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Conversions API (CAPI)

Definition

The Meta Conversions API (CAPI) is a server-side tracking solution that sends conversion data directly from your server to Meta's servers. Unlike the browser-based Pixel, CAPI is not affected by ad blockers, cookie restrictions, or iOS privacy changes, making it essential for accurate conversion tracking and ad optimization in the modern privacy landscape.

How Conversions API Works

CAPI sends HTTP POST requests from your server to Meta's Graph API endpoint with event data. Each request includes the event name (Purchase, Lead, etc.), user parameters for matching (hashed email, phone, IP, user agent), event parameters (value, currency, content IDs), and a timestamp. Meta matches this server-side data against its user database to attribute conversions to ad clicks and views. CAPI data is more reliable than Pixel data because it is not subject to browser-level interference.

Implementation Options

There are several ways to implement CAPI. Direct integration involves coding API calls into your server-side application. Partner integrations (Shopify, WooCommerce, WordPress plugins) offer no-code setup. Customer data platforms like Segment or Tealium can route events to CAPI. Meta's Conversions API Gateway provides a managed server-side solution on AWS. Choose based on your technical capabilities: partner integrations for simplicity, direct integration for maximum control and customization.

Deduplication with the Pixel

When using both Pixel and CAPI (recommended), you must deduplicate events to prevent double-counting. Assign the same unique event_id to both the Pixel event and the CAPI event for the same user action. Meta automatically deduplicates events with matching event_id and event_name within a 48-hour window. Without deduplication, your conversion counts will be inflated, your optimization will be skewed, and your reported ROAS will be artificially high.

CAPI Monitoring with AdWhiz

AdWhiz checks your Conversions API implementation for data quality, match rates, and deduplication accuracy. The audit identifies events where CAPI and Pixel data diverge significantly, indicating potential tracking issues. High event match quality (EMQ) scores are essential for good ad optimization, and AdWhiz monitors these scores and provides recommendations to improve data quality and user matching parameters.

Frequently Asked Questions

Yes. With iOS App Tracking Transparency and browser ad blockers, the Pixel alone misses a significant portion of conversions. Meta reports that adding CAPI to Pixel can recover 15-30% of lost conversion data. This improved data leads to better ad optimization, more accurate reporting, and lower costs.

Difficulty depends on your platform. Shopify, WooCommerce, and major e-commerce platforms offer one-click CAPI integrations. Custom websites require developer time to implement API calls. Meta's Conversions API Gateway provides a managed solution. Most businesses can get CAPI running within a few hours using partner integrations.

Event Match Quality (EMQ) is Meta's score (1-10) for how well your CAPI events can be matched to Meta user profiles. Higher EMQ means better attribution and optimization. Improve EMQ by sending more user parameters: hashed email, phone number, first/last name, city, state, zip code, and external ID alongside each event.

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