If you’re using different tools for data collection (Google Analytics, Google Dynamic Remarketing, Facebook Pixel, etc.), it would be easier to manage all of them in Google Tag Manager interface. It allows you to keep all of your tags in one place, add them by yourself without any trouble, test changes before publishing, and be more independent from your developers.
I’ll help you to migrate your tags to Google Tag Manager without damaging the accuracy of your data. With this tool, future updates will be much easier to implement — and you will save your time and money.