Full Answer

The mismatch is structural and expected — not a bug in your implementation. Every browser-side tracking pixel, including TikTok's, operates within constraints that make 100% capture impossible in 2026.

The largest contributor is iOS App Tracking Transparency. When an iOS user opts out of tracking in the ATT prompt, TikTok loses the ability to match their ad interaction to a subsequent website conversion. Apple reports approximately 96% of US iOS users opt out. For WooCommerce stores where iOS users represent 40–60% of mobile traffic, ATT alone can hide 25–40% of mobile conversions from TikTok's attribution.

Ad blockers remove TikTok's pixel script before it can execute. The script loads from analytics.tiktok.com, a domain present on every major blocklist. When blocked, no events fire for that visitor's entire session. This affects roughly 15–25% of desktop traffic depending on audience demographic.

The diagnostic step is straightforward: export WooCommerce orders for a specific date range and count total purchases, then compare against TikTok Events Manager for the same period. The difference is your tracking gap. If TikTok shows 65 purchases and WooCommerce shows 100, your capture rate is 65%. TikTok Events API sends conversion events server-to-server, bypassing browser blocking entirely and using the same event schema as the pixel. Deduplication between pixel and Events API prevents double-counting, and the typical result is a 20–30 percentage point improvement in capture rate.