Facebook Pixel vs Conversions API

The Facebook Pixel and the Conversions API (CAPI) do the same job, sending your website events to Meta, but from two different places. The pixel sends from the visitor's browser. CAPI sends from your server.

The short version: this is not a choice between them. You run both, together, and they cover each other's gaps. This page explains the difference, where the pixel falls short, and why running both is the setup Meta actually recommends.

For the full picture of how these events train Meta's ad system, see our guide to the Meta Conversions API.

What the Facebook Pixel is

The pixel is a small piece of code on your website. When someone views a page, adds to cart, or buys, the pixel fires from their browser and reports that event to Meta.

It has been the standard way to track Facebook ads for years, and for a long time it was enough. The problem is that everything the pixel relies on, the browser, cookies, and JavaScript, is exactly what modern privacy changes have locked down.

What the Conversions API is

CAPI sends the same events, but from your server instead of the browser. The visitor's browser is never in the loop, so there is nothing to block, clear, or lose in transit.

Because the event comes from your server, it can carry richer information. Your server already knows the customer's email and order details at checkout, so it can pass more identifying data to Meta (all securely hashed) than a browser usually can. That matters for matching, which we cover below.

Side by side

Facebook PixelConversions APISends fromVisitor's browserYour serverBlocked by ad blockersYesNoAffected by iOS / ATTYesNoAffected by cookie restrictionsYesLargely noData it can accessLimited to the browserFull server-side dataReliabilityDrops a share of eventsDelivers consistentlySetupAdd code to your siteNeeds a server connection

Where the pixel falls short

The pixel only works when the browser cooperates, and increasingly it does not:

• Ad blockers stop the pixel firing at all.

• Apple's privacy prompt (ATT) blocks tracking on iPhones unless the user opts in, and most do not.

• Browser cookie restrictions limit what the pixel can store and read.

Add these up and the pixel now misses a large share of real conversions, often a quarter or more. Those are not just missing report numbers. Every lost event is a conversion Meta's algorithm never learns from, which makes its targeting worse and your ads more expensive.

Why you run both

Running CAPI does not replace the pixel. The two work as a pair.

The browser sends what it can through the pixel. CAPI sends the same events server-side and fills the gaps the pixel lost. A shared event ID lets Meta recognise when both methods report the same action, so the sale is only counted once. This is called deduplication, and it is why running both is safe rather than double-counting.

The result is more complete data than either method delivers alone: the pixel's reach plus CAPI's reliability.

So which should you use?

Both. The pixel alone leaves too much on the table, and CAPI alone misses some browser-only signals. Together they give Meta the fullest possible view of what happens on your site.

The catch has always been setup. Adding a pixel is easy. Connecting CAPI traditionally meant server code, which put it out of reach for anyone on a no-code platform without a developer.

That is the gap PixelFlow closes. It runs the Conversions API alongside your pixel, with deduplication handled for you, on Webflow, Framer, Squarespace, WordPress, and more, without you touching code.

Set up Facebook CAPI without code →

Related reading

• The Meta Conversions API, explained

• Why do you need the Conversions API?

• How does the Conversions API work?