Facebook Pixel is an analytics tool that allows you to measure the effectiveness of your advertising by understanding the actions people take on your website.
Google Analytics is a free Web analytics service that provides statistics and basic analytical tools for search engine optimization (SEO) and marketing purposes.
MailChimp is a web-based email marketing service. It helps you design email newsletters, share them on social networks, integrate with services you already use, and track your results.
Zapier is an online automation tool that connects your favorite apps, such as Gmail, Slack, MailChimp, and over 1,000 more. Use this to save doing repetitive tasks.