What is CAPI? The Conversions API and Why You Need It
Also known as: Conversions API, Conversion API, Meta CAPI, server-side API
Short answer
CAPI is a way to send conversion events straight from your server to an ad platform, without depending on the visitor browser. Because it bypasses the browser, CAPI is not blocked and still works for sales that close on WhatsApp, over the phone, or in a shop.
The simple way to think about it
A pixel is a note you hand the customer to carry to the ad platform. If they forget, or the road is blocked, the note never arrives.
CAPI is you posting that note yourself, directly, from your own office.
Side by side
| Pixel | CAPI | |
|---|---|---|
| Sent from | Visitor browser | Your server |
| Can be blocked | Yes | No |
| Sees WhatsApp closes | No | Yes |
| Sees in-shop sales | No | Yes |
| Can be sent days later | No | Yes |
| Needs page installation | Yes | No |
Why this matters especially in Southeast Asia
Many sales never reach a checkout page. Someone clicks an ad, moves to WhatsApp, asks questions, then transfers the money. Without server-side sending, the ad platform sees the click and nothing after it. The auction then learns to find people who like clicking, not people who pay.
Conditions for CAPI to be useful
- Send the same event marker the website code uses, so nothing is counted twice.
- Include the transaction value, so the platform chases larger sales.
- Include every identifier you have: the Click ID, and customer details as standard one-way codes.
- Never send values your system already encrypted as identifiers. They match nothing.
- Send inside the platform time limit, usually days to a few tens of days.
Frequently asked questions
- Why do I need CAPI when I already have a pixel?
- A pixel only sees the website and can be blocked. CAPI sees whatever your system knows, including sales that close away from the website. For businesses that close on WhatsApp, CAPI is not an add-on but the main path.
- Does CAPI cause conversions to be counted twice?
- It can, if the pixel and CAPI send the same event without matching markers. Send an identical event marker from both paths, so the platform can merge them into one conversion.
- Does every platform have a CAPI?
- Every major platform has a server-side sending path under its own name. Meta calls it the Conversions API. Google, TikTok, and LinkedIn have equivalents. The concept is the same: your server sends, not the browser.
- What must be sent with a CAPI event?
- The event time, the event type, the transaction value and currency, an event marker for merging, and whatever identifiers exist, such as a Click ID and customer details as one-way codes.
Related terms
Konektor guides
Your ad numbers are only as accurate as the data behind them
Konektor captures the Click ID and sends conversions that close on WhatsApp, over the phone, or in a shop back to the ad platform.