This is a large system that solves the problems of sales and marketing. We use it to maintain a base of potential customers. This CRM allows you to maintain a database of contacts, organizations, and transactions, receive customer requests through the site, track the history of their actions on the site, find out where they came from, and much more. HubSpot integrates with many services: Mailchimp, Slack, Facebook Ads, Zapier, Salesforce, and others.