Apollo.io is a sales intelligence and engagement platform that combines a massive B2B contact database with outreach automation. With 275+ million contacts and 70+ million companies, it's one of the largest verified B2B databases available — used for prospecting, lead enrichment, and building targeted outreach lists. The sequencing tools automate multi-touch outreach across email, phone, and LinkedIn. AI features write personalized email drafts based on prospect data, suggest optimal send times, and score leads by likelihood to convert. CRM integration keeps data synchronized with Salesforce and HubSpot. For sales teams that need both data and outreach infrastructure in one platform — rather than stitching together separate enrichment, sequencing, and CRM tools — Apollo offers a comprehensive solution at competitive pricing.