Guide · Updated
How do the Meta Pixel and Conversions API work together?
Short answer
Run both, and make Meta count each purchase once. The Pixel records events in the browser; the Conversions API sends them from your server, which browser errors and ad blockers affect less. When both send the same purchase, give them the same event_name and event_id so Meta deduplicates it, then check Event Match Quality in Events Manager.
Ads Manager's conversion counts, and the signal Meta optimizes on, come from the events your Pixel and server send. When both send the same purchase without deduplication, Meta may count it twice and your conversion numbers run high. Event Match Quality, a score from 0 to 10 based on the last 48 hours of server events, shows how well those events match to Meta accounts. Start with the three posts below, then go to the question that fits your setup. For definitions of CAPI, deduplication and the Pixel, see the Meta ads glossary.
Start here
- How do I diagnose duplicate events between pixel and CAPI?
A ledger keyed on event name and ID for finding duplicate Pixel and CAPI events.
- Should events come from the browser or the server?
Which events should come from the browser, which from the server, and the key that joins them.
- Why is my Meta pixel not firing on Shopify?
Five steps for a pixel that isn't firing on Shopify, including how to remove a duplicate pixel safely.
How do I set up the Conversions API?
- How do I set up Meta Conversions API correctly?
Setup paths for Shopify and WooCommerce, the deduplication step, and which customer details to send.
- What should I check when setting up Meta Pixel and CAPI?
An ordered checklist for testing Pixel and CAPI events before you trust them.
- Should I use CAPI Gateway or a custom server-side setup?
How to choose between Meta's Conversions API Gateway and a custom server setup.
- What does server-side tracking actually cost to run?
What server-side tracking costs to run as volume grows, self-hosted or managed.
Why are my events duplicated, missing or not firing?
- What is event deduplication in Meta Ads?
What deduplication does with Pixel and CAPI events, and the mistakes that double-count purchases.
- Why does my Meta pixel show no recent activity?
The order to check when the Pixel shows no recent activity, from consent to the tag container.
- Does express checkout break my Meta pixel tracking?
How express checkout can hide purchases from the Pixel, and how to keep them tracked from the server.
Is my tracking good enough to optimize on?
- Should I check tracking before optimising Meta ads?
A quick health check of match quality, broken events and deduplication before you optimize.
- How do I turn quiz data into better Meta ad signal?
How consented quiz answers can feed CAPI with better customer matching.
- What is zero-party data and why does it matter?
Why data customers volunteer is a measurement asset, and what to collect.
Does my store platform set up Pixel and CAPI properly?
- Is Wix or Shopify better for running Meta ads to a D2C store?
Wix and Shopify compared on Pixel install, CAPI, catalog sync and customer data.
- Can you run Meta ads to a Wix landing page effectively?
Running Meta ads to a Wix landing page, including the Pixel and CAPI settings that decide tracking.
Sources: About Conversions API, About deduplication for Meta Pixel and Conversions API events, About event match quality (checked 1 October 2026).
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