Apollo.io

Apollo.io is a sales intelligence platform that gives you access to 265 million business contacts and 30 million companies. Unlike basic contact databases, Apollo combines prospecting with outreach automation, so you can find leads and email them from the same platform. The contact data is strongest for US tech companies, where you'll find direct emails for 70-80% of employees at most SaaS companies.

The email finder is Apollo's standout feature. Paste a company domain and get a list of employees with their likely email addresses. The verification system checks deliverability before you send, which protects your sender reputation. For common patterns like firstname@company.com, accuracy hits 85-90%. More creative email formats or smaller companies see lower success rates.

Sequence automation handles multi-step email campaigns with conditional logic. Set up a 7-email sequence, and Apollo will automatically skip steps if someone replies or mark contacts as unresponsive after the final email. A/B testing lets you compare subject lines or message approaches across segments. The system tracks opens, clicks, and replies to optimize future campaigns.

For developers, Apollo's API provides programmatic access to the contact database and sequence management. Rate limits are generous at 100-300 requests per minute on paid plans. This makes it suitable for building custom prospecting tools or integrating lead generation into existing sales workflows. Webhook support enables real-time notifications when prospects reply or engage.

The CRM functionality syncs bidirectionally with Salesforce and HubSpot. This means prospects discovered in Apollo automatically appear in your CRM, while deal information flows back to inform future prospecting. Intent data shows which companies are researching solutions like yours, though this feature requires the Professional plan or higher.

Pricing starts free with 60 monthly email credits and 120 phone number credits. The Basic plan ($59/month) includes 1,000 email credits and email sequences. Professional ($99/month) adds 5,000 credits, call recording, and intent data. For high-volume usage, credits can disappear quickly — a single prospecting campaign might burn through a month's allocation.

Data quality varies significantly by geography and industry. US technology companies have excellent coverage, while international contacts and traditional industries often lack recent information or verified emails. Company data like revenue estimates and employee counts should be validated before making important decisions.