Apollo.io
How it works: Sales intelligence + outreach in one place. Discover decision makers, get verified emails, and push multi-step sequences. Works with HubSpot, Salesforce, and most CRMs.
Why we rate it: Advanced filters make micro-targeting easy. In our outbound tests, well-segmented lists and tailored copy drove strong open and reply rates versus generic scraping.
Best for: SDR teams, B2B agencies, founders running structured outbound.
- Strengths: Large B2B database, targeting by firmographic and tech stack, built-in sequencing.
- Watch-outs: Deliverability still depends on domain health and warm-up. Costs rise at higher volumes.