iOS 14+ broke Meta Pixel client-side attribution in 2021. Five years later, most agencies STILL don’t have proper Conversions API (CAPI) setup. Here’s what’s actually working in 2026.
The problem in one sentence
Apple’s App Tracking Transparency forced Meta to stop tracking what iOS users do after they leave Facebook/Instagram. Click-through conversions, time-windowed attribution, and lookalike audiences all suffered.
The fix: Conversions API (CAPI)
Server-to-server tracking that bypasses the iOS 14+ restrictions. Send the conversion data directly from your server to Meta. Most agencies skip this because it’s “harder than it sounds.” It’s not — most modern platforms have CAPI built in.
How to set up CAPI properly
- Shopify: Install Meta’s official Shopify app + enable CAPI in the setup wizard. Done.
- WooCommerce: PixelYourSite Pro plugin handles CAPI.
- Custom sites or higher volume: Server-side GTM via Stape.io ($20/mo) or self-hosted on Google Cloud Run.
The dedup gotcha
If you send the same event via both Pixel (client) and CAPI (server), Meta will count it twice. Use the event_id parameter to deduplicate. Most setup wizards handle this — verify in Meta Events Manager → Test Events.
Match quality matters
Send hashed email + phone + name + IP + user agent with every CAPI event. Better match quality = better attribution + better ad delivery + better LAL audiences.
What this fixes
- ~30-50% of conversions previously lost are recovered
- ROAS reporting matches reality (no more “Meta says we made $50K, GA says $30K”)
- Lookalike audiences work again (better seed data)
- Better bid optimization (Meta has more data to work with)
If your agency hasn’t set this up, that’s why your Meta ROAS feels disappointing. Get a free audit →