Meta's Conversions API best practices: the reference every CAPI guide cites

Most CAPI advice you read online, this Vault included, is someone's interpretation of Meta's own rules. This page is the source those interpretations are built on: parameter-level guidance on what to send, how to hash it, deduplication logic against the browser pixel, and what actually moves Event Match Quality versus what is cosmetic.

Why it made the cut

Third-party CAPI guides go out of date or drift from Meta's actual requirements, and the gap only shows up when match quality quietly drops. This document is the canonical reference every serious implementer eventually opens to settle a dispute or debug a stuck EMQ score, whether the implementation runs through a custom server, a tag manager, or a gateway like Stape's.

How to run it

1. Read the parameter list and the hashing requirements before implementing anything.
2. Cross-check your existing CAPI setup against the deduplication guidance, since duplicate events between pixel and server-side calls are one of the most common EMQ problems.
3. Use the diagnostics in Events Manager alongside this document, not instead of it, to see which parameters are missing on your live events.
4. Revisit the page periodically; Meta updates it as CAPI parameters and requirements evolve.

Worth knowing

This is reference documentation, not a tutorial, so it assumes you already understand the concept of server-side events and are implementing or auditing a specific setup. It is also the one document in this space guaranteed to be current, since it is the product owner's own account of the product, unlike community guides that can lag a platform change by months.