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Working with multiple trackers

GA

ga('create', 'UA-XXXXX-Y', 'auto');
ga('create', 'UA-XXXXX-Z', 'auto', 'clientTracker');

ga('send', 'pageview');
ga('clientTracker.send', 'pageview');

https://developers.google.com/analytics/devguides/collection/analyticsjs/creating-trackers#working_with_multiple_trackers

FB Pixel

fbq('init', '{{facebookPxelId1}}');
fbq('init', '{{facebookPxelId2}}');
fbq('track', "PageView");

https://stackoverflow.com/questions/34649311/will-it-cause-any-issue-if-i-use-multiple-facebook-pixel-in-one-page/43716681#43716681