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Custom stack - Meta Conversions API

Send every Custom stack event to the Meta Conversions API, server-side

Q: What is Event Match Quality (EMQ) and why does it matter?

EMQ is Meta’s score, from 0 to 10, for how reliably it can match a conversion event back to a Meta user. Higher EMQ gives Meta’s algorithm more signal to optimize against, and server-side delivery through CAPI typically raises it because events carry more match keys and are not blocked by browser restrictions.

Q: Will purchases be counted twice with the Pixel and the Conversions API both running?

No. Upstack sends a shared event_id on every server-side event, and Meta deduplicates against the matching browser Pixel event. As long as the Pixel ID in Upstack matches the Pixel ID firing in your storefront, deduplication is automatic.

Q: Which events does the Meta Conversions API receive?

PageView, ViewContent, AddToCart, InitiateCheckout and Purchase, each mapped to the Meta Conversions API event of the same name.

Q: Which customer parameters are sent to the Meta Conversions API?

Every event carries every available match key: em, ph, fn, ln, ct, st, zp and country, plus fbc, fbp and external_id. Personal data is hashed with SHA-256 before it leaves Upstack.

Q: How do I check that Custom stack events are reaching the Meta Conversions API?

Upstack marks the destination Healthy, and Events Manager lists the server events with a Server badge. Open your dataset’s Event Match Quality: it is scored per event type, and Meta takes 24 to 48 hours to score new events.

Each event is resolved to a person against a 750M+ device graph before it reaches the Meta Conversions API, with restored click IDs, deduplicated conversions and delivery you can audit.

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Upstack Signal showing Meta event match quality scores for each event

US device IDs in the graph: 750M+
Match rate on events: 90%+
Meta event match quality: 7.5+
Most brands are live: <20 min

How it flows

How a Custom stack event reaches the Meta Conversions API. Captured on the server, resolved to a person, then sent.

01 Capture

Captured from Custom stack

Not on the list? Send events to Upstack from any stack over webhook or direct post, with the same schema and the same resolution.

See the Custom stack integration

Custom stackWhat it sends

event_namewhatever you choose to call it
user identifiersany of email, phone, external ID
value / currencyif the event carries revenue
custom propertiesany attribute in your own schema

02 Understand

Resolved to one person before it leaves

Every Custom stack event is matched against a 750M+ device graph, so a phone browse and a desktop checkout resolve to one customer rather than two strangers.

How resolution works

Resolved before it is sent

IdentityMatched against a 750M+ device graph, so a phone browse and a desktop checkout resolve to one customer.
customer_typeNew or returning, resolved before send.
DeduplicationBrowser and server copies of the same purchase collapse on event ID, so nothing is counted twice.
Bot and fraud filteringAutomated traffic never reaches the model, because what you keep out of the training set matters as much as what goes in.

Ad platforms accept almost anything and tell you very little. These controls exist so you can see what was sent and what was accepted, rather than inferring it from a reporting gap.

03 Activate

Delivered to the Meta Conversions API

Forward deduplicated, identity-resolved conversions to Meta through the Conversions API, and give the model a customer instead of a session.

See the Meta Conversions API integration

Meta Conversions APIWhat it receives

em, ph (SHA-256)raise Event Match Quality
fbclid / _fbpcredit the click that drove it
external_idstable person across sessions
event_iddedupe against the browser pixel
value / currencyvalue-based bidding

Which events reach the Meta Conversions API

Each Upstack event is mapped to the Meta Conversions API event below before it is sent.

Upstack event	Sent to Meta Conversions API as	Key data on the event
Page view	PageView	URL, referrer, user agent
Product view	ViewContent	content_ids, content_type, value, currency
Add to cart	AddToCart	content_ids, value, currency
Checkout	InitiateCheckout	value, currency, num_items
Purchase	Purchase	value, currency, order_id, content_ids

Every event carries every available match key: em, ph, fn, ln, ct, st, zp and country, plus fbc, fbp and external_id. Personal data is hashed with SHA-256 before it leaves Upstack.

The catch

The freedom to name your own events is also the risk: an ad platform expects specific event names and parameter shapes, and anything outside that is accepted and ignored.

Mapping happens before send, not in the platform.

Where to check in the Meta Conversions APIDelivery you can audit

Events Manager your dataset Event Match Quality

Server events appear with a Server badge, and Event Match Quality is scored per event type.

What changes

What changes when Custom stack feeds the Meta Conversions API. Two gains on the Meta Conversions API side, two on the Custom stack side.

Meta Conversions API

Higher Event Match Quality

More hashed identifiers on every event (email, phone, external ID, click ID), so EMQ rises and Meta matches more of what you send.

Meta Conversions API

Pixel and CAPI, one install

One source of truth for both, with browser and server events deduplicated on event_id so purchases are never double-counted.

Custom stack

Any stack, any framework

Headless, custom checkout, native app or a platform we haven’t listed: if it can make an HTTP request, it can send to Upstack.

Custom stack

The same event schema

Custom events are resolved, filtered and forwarded exactly like a Shopify order.

Setup

Post directly from your backend so nothing depends on the browser.

You need admin access to Meta Business Manager.

Upstack dashboardExample

Custom stack Data source Connected

Facebook Advertising Destination Healthy

Read the full Meta Conversions API setup guide

01

Connect Custom stack

Not on the list? Send events to Upstack from any stack over webhook or direct post, with the same schema and the same resolution.
02

Add the Meta destination

Under Destinations, add Facebook Advertising with your Pixel ID (a 15 or 16 digit number) and a Conversions API token generated in Events Manager, which starts with EAA.
03

Check Event Match Quality

Upstack marks the destination Healthy, and Events Manager lists the server events with a Server badge. Open your dataset’s Event Match Quality: it is scored per event type, and Meta takes 24 to 48 hours to score new events.

FAQ

Questions about Custom stack and the Meta Conversions API.

What is Event Match Quality (EMQ) and why does it matter?

EMQ is Meta’s score, from 0 to 10, for how reliably it can match a conversion event back to a Meta user. Higher EMQ gives Meta’s algorithm more signal to optimize against, and server-side delivery through CAPI typically raises it because events carry more match keys and are not blocked by browser restrictions.

Will purchases be counted twice with the Pixel and the Conversions API both running?

No. Upstack sends a shared event_id on every server-side event, and Meta deduplicates against the matching browser Pixel event. As long as the Pixel ID in Upstack matches the Pixel ID firing in your storefront, deduplication is automatic.

Which events does the Meta Conversions API receive?

PageView, ViewContent, AddToCart, InitiateCheckout and Purchase, each mapped to the Meta Conversions API event of the same name.

Which customer parameters are sent to the Meta Conversions API?

Every event carries every available match key: em, ph, fn, ln, ct, st, zp and country, plus fbc, fbp and external_id. Personal data is hashed with SHA-256 before it leaves Upstack.

How do I check that Custom stack events are reaching the Meta Conversions API?

Upstack marks the destination Healthy, and Events Manager lists the server events with a Server badge. Open your dataset’s Event Match Quality: it is scored per event type, and Meta takes 24 to 48 hours to score new events.