pixel: add ensure fbc fallback

src/lib/MetaPixel.svelte

@@ -1,285 +0,0 @@
-<!-- @component
-MetaPixel integrates the Meta (Facebook) Pixel into your Svelte application,
-allowing you to track page views and custom events while respecting user consent
-for tracking. The component manages the lifecycle of the Meta Pixel script and
-PixelControl interface.
-
-The PixelControl class also allows you to directly manage multiple Pixel
-instances and handle event tracking with optional test event codes without
-using the MetaPixel component.
--->
-
-<script lang="ts" module>
-	export type PixelControlOptions = {
-		/**
-		 * if provided, events fired will always have this code attached
-		 * to prevent them from polluting real analytics data.
-		 */
-		testEventCode?: string;
-		/** Advanced matching data */
-		advancedMatching?: AdvancedMatching;
-		/** Initialization options */
-		initOptions?: InitOptions;
-	};
-
-	export class PixelControl {
-		private _pixelID: string;
-		private _testEventCode?: string = undefined;
-		private _trackingManager: MaybeGetter<TrackingManager | undefined>;
-
-		private static _baseLoaded: boolean = false;
-		private static _registeredPixels: Record<string, PixelControl> = {};
-
-		/** Indicates whether the Meta Pixel base script has been loaded. */
-		static get baseLoaded(): boolean {
-			return this._baseLoaded;
-		}
-
-		/**
-		 * Ensures that the Meta Pixel base has been loaded before
-		 * allowing further operations.
-		 * @throws Error if the Meta Pixel API is not loaded.
-		 */
-		static loadGuard(): void {
-			if (!this._baseLoaded || !window.fbq) {
-				throw new Error('Meta Pixel API has not been loaded. Call PixelControl.load() first.');
-			}
-		}
-
-		private constructor(
-			trackingManager: MaybeGetter<TrackingManager | undefined>,
-			pixelID: string,
-			options?: PixelControlOptions
-		) {
-			this._trackingManager = trackingManager;
-			this._pixelID = pixelID;
-			this._testEventCode = options?.testEventCode;
-		}
-
-		/** Loads the Meta Pixel base script. */
-		static async load() {
-			if (this._baseLoaded && !!window.fbq) return;
-			if (!window.fbq) {
-				try {
-					await loadMetaPixel(); // Load the Meta Pixel script
-				} catch (e) {
-					log.warn('Failed to load Meta Pixel script, all events will be queued.', e);
-				}
-			}
-			this._baseLoaded = true;
-			log.debug('Meta Pixel base script loaded.');
-		}
-
-		/** Tells the Meta pixel that the user has given consent for tracking. */
-		static grantConsent() {
-			this.loadGuard();
-			window.fbq?.('consent', 'grant');
-			log.debug('Meta Pixel consent granted.');
-		}
-
-		/** Tells the Meta pixel that the user has revoked consent for tracking. */
-		static revokeConsent() {
-			this.loadGuard();
-			window.fbq?.('consent', 'revoke');
-			log.debug('Meta Pixel consent revoked.');
-		}
-
-		/**
-		 * Registers a PixelControl instance for the given Meta Pixel ID. If
-		 * the base Meta Pixel script has not been loaded yet, it will be
-		 * loaded automatically. Optionally sets a test event code for the Pixel.
-		 * Should only be called once for each Pixel ID, use PixelControl.get()
-		 * to retrieve existing instances.
-		 * @param trackingManager Tracking manager to handle user consent for tracking
-		 * @param pixelID Meta Pixel ID
-		 * @param options Optional settings
-		 * @returns PixelControl instance
-		 */
-		static initialize(
-			trackingManager: MaybeGetter<TrackingManager | undefined>,
-			pixelID: string,
-			options?: PixelControlOptions
-		): PixelControl {
-			// Load the base script if not already loaded
-			PixelControl.load();
-
-			// Check for existing PixelControl instance
-			if (this._registeredPixels[pixelID]) {
-				log.warn(
-					`PixelControl instance for Meta Pixel ID: ${pixelID} already exists. Returning existing instance.`
-				);
-				return this._registeredPixels[pixelID];
-			}
-
-			// Create and register the PixelControl instance
-			const pixel = new PixelControl(trackingManager, pixelID, options);
-			this._registeredPixels[pixelID] = pixel;
-
-			// Fire initialization
-			window.fbq('init', pixel._pixelID, options?.advancedMatching, options?.initOptions);
-			log.debug(`Meta Pixel [${pixel._pixelID}] initialized.`);
-
-			return pixel;
-		}
-
-		/**
-		 * Returns an existing PixelControl instance for the given Meta Pixel ID.
-		 * @param pixelID Meta Pixel ID
-		 * @returns PixelControl instance
-		 * @throws Error if no PixelControl instance is found for the given ID.
-		 */
-		static get(pixelID: string): PixelControl {
-			const pixel = this._registeredPixels[pixelID];
-			if (!pixel) {
-				throw new Error(`No PixelControl instance found for Meta Pixel ID: ${pixelID}`);
-			}
-			return pixel;
-		}
-
-		/**
-		 * Checks if the Meta Pixel has consent to track user data
-		 * and if the Pixel has been loaded.
-		 * @returns true if tracking is allowed, false otherwise.
-		 * @throws Error if the Meta Pixel is not loaded.
-		 */
-		consentGuard(): boolean {
-			PixelControl.loadGuard();
-			const trackingManager = resolveGetter(this._trackingManager);
-			return trackingManager?.haveUserConsent() ?? false;
-		}
-
-		/**
-		 * Sends a PageView event
-		 * @throws Error if the Meta Pixel is not initialized.
-		 */
-		pageView() {
-			if (!this.consentGuard()) return;
-			// Send the PageView event
-			if (!dev || this._testEventCode) {
-				window.fbq('track', 'PageView', undefined, { test_event_code: this._testEventCode });
-				log.debug(
-					`Meta Pixel [${this._pixelID}] PageView event sent${dev && ` (test code: ${this._testEventCode})`}.`
-				);
-			} else {
-				log.info(
-					`Meta Pixel [${this._pixelID}] PageView event not sent in development mode without a test event code.`
-				);
-			}
-		}
-
-		/**
-		 * Tracks a standard event for this pixel (uses `trackSingle` under the hood)
-		 * @throws Error if the Meta Pixel is not initialized.
-		 */
-		track<K extends StandardEventName>(event: K, params?: EventParamsByName[K], eventID?: string) {
-			if (!this.consentGuard()) return;
-			if (!dev || this._testEventCode) {
-				window.fbq('trackSingle', this._pixelID, event, params, {
-					eventID,
-					test_event_code: this._testEventCode
-				});
-				log.debug(
-					`Meta Pixel [${this._pixelID}] ${event} event sent${dev && ` (test code: ${this._testEventCode})`}.`
-				);
-			} else {
-				log.info(
-					`Meta Pixel [${this._pixelID}] ${event} event not sent in development mode without a test event code.`
-				);
-			}
-		}
-
-		/**
-		 * Tracks a custom event for this pixel (uses `trackSingleCustom` under the hood)
-		 * @throws Error if the Meta Pixel is not initialized.
-		 */
-		trackCustom(event: string, params?: CommonParams & CustomParams, eventID?: string) {
-			if (!this.consentGuard()) return;
-			if (!dev || this._testEventCode) {
-				window.fbq('trackSingleCustom', this._pixelID, event, params, {
-					eventID,
-					test_event_code: this._testEventCode
-				});
-				log.debug(
-					`Meta Pixel [${this._pixelID}] ${event} custom event sent (test code: ${this._testEventCode}).`
-				);
-			} else {
-				log.info(
-					`Meta Pixel [${this._pixelID}] ${event} custom event not sent in development mode without a test event code.`
-				);
-			}
-		}
-	}
-</script>
-
-<script lang="ts">
-	import { onMount } from 'svelte';
-
-	import type { TrackingManager } from './tracking.svelte.ts';
-	import type {
-		EventParamsByName,
-		StandardEventName,
-		CommonParams,
-		CustomParams,
-		AdvancedMatching,
-		InitOptions
-	} from './types/fbq.js';
-	import { loadMetaPixel } from './util/meta-pixel-loader.ts';
-	import { onNavigate } from '$app/navigation';
-	import { resolveGetter, type MaybeGetter } from './util/getter.ts';
-	import log from 'loglevel';
-	import { dev } from '$app/environment';
-
-	interface Props {
-		/**
-		 * Tracking manager to handle user consent for tracking. If omitted
-		 * tracking is disabled by default until consent is granted via
-		 * PixelControl.grantConsent().
-		 */
-		trackingManager?: TrackingManager;
-
-		/** Meta Pixel ID */
-		pixelID: string;
-
-		/** Meta Pixel Options */
-		pixelOptions?: PixelControlOptions;
-
-		/**
-		 * Controls whether page views are automatically tracked by this
-		 * component (default: true).
-		 */
-		autoPageView?: boolean;
-	}
-
-	let { pixelID, pixelOptions, autoPageView = true, trackingManager }: Props = $props();
-
-	let pixel = $state<PixelControl | null>(null);
-
-	onMount(() => {
-		if (!trackingManager) {
-			throw new Error('MetaPixel component requires a TrackingManager to manage consent.');
-		}
-		PixelControl.load();
-		pixel = PixelControl.initialize(trackingManager, pixelID, pixelOptions);
-
-		trackingManager.runWithConsent(() => {
-			if (autoPageView && pixel) {
-				pixel.pageView();
-			}
-		});
-	});
-
-	onNavigate(() => {
-		trackingManager?.runWithConsent(() => {
-			if (autoPageView && pixel) {
-				pixel.pageView();
-			}
-		});
-	});
-
-	export const getPixelControl = (): PixelControl => {
-		if (!pixel) {
-			throw new Error('MetaPixel component has not been initialized yet, wait for onMount.');
-		}
-		return pixel;
-	};
-</script>

src/lib/Umami.svelte

@@ -25,7 +25,9 @@
 	const consentGranted = $derived(trackingManager ? trackingManager.consent === true : true);
 
 	// Development overrides to prevent dirty analytics
-	const devConsoleTag = $derived(`[dev][consent: ${consentGranted ? 'granted' : 'revoked'}]`);
+	const devConsoleTag = $derived(
+		`[Umami] [dev][consent: ${consentGranted ? 'granted' : 'revoked'}]`
+	);
 	const devOverride = {
 		track: (...args: unknown[]): Promise<string> | undefined => {
 			log.debug(`${devConsoleTag}: Track called with:`, ...args);
@@ -62,7 +64,7 @@
 		}
 	});
 
-	if (dev) log.debug('[dev]: Umami tracking disabled');
+	if (dev) log.info('[Umami] [dev]: tracking disabled');
 
 	onMount(() => {
 		if (dev) {

src/lib/conversion/client.ts

@@ -1,6 +1,8 @@
+import { getFbpFbc } from '../metapixel/fbc.ts';
 import type { TrackingManager } from '$lib/tracking.svelte';
 import type {
 	ConversionErrorResponseBody,
+	ConversionEventParams,
 	ConversionRequestBody,
 	ConversionResponseBody,
 	ConversionUserData
@@ -37,17 +39,16 @@ export class ConversionClient {
 		options: {
 			eventID: string;
 			user?: Omit<ConversionUserData, 'ip' | 'fbp' | 'fbc' | 'ua'>;
-			customData?: Record<string, string>;
+			customData?: ConversionEventParams;
 		}
 	): Promise<ConversionResponseBody | ConversionErrorResponseBody> {
 		// Extract user data
-		const fbp = await cookieStore.get('_fbp');
+		const { fbp, fbc } = getFbpFbc();
-		const fbc = await cookieStore.get('_fbc');
 
 		const user: ConversionUserData = {
 			...options.user,
-			fbp: fbp?.value,
+			fbp,
-			fbc: fbc?.value
+			fbc
 		};
 
 		// Get event source URL & extract UTM params if present

src/lib/conversion/control.ts

@@ -1,12 +1,19 @@
 import {
+	Content,
 	CustomData,
 	EventRequest,
-	EventResponse,
 	ServerEvent,
 	UserData
 } from 'facebook-nodejs-business-sdk';
 import type { StandardEventName } from '../types/fbq.js';
-import type { ConversionUserData } from '$lib/types/conversion.js';
+import type {
+	ConversionEventDetails,
+	ConversionEventParams,
+	ConversionResponseBody,
+	ConversionUserData
+} from '$lib/types/conversion.js';
+import { dev } from '$app/environment';
+import log from 'loglevel';
 
 /**
  * Builds UserData for conversion events.
@@ -14,7 +21,7 @@ import type { ConversionUserData } from '$lib/types/conversion.js';
  * @param data - The user data to include.
  * @returns The constructed UserData object.
  */
-export const buildConversionUserData = (data: ConversionUserData): UserData => {
+const buildUserData = (data: ConversionUserData): UserData => {
 	const userData = new UserData();
 	if (data.email) userData.setEmail(data.email);
 	if (data.phone) userData.setPhone(data.phone);
@@ -34,40 +41,41 @@ export const buildConversionUserData = (data: ConversionUserData): UserData => {
  * @param params - The custom data parameters.
  * @returns The constructed CustomData object.
  */
-export const buildCustomData = (params: Record<string, string>): CustomData => {
+const buildCustomData = (params: ConversionEventParams): CustomData => {
 	const c = new CustomData();
-	// Map known fields safely
+	if (params.value) c.setValue(params.value);
+	if (params.net_revenue) c.setNetRevenue(params.net_revenue);
 	if (params.currency) c.setCurrency(params.currency);
-	if (typeof params.value === 'number') c.setValue(params.value);
+	if (params.content_name) c.setContentName(params.content_name);
-	if (Array.isArray(params.contents)) c.setContents(params.contents);
+	if (params.content_category) c.setContentCategory(params.content_category);
+	if (params.content_ids) c.setContentIds(params.content_ids);
+	if (params.contents) {
+		const contents: Content[] = params.contents.map((content) => {
+			const c = new Content();
+			if (content.id) c.setId(content.id.toString());
+			if (content.quantity) c.setQuantity(content.quantity);
+			if (content.item_price) c.setItemPrice(content.item_price);
+			if (content.title) c.setTitle(content.title);
+			if (content.description) c.setDescription(content.description);
+			if (content.category) c.setCategory(content.category);
+			if (content.brand) c.setBrand(content.brand);
+			if (content.delivery_category) c.setDeliveryCategory(content.delivery_category);
+			return c;
+		});
+		c.setContents(contents);
+	}
 	if (params.content_type) c.setContentType(params.content_type);
-	if (Array.isArray(params.content_ids)) c.setContentIds(params.content_ids);
+	if (params.order_id) c.setOrderId(params.order_id);
-	if (typeof params.num_items === 'number') c.setNumItems(params.num_items);
+	if (params.predicted_ltv) c.setPredictedLtv(params.predicted_ltv);
+	if (params.num_items) c.setNumItems(params.num_items);
 	if (params.search_string) c.setSearchString(params.search_string);
-	// Attach anything else as custom_properties
+	if (params.status) c.setStatus(params.status);
-	const extras = { ...params };
+	if (params.item_number) c.setItemNumber(params.item_number);
-	delete extras.currency;
+	if (params.delivery_category) c.setDeliveryCategory(params.delivery_category);
-	delete extras.value;
+	if (params.custom_properties) c.setCustomProperties(params.custom_properties);
-	delete extras.contents;
-	delete extras.content_type;
-	delete extras.content_ids;
-	delete extras.num_items;
-	delete extras.search_string;
-	if (Object.keys(extras).length) c.setCustomProperties(extras);
 	return c;
 };
 
-/**
- * Parameters for sending a conversion event to Meta Pixel.
- */
-export type ConversionEventOptions = {
-	eventID: string;
-	eventSourceURL?: string;
-	actionSource: 'website' | 'app' | 'offline' | 'other';
-	userData: UserData;
-	customData?: CustomData;
-};
-
 /**
  * Control class for sending Conversion API events to Meta Pixel.
  */
@@ -90,7 +98,8 @@ export class ConversionControl {
 	}
 
 	/**
-	 * Sends a conversion event to Meta Pixel.
+	 * Sends a conversion event to Meta Pixel. Requires a test event code for
+	 * events to be sent to Meta when in development mode.
 	 *
 	 * @param eventName - The name of the standard event to send.
 	 * @param options - Additional options for the event.
@@ -98,20 +107,51 @@ export class ConversionControl {
 	 */
 	async trackEvent(
 		eventName: StandardEventName,
-		options: ConversionEventOptions
+		details: ConversionEventDetails,
-	): Promise<EventResponse> {
+		params?: ConversionEventParams
+	): Promise<ConversionResponseBody> {
 		const event = new ServerEvent()
 			.setEventName(eventName)
 			.setEventTime(Math.floor(Date.now() / 1000))
-			.setEventId(options.eventID)
+			.setEventId(details.eventID)
-			.setUserData(options.userData)
+			.setUserData(buildUserData(details.userData))
-			.setActionSource(options.actionSource);
+			.setActionSource(details.actionSource);
 
-		if (options?.eventSourceURL) event.setEventSourceUrl(options.eventSourceURL);
+		if (details?.eventSourceURL) event.setEventSourceUrl(details.eventSourceURL);
-		if (options?.customData) event.setCustomData(options.customData);
+		if (params) {
+			const customData = buildCustomData(params);
+			event.setCustomData(customData);
+		}
+
+		// If we're in dev mode and missing a test event code, log and exit
+		if (dev && !this._testEventCode) {
+			log.debug(
+				`[ConversionControl] ${eventName} event not sent - missing test event code in dev mode.`
+			);
+			return Promise.resolve({
+				pixelID: this._pixelID,
+				fbtrace_id: 'dev-mode-no-test-event-code',
+				receivedEvents: 1,
+				processedEvents: 0,
+				messages: ['Event not sent - missing test event code in dev mode.']
+			});
+		}
 
 		const req = new EventRequest(this._accessToken, this._pixelID).setEvents([event]);
 		if (this._testEventCode) req.setTestEventCode(this._testEventCode);
-		return req.execute();
+		const response = await req.execute();
+
+		const structuredResponse: ConversionResponseBody = {
+			pixelID: response.id,
+			fbtrace_id: response.fbtrace_id,
+			receivedEvents: response.events_received,
+			processedEvents: response.num_processed_entries,
+			messages: response.messages
+		};
+
+		log.debug(
+			`[ConversionControl] Sent ${eventName}, Event response: ${JSON.stringify(structuredResponse)}`
+		);
+		return structuredResponse;
 	}
 }

src/lib/conversion/server.ts

@@ -1,13 +1,28 @@
 import { json, type RequestHandler } from '@sveltejs/kit';
-import { buildConversionUserData, buildCustomData, ConversionControl } from './control.ts';
+import { ConversionControl } from './control.ts';
 import type {
 	ConversionErrorResponseBody,
+	ConversionEventParams,
 	ConversionRequestBody,
-	ConversionResponseBody
+	ConversionUserData
 } from '$lib/types/conversion.js';
 
 import { StatusCodes } from 'http-status-codes';
 
+const getEventIP = (request: Request, getClientAddress: () => string) => {
+	return (
+		request.headers.get('x-forwarded-for') ||
+		request.headers.get('cf-connecting-ip') ||
+		request.headers.get('x-real-ip') ||
+		request.headers.get('x-client-ip') ||
+		request.headers.get('x-cluster-client-ip') ||
+		request.headers.get('x-original-forwarded-for') ||
+		request.headers.get('forwarded-for') ||
+		request.headers.get('forwarded') ||
+		getClientAddress()
+	);
+};
+
 export const createConversionRequestHandler: (control: ConversionControl) => RequestHandler = (
 	control
 ) => {
@@ -16,46 +31,38 @@ export const createConversionRequestHandler: (control: ConversionControl) => Req
 			const body = (await request.json()) as ConversionRequestBody;
 
 			// Build user data with IP and user agent
-			const ip = getClientAddress();
+			const ip = getEventIP(request, getClientAddress);
 			const ua = request.headers.get('user-agent');
 
-			const userData = buildConversionUserData({
+			const userData: ConversionUserData = {
 				...body.user,
 				ip,
 				ua: ua ?? body.user?.ua ?? undefined
-			});
+			};
 
 			// Build custom data with UTM params if applicable
-			let rawCustomData = body.customData ?? {};
+			let customData: ConversionEventParams = body.customData ?? {};
 			if (body.eventName === 'PageView' && body.utms) {
 				// For PageView events, automatically include UTM params if provided
-				rawCustomData = {
+				customData = {
-					...rawCustomData,
+					...customData,
 					...body.utms
 				};
 			}
 
-			const customData = buildCustomData(rawCustomData);
-
 			// Send the event via the control
-			const response = await control.trackEvent(body.eventName, {
+			const response = await control.trackEvent(
-				eventID: body.eventID,
+				body.eventName,
-				eventSourceURL: body.eventSourceURL,
+				{
-				actionSource: 'website',
+					eventID: body.eventID,
-				userData,
+					eventSourceURL: body.eventSourceURL,
+					actionSource: 'website',
+					userData
+				},
 				customData
-			});
+			);
 
-			// Structure the response
+			return json(response, { status: StatusCodes.OK });
-			const structuredResponse: ConversionResponseBody = {
-				pixelID: response.id,
-				fbtrace_id: response.fbtrace_id,
-				receivedEvents: response.events_received,
-				processedEvents: response.num_processed_entries,
-				messages: response.messages
-			};
-
-			return json(structuredResponse, { status: StatusCodes.OK });
 		} catch (e) {
 			return json(
 				{ error: e instanceof Error ? e.message : String(e) } as ConversionErrorResponseBody,

src/lib/index.ts

@@ -3,10 +3,12 @@
 import { dev } from '$app/environment';
 import log from 'loglevel';
 
+export type * from './types/conversion.d.ts';
 export type * as fbq from './types/fbq.d.ts';
-export { default as MetaPixel, PixelControl } from './MetaPixel.svelte';
+export * from './metapixel/index.ts';
 export * from './tracking.svelte.ts';
 export { default as Umami } from './Umami.svelte';
+export * from './conversion/index.ts';
 
 // set log level to debug if we're in dev mode
 if (dev) {

src/lib/metapixel/MetaPixel.svelte

@@ -0,0 +1,76 @@
+<!-- @component
+MetaPixel integrates the Meta (Facebook) Pixel into your Svelte application,
+allowing you to track page views and custom events while respecting user consent
+for tracking. The component manages the lifecycle of the Meta Pixel script and
+PixelControl interface.
+-->
+
+<script lang="ts">
+	import { onMount } from 'svelte';
+
+	import type { TrackingManager } from '../tracking.svelte.ts';
+	import { onNavigate } from '$app/navigation';
+	import { PixelControl, type PixelControlOptions } from './pixel-control.ts';
+	import { ensureFbc, type EnsureFbcOptions } from './fbc.ts';
+
+	interface Props {
+		/**
+		 * Tracking manager to handle user consent for tracking. If omitted
+		 * tracking is disabled by default until consent is granted via
+		 * PixelControl.grantConsent().
+		 */
+		trackingManager?: TrackingManager;
+
+		/** Meta Pixel ID */
+		pixelID: string;
+
+		/** Meta Pixel Options */
+		pixelOptions?: PixelControlOptions;
+
+		/**
+		 * Controls whether page views are automatically tracked by this
+		 * component (default: true).
+		 */
+		autoPageView?: boolean;
+	}
+
+	let { pixelID, pixelOptions, autoPageView = true, trackingManager }: Props = $props();
+
+	let pixel = $state<PixelControl | null>(null);
+
+	const ensureFbcOptions: EnsureFbcOptions = $derived({
+		sameSite: 'Lax',
+		pixelLoaded: PixelControl.baseLoaded && !PixelControl.baseFailed
+	});
+
+	onMount(() => {
+		if (!trackingManager) {
+			throw new Error('MetaPixel component requires a TrackingManager to manage consent.');
+		}
+		PixelControl.load();
+		pixel = PixelControl.initialize(trackingManager, pixelID, pixelOptions);
+
+		trackingManager.runWithConsent(() => {
+			if (autoPageView && pixel) {
+				pixel.pageView();
+				ensureFbc(ensureFbcOptions);
+			}
+		});
+	});
+
+	onNavigate(() => {
+		trackingManager?.runWithConsent(() => {
+			if (autoPageView && pixel) {
+				pixel.pageView();
+				ensureFbc(ensureFbcOptions);
+			}
+		});
+	});
+
+	export const getPixelControl = (): PixelControl => {
+		if (!pixel) {
+			throw new Error('MetaPixel component has not been initialized yet, wait for onMount.');
+		}
+		return pixel;
+	};
+</script>

src/lib/metapixel/fbc.ts

@@ -0,0 +1,88 @@
+import log from 'loglevel';
+
+export type EnsureFbcOptions = {
+	days?: number; // cookie lifetime, default 180
+	domain?: string; // optional cookie domain
+	sameSite?: 'Lax' | 'Strict' | 'None'; // default Lax
+	secure?: boolean; // default inferred from location.protocol === 'https:'
+	pixelLoaded?: boolean; // if true, skip manual set and let Pixel handle it
+};
+
+function getParam(name: string): string | undefined {
+	const params = new URLSearchParams(location.search);
+	const v = params.get(name);
+	return v || undefined;
+}
+
+function getCookie(name: string): string | undefined {
+	return document.cookie
+		.split('; ')
+		.find((c) => c.startsWith(name + '='))
+		?.split('=')[1];
+}
+
+function setCookie(
+	name: string,
+	value: string,
+	{
+		days = 180,
+		domain,
+		sameSite = 'Lax',
+		secure
+	}: Pick<EnsureFbcOptions, 'days' | 'domain' | 'sameSite' | 'secure'> = {}
+) {
+	const d = new Date();
+	d.setTime(d.getTime() + days * 864e5);
+	const parts = [
+		`${name}=${encodeURIComponent(value)}`,
+		`expires=${d.toUTCString()}`,
+		'path=/',
+		`SameSite=${sameSite}`
+	];
+	if (domain) parts.push(`domain=${domain}`);
+	const isSecure = secure ?? location.protocol === 'https:';
+	if (isSecure) parts.push('Secure');
+	document.cookie = parts.join('; ');
+}
+
+function isValidFbc(value: string | undefined): boolean {
+	if (!value) return false;
+	// Expect "fb.1.<unix>.<fbclid>"
+	if (!value.startsWith('fb.1.')) return false;
+	const parts = value.split('.');
+	return parts.length >= 4 && /^\d+$/.test(parts[2]) && parts[3].length > 0;
+}
+
+/**
+ * Ensure _fbc cookie exists when landing URL contains fbclid.
+ * Call after consent. If pixelLoaded is true, it skips manual setting.
+ */
+export function ensureFbc(options: EnsureFbcOptions = {}) {
+	try {
+		const { pixelLoaded = false, ...cookieOpts } = options;
+
+		if (pixelLoaded) throw new Error('Pixel loaded, skipping manual _fbc set'); // Let the Pixel set _fbc if it’s active
+
+		const fbclid = getParam('fbclid');
+		if (!fbclid) throw new Error('No fbclid param present');
+
+		const existing = getCookie('_fbc');
+		if (isValidFbc(existing)) throw new Error('_fbc cookie already present and valid');
+
+		const ts = Math.floor(Date.now() / 1000);
+		const fbc = `fb.1.${ts}.${fbclid}`;
+		setCookie('_fbc', fbc, cookieOpts);
+		log.debug('[ensureFbc] Set _fbc cookie:', fbc);
+	} catch (e) {
+		log.debug('[ensureFbc]', (e as Error).message);
+	}
+}
+
+/**
+ * Helper to read both _fbp and _fbc for your CAPI payload.
+ */
+export function getFbpFbc(): { fbp?: string; fbc?: string } {
+	const fbp = getCookie('_fbp');
+	const fbc = getCookie('_fbc');
+	return { fbp, fbc };
+}

src/lib/metapixel/index.ts

@@ -0,0 +1,4 @@
+export { default as MetaPixel } from './MetaPixel.svelte';
+export { PixelControl, type PixelControlOptions } from './pixel-control.ts';
+export * from './fbc.ts';
+export * from './pixel-control.ts';

src/lib/metapixel/pixel-control.ts

@@ -0,0 +1,320 @@
+import type { TrackingManager } from '../tracking.svelte.ts';
+import type {
+	EventParamsByName,
+	StandardEventName,
+	CommonParams,
+	CustomParams,
+	AdvancedMatching,
+	InitOptions
+} from '../types/fbq.js';
+import { loadMetaPixel } from '../util/meta-pixel-loader.ts';
+import { resolveGetter, type MaybeGetter } from '../util/getter.ts';
+import log from 'loglevel';
+import { dev } from '$app/environment';
+import { ConversionClient } from '../conversion/client.ts';
+import type { ConversionEventParams } from '$lib/types/conversion.js';
+
+const pixelParamsToCustomData = (params: CommonParams & CustomParams): ConversionEventParams => {
+	const customData: ConversionEventParams = {};
+	if (params.value) customData.value = params.value;
+	if (params.currency) customData.currency = params.currency;
+	if (params.content_name) customData.content_name = params.content_name;
+	if (params.content_category) customData.content_category = params.content_category;
+	if (params.content_ids) customData.content_ids = params.content_ids;
+	if (params.contents) {
+		const acc: ConversionEventParams['contents'] = [];
+		customData.contents = params.contents.reduce((acc, content) => {
+			acc.push({
+				id: content.id.toString(),
+				quantity: content.quantity
+			});
+			return acc;
+		}, acc);
+	}
+	if (params.num_items) customData.num_items = params.num_items;
+	if (params.search_string) customData.search_string = params.search_string;
+	if (params.predicted_ltv) customData.predicted_ltv = params.predicted_ltv;
+	return customData;
+};
+
+/**
+ * Options for configuring a PixelControl instance.
+ */
+export type PixelControlOptions = {
+	/**
+	 * if provided, events fired will always have this code attached
+	 * to prevent them from polluting real analytics data.
+	 */
+	testEventCode?: string;
+	/**
+	 * if provided, all events fired will be passed to the server endpoint
+	 * at this URL to be sent via the Conversion API. Any events sent
+	 * without a event ID will be assigned a random one.
+	 */
+	conversionHref?: string;
+	/** Advanced matching data */
+	advancedMatching?: AdvancedMatching;
+	/** Initialization options */
+	initOptions?: InitOptions;
+};
+
+/**
+ * Manages multiple Meta Pixel instances and provides methods to
+ * interact with them, including consent management and event tracking.
+ */
+export class PixelControl {
+	private _pixelID: string;
+	private _testEventCode?: string = undefined;
+	private _trackingManager: MaybeGetter<TrackingManager | undefined>;
+	private _conversionClient?: ConversionClient = undefined;
+
+	private static _baseLoaded: boolean = $state(false);
+	private static _baseFailed: boolean = $state(false);
+	private static _registeredPixels: Record<string, PixelControl> = {};
+
+	/** Indicates whether the Meta Pixel base script has been loaded. */
+	static get baseLoaded(): boolean {
+		return this._baseLoaded;
+	}
+
+	/** Indicates whether the Meta Pixel base script has failed to load. */
+	static get baseFailed(): boolean {
+		return this._baseFailed;
+	}
+
+	/**
+	 * Ensures that the Meta Pixel base has been loaded before
+	 * allowing further operations.
+	 * @throws Error if the Meta Pixel API is not loaded.
+	 */
+	static loadGuard(): void {
+		if (!this._baseLoaded || !window.fbq) {
+			throw new Error('Meta Pixel API has not been loaded. Call PixelControl.load() first.');
+		}
+	}
+
+	private constructor(
+		trackingManager: MaybeGetter<TrackingManager | undefined>,
+		pixelID: string,
+		options?: PixelControlOptions
+	) {
+		this._trackingManager = trackingManager;
+		this._pixelID = pixelID;
+		this._testEventCode = options?.testEventCode;
+
+		const resolvedTrackingManager = resolveGetter(trackingManager);
+		if (options?.conversionHref && resolvedTrackingManager) {
+			this._conversionClient = new ConversionClient(
+				options.conversionHref,
+				resolvedTrackingManager
+			);
+		} else if (options?.conversionHref) {
+			log.warn(
+				`[PixelControl] Conversion Client ${options.conversionHref} for Meta Pixel [${this._pixelID}] not initialized, TrackingManager is required for user consent.`
+			);
+		}
+	}
+
+	/** Loads the Meta Pixel base script. */
+	static async load() {
+		if (this._baseLoaded && !this.baseFailed && !!window.fbq) return;
+		if (!window.fbq) {
+			try {
+				await loadMetaPixel(); // Load the Meta Pixel script
+			} catch (e) {
+				log.warn('[PixelControl] Failed to load Meta Pixel script, all events will be queued.', e);
+				this._baseFailed = true;
+				return;
+			} finally {
+				this._baseLoaded = true;
+			}
+		}
+		log.debug('[PixelControl] Meta Pixel base script loaded.');
+	}
+
+	/** Tells the Meta pixel that the user has given consent for tracking. */
+	static grantConsent() {
+		this.loadGuard();
+		window.fbq?.('consent', 'grant');
+		log.debug('[PixelControl] Pixel consent granted.');
+	}
+
+	/** Tells the Meta pixel that the user has revoked consent for tracking. */
+	static revokeConsent() {
+		this.loadGuard();
+		window.fbq?.('consent', 'revoke');
+		log.debug('[PixelControl] Pixel consent revoked.');
+	}
+
+	/**
+	 * Registers a PixelControl instance for the given Meta Pixel ID. If
+	 * the base Meta Pixel script has not been loaded yet, it will be
+	 * loaded automatically. Optionally sets a test event code for the Pixel.
+	 * Should only be called once for each Pixel ID, use PixelControl.get()
+	 * to retrieve existing instances.
+	 * @param trackingManager Tracking manager to handle user consent for tracking
+	 * @param pixelID Meta Pixel ID
+	 * @param options Optional settings
+	 * @returns PixelControl instance
+	 */
+	static initialize(
+		trackingManager: MaybeGetter<TrackingManager | undefined>,
+		pixelID: string,
+		options?: PixelControlOptions
+	): PixelControl {
+		// Load the base script if not already loaded
+		PixelControl.load();
+
+		// Check for existing PixelControl instance
+		if (this._registeredPixels[pixelID]) {
+			log.warn(
+				`[PixelControl] Instance for Meta Pixel ID: ${pixelID} already exists. Returning existing instance.`
+			);
+			return this._registeredPixels[pixelID];
+		}
+
+		// Create and register the PixelControl instance
+		const pixel = new PixelControl(trackingManager, pixelID, options);
+		this._registeredPixels[pixelID] = pixel;
+
+		// Fire initialization
+		window.fbq('init', pixel._pixelID, options?.advancedMatching, options?.initOptions);
+		log.debug(`[PixelControl] [${pixel._pixelID}] initialized.`);
+
+		return pixel;
+	}
+
+	/**
+	 * Returns an existing PixelControl instance for the given Meta Pixel ID.
+	 * @param pixelID Meta Pixel ID
+	 * @returns PixelControl instance
+	 * @throws Error if no PixelControl instance is found for the given ID.
+	 */
+	static get(pixelID: string): PixelControl {
+		const pixel = this._registeredPixels[pixelID];
+		if (!pixel) {
+			throw new Error(`No PixelControl instance found for Meta Pixel ID: ${pixelID}`);
+		}
+		return pixel;
+	}
+
+	/**
+	 * Checks if the Meta Pixel has consent to track user data
+	 * and if the Pixel has been loaded.
+	 * @returns true if tracking is allowed, false otherwise.
+	 * @throws Error if the Meta Pixel is not loaded.
+	 */
+	consentGuard(): boolean {
+		PixelControl.loadGuard();
+		const trackingManager = resolveGetter(this._trackingManager);
+		return trackingManager?.haveUserConsent() ?? false;
+	}
+
+	/**
+	 * Sends a PageView event
+	 * @throws Error if the Meta Pixel is not initialized.
+	 */
+	pageView() {
+		if (!this.consentGuard()) return;
+
+		let eventID: string | undefined = undefined;
+		// Optionally, send to conversion API endpoint if configured
+		if (this._conversionClient) {
+			eventID = crypto.randomUUID();
+			this._conversionClient
+				.trackEvent('PageView', { eventID })
+				.then((response) => {
+					log.debug(
+						`[PixelControl] [${this._pixelID}] PageView event sent to Conversion API with Event ID: ${eventID}, Response: ${JSON.stringify(
+							response
+						)}`
+					);
+				})
+				.catch((error) => {
+					log.error(
+						`[PixelControl] [${this._pixelID}] Failed to send PageView event to Conversion API with Event ID: ${eventID}`,
+						error
+					);
+				});
+		}
+
+		// Send the PageView event to Meta
+		if (!dev || this._testEventCode) {
+			window.fbq('track', 'PageView', undefined, {
+				test_event_code: this._testEventCode,
+				eventID
+			});
+			log.debug(
+				`[PixelControl] [${this._pixelID}] PageView event sent${dev && ` (test code: ${this._testEventCode})`}.`
+			);
+		} else {
+			log.info(
+				`[PixelControl] [${this._pixelID}] PageView event not sent in development mode without a test event code.`
+			);
+		}
+	}
+
+	/**
+	 * Tracks a standard event for this pixel (uses `trackSingle` under the hood)
+	 * @throws Error if the Meta Pixel is not initialized.
+	 */
+	track<K extends StandardEventName>(event: K, params?: EventParamsByName[K], eventID?: string) {
+		if (!this.consentGuard()) return;
+
+		// Optionally, send to conversion API endpoint if configured
+		if (this._conversionClient) {
+			eventID = eventID ?? crypto.randomUUID();
+			this._conversionClient
+				.trackEvent(event, { eventID: eventID, customData: pixelParamsToCustomData(params ?? {}) })
+				.then((response) => {
+					log.debug(
+						`[PixelControl] [${this._pixelID}] ${event} event sent to Conversion API with Event ID: ${eventID}, Response: ${JSON.stringify(
+							response
+						)}`
+					);
+				})
+				.catch((error) => {
+					log.error(
+						`[PixelControl] [${this._pixelID}] Failed to send ${event} event to Conversion API with Event ID: ${eventID}`,
+						error
+					);
+				});
+		}
+
+		// Send the PageView event to Meta
+		if (!dev || this._testEventCode) {
+			window.fbq('trackSingle', this._pixelID, event, params, {
+				eventID,
+				test_event_code: this._testEventCode
+			});
+			log.debug(
+				`[PixelControl] [${this._pixelID}] ${event} event sent${dev && ` (test code: ${this._testEventCode})`}.`
+			);
+		} else {
+			log.info(
+				`[PixelControl] [${this._pixelID}] ${event} event not sent in development mode without a test event code.`
+			);
+		}
+	}
+
+	/**
+	 * Tracks a custom event for this pixel (uses `trackSingleCustom` under the hood)
+	 * @throws Error if the Meta Pixel is not initialized.
+	 */
+	trackCustom(event: string, params?: CommonParams & CustomParams, eventID?: string) {
+		if (!this.consentGuard()) return;
+		if (!dev || this._testEventCode) {
+			window.fbq('trackSingleCustom', this._pixelID, event, params, {
+				eventID,
+				test_event_code: this._testEventCode
+			});
+			log.debug(
+				`[PixelControl] [${this._pixelID}] ${event} custom event sent (test code: ${this._testEventCode}).`
+			);
+		} else {
+			log.info(
+				`[PixelControl] [${this._pixelID}] ${event} custom event not sent in development mode without a test event code.`
+			);
+		}
+	}
+}

src/lib/types/conversion.d.ts

@@ -16,6 +16,47 @@ export type ConversionUserData = {
 	externalId?: string;
 };
 
+/**
+ * Supported custom data fields for conversion events.
+ */
+export type ConversionEventParams = {
+	value?: number;
+	net_revenue?: number;
+	currency?: string;
+	content_name?: string;
+	content_category?: string;
+	content_ids?: string[];
+	contents?: {
+		id?: string;
+		quantity?: number;
+		item_price?: number;
+		title?: string;
+		description?: string;
+		category?: string;
+		brand?: string;
+		delivery_category?: string;
+	}[];
+	content_type?: string;
+	order_id?: string;
+	predicted_ltv?: number;
+	num_items?: number;
+	search_string?: string;
+	status?: string;
+	item_number?: string;
+	delivery_category?: string;
+	custom_properties?: Record<string, unknown>;
+};
+
+/**
+ * Parameters for sending a conversion event to Meta Pixel.
+ */
+export type ConversionEventDetails = {
+	eventID: string;
+	actionSource: 'website' | 'app' | 'offline' | 'other';
+	userData: ConversionUserData;
+	eventSourceURL?: string;
+};
+
 /**
  * Request body for conversion event tracking.
  */
@@ -28,7 +69,7 @@ export type ConversionRequestBody = {
 		Record<'utm_source' | 'utm_medium' | 'utm_campaign' | 'utm_content' | 'utm_term', string>
 	>;
 	user?: Omit<ConversionUserData, 'ip'>;
-	customData?: Record<string, string>;
+	customData?: ConversionEventParams;
 };
 
 /**

src/lib/types/fbq.d.ts

@@ -39,7 +39,7 @@ export type CommonParams = Partial<{
 	/**
 	 * Product IDs associated with the event, such as SKUs (e.g. ["ABC123", "XYZ456"]).
 	 */
-	content_ids: (string | number)[];
+	content_ids: string[];
 
 	/**
 	 * Name of the page/product.