A customer added to cart and didn't finish — an abandoned cart is one of the strongest signals of purchase intent. If you measure it, you can turn it back into a sale. Here's how to reliably capture and use it.
What an abandoned cart is for measurement
An abandoned cart is when add_to_cart (or begin_checkout) happens but not purchase. Measuring it means capturing these micro-conversions — see measuring the full funnel.
What to use it for
- Remarketing. Reach with ads those who added to cart and didn't finish.
- Email / SMS flows. Remind about the cart (if you have email with consent). It relates to flow triggers in general.
- Diagnostics. A high abandonment rate at a certain step shows where people drop off.
Why server-side
- Reliable capture. When client-side loses add_to_cart to an ad-blocker, the remarketing audience is patchy. Server-side captures it more reliably.
- Longer identification. For remarketing to reach someone who returns days later, identity must persist — see ITP and lost conversions.
- Reliable flow triggers. An email flow fires only when the event arrives — server-side raises the chance it does.
What to watch
- Distinguish add_to_cart and begin_checkout — they're different intent stages.
- Only send email reminders with consent.
- Measure the recovery rate too (how many abandoned carts come back), not just the abandonment count.
Summary
An abandoned cart is an intent signal you can win sales back from — via remarketing and flows. The key is to capture it reliably and keep identity, which server-side tracking does better than client-side. More in the complete guide.