Overview
Polar's Conversion API (CAPI) Enhancer strengthens the event data sent to advertising platforms like Meta and Google by enriching server-side signals with additional customer identifiers. This improves match rates, attribution accuracy, and ad algorithm performance — especially in a world where browser-based tracking is increasingly unreliable.
In this article:
What the CAPI Enhancer is and how it works
What to expect after enabling it (including event volume)
How deduplication works
Setup instructions for Meta, Google, and TikTok
Troubleshooting steps
FAQs
What is the CAPI Enhancer and Why It Matters
The CAPI Enhancer is a Polar feature that enriches your server-side conversion events before sending them to ad platforms. It attaches additional customer identifiers — such as hashed email, phone number, and external IDs — to increase the likelihood that platforms like Meta can match events to real users.
Why browser-only tracking is no longer enough
Cookie restrictions and browser limitations reduce pixel reliability
iOS privacy updates (ATT) limit user-level tracking
Ad blockers prevent pixel events from firing entirely
The result is that a significant portion of real purchases never reach your ad platform — leading to underreported conversions and weaker algorithm signals.
How the CAPI Enhancer helps
Match rate: More events are successfully linked to users
Attribution accuracy: Better visibility into campaign performance
Signal resilience: Less reliance on browser-based tracking
This ultimately leads to more reliable performance data and better decision-making for your marketing spend.
How the CAPI Enhancer Works
Event enrichment
Polar enhances your server-side events by attaching additional identifiers, including:
Email (hashed)
Phone number (hashed)
External IDs (e.g. customer IDs)
IP address and user agent
Which orders does Polar send events for?
Polar sends Purchase events to Meta (and other platforms) for all orders — not just orders that had a Meta ad touchpoint. This means customers who came through organic, direct, email, or any other channel will also have their purchase event sent.
This is intentional and correct behavior. Ad platforms use this complete signal to train their algorithms and improve attribution across all campaigns. Limiting events to only ad-attributed orders would significantly reduce signal quality.
What to expect after enabling CAPI: event volume
It's normal to see your Purchase event volume increase after enabling the CAPI Enhancer. This is not a sign of duplication — it's a sign of improved coverage.
Before CAPI, your event volume reflected only what the browser pixel was able to capture. The pixel misses a meaningful share of purchases due to ad blockers, iOS restrictions, and Safari ITP. The CAPI Enhancer recovers these lost signals server-side.
A healthy capture rate is typically 60–90% of your total Shopify order volume. If you want to verify your numbers are in a sensible range, compare your daily CAPI Purchase event volume against your actual order count in Polar.
How deduplication works
When both your browser pixel and the CAPI Enhancer are active, the same purchase could be reported by both. Meta (and other platforms) deduplicate these using the event_id field.
When your browser pixel fires a Purchase event and Polar sends the same event server-side, both must share an identical event_id for the platform to recognize them as the same event and count them only once.
If deduplication is working correctly, your event volume in Meta Events Manager should reflect real order activity — not inflated counts. You can verify this in Events Manager → Data Sources → your Pixel → Overview, where Meta shows a browser vs. server breakdown alongside a deduplication rate.
Common causes of deduplication failure:
The browser pixel is not explicitly setting a stable event_id
The event_id format differs between the pixel and the CAPI payload
The pixel is missing events entirely (e.g. headless checkout), resulting in CAPI sending net-new events with no browser counterpart to match against — this is expected and healthy, not an error
Setting Up and Using the CAPI Enhancer
Prerequisites:
To qualify for the CAPI Enhancer, the following conditions must be met:
Polar Pixel Installation: Ensure the Polar Pixel is correctly installed and tracking events.
Subscription: Confirm with your Customer Success Manager (CSM) that CAPI Enhancer is included in your current Polar plan.
Setup Process:
For Facebook:
Install Facebook Pixel: Ensure your FB Meta Pixel is installed on your Shopify store. Learn more here: Add a Meta pixel to your online store
Approve Account Access: We’ll request access to your Facebook accounts, which you will need to approve.
Manual Sync Creation: Our team will manually create the sync, refreshing every 15 minutes to push data back to Facebook.
For Google:
Approve Account Access: We’ll request access to your Google Ads accounts, which you will need to approve.
Manual Sync Creation: Our team will manually create the sync, refreshing every 15 minutes to push data back to Google.
Monitoring and Updates: We’ll closely monitor results for the first two weeks and provide weekly updates.
Troubleshooting Facebook/Meta CAPI
If your Meta events aren’t showing up or seem incomplete, you can use the Meta Pixel Helper Chrome extension to verify your setup and identify issues.
When to Use This
Run these checks if:
You’ve completed setup but no Meta events appear in Ads Manager
You’re seeing low event match quality or data discrepancies
You suspect deduplication issues between browser and server events
Add to Cart (ATC) and Purchase events are missing in Facebook Ads Manager after setting up Pixel + CAPI.
How to Troubleshoot
Install the Meta Pixel Helper
The Meta Pixel Helper is a Chrome extension, so you’ll need to use the Chrome browser.
Search for “Meta Pixel Helper” in the Chrome Web Store and install it.
Navigate to Your Website
Open your Chrome browser and visit the site where your Meta Pixel is installed.
Use the Pixel Helper
Click the Pixel Helper icon next to your address bar.
A pop-up will display all detected pixels and events on the page.
Look for event IDs, which confirm that deduplication is working correctly.
Identify Issues
A green icon indicates successful events.
Yellow or red icons show warnings or errors — such as events not firing or a missing pixel.
Review the message provided in the helper to identify the cause of the issue (e.g., “Pixel did not load”).
Common Causes for Missing Events
New or Unrecognized Domain Activity: If you recently added a tracker (Pixel + CAPI) to your domain, Meta may temporarily block events from being processed.
Domain Not on the Pixel’s Allow List: If your domain or the tracker’s redirect domain is not added to the Pixel’s Allow List, Meta will not accept events from it.
Verify Domain Permissions
Navigate to Facebook Events Manager → Data Sources → Select your Pixel → Settings → Traffic Permissions.
Add your primary domain and any relevant subdomains to the Allow List.
If using testing or preview domains, include them in the Allow List to ensure Meta accepts events from these URLs.
FAQs
Are There Any Risks in Using the Conversion API Enhancer?
Are There Any Risks in Using the Conversion API Enhancer?
No, there are no risks. Since the CAPI Enhancer sends additional event data to ad platforms, it only enhances the platform’s understanding of customer behavior, leading to improved ad performance.
Do I Need Technical Skills to Set It Up?
Do I Need Technical Skills to Set It Up?
Not at all! You will only need to install the Polar Pixel, our team will handle the manual sync setup and provide ongoing performance monitoring.
How Can I Get More Information or Assistance?
How Can I Get More Information or Assistance?
For more information about pricing or to schedule a demo, feel free to:
Contact your Customer Success Manager.
Reach out to us via the in-app chat.