No tool tracks every buyer. If someone declines tracking in your cookie banner, you should respect that. If a buyer never clicked an ad, there's no click to link. And each ad platform decides for itself how many of the purchases it receives it can tie to a specific person and ad.
What a server-side pixel tracker does is make sure every paid order reaches the platforms you connected, with as much matching data as the buyer allowed. That's where the name 99,9% Tracking comes from: it's the share of paid orders we deliver, not a promise about what each platform attributes.
Pixel trackers and attribution suites overlap, but they're built for different jobs. A pixel tracker's main job is outward: getting every sale back to the ad platforms so their algorithms learn from the real numbers. An attribution suite looks inward: it builds its own reports, often with several attribution models, cohorts and forecasts, for a team that analyses marketing full time.
Most stores spending a few thousand a month on ads get the most value from the first job. The algorithm does the heavy lifting on Meta and TikTok, and it can only do that with complete purchase data. A clear view of spend, sales and ROAS per ad then tells you where to put the next euro. If you later need deeper analysis, a suite can sit next to a pixel tracker without conflict.
How Settl's pixel tracker works
Settl's 99,9% Tracking is a server-side pixel tracker for Shopify and WooCommerce. On Shopify you add one line to your theme. On WooCommerce you install the Settl plugin and paste your connection code. Your checkout stays as it is.
When a visitor lands from an ad, Settl saves the click (fbclid and fbp for Meta, ttclid for TikTok, gclid for Google, ScCid for Snapchat, epik for Pinterest, twclid for X, msclkid for Microsoft Ads, rdt_cid for Reddit, plus UTM tags if you use them) first-party, on your own store, and keeps it for 90 days. Page views, product views, add to cart and checkout go out from the browser and from our server, with the same event id.
When an order is paid, Shopify or WooCommerce tells Settl right away, and an hourly check picks up anything that slipped through. The purchase goes to Meta, TikTok, Google (GA4, plus a direct upload to Google Ads), Snapchat, Pinterest, X, Microsoft Ads and Reddit with the value, the currency, the saved click and hashed email and phone. If a platform doesn't accept it the first time, it's retried automatically, and you see the status per order. An hourly health check e-mails you if a platform starts failing, a token expires or orders stop arriving.
Settl also connects to your Meta, TikTok, Google Ads, Snapchat and Pinterest ad accounts. The dashboard shows spend, sales and ROAS per ad, with advice on which ads to scale and which to switch off, plus a live view of who's on your store on a map.