Woodpecker is an email marketing platform that is designed specifically for outbound sales. It's automation and personalization features are geared towards building warm and direct relationships with potential and existing customers. Woodpecker is known for its deliverability and various integrations within different CRM systems, such as Salesforce and Hubspot.
On the other hand, Stackmails is an email marketing platform that is designed for e-commerce marketers. It provides pre-designed email templates that are tailored to drive conversion for online stores. It's features include tracking of ROI, abandoned cart emails, and an A/B testing tool.
In summary, the main difference between Woodpecker and Stackmails lies in their target audience and purpose. Woodpecker is designed for outbound sales while Stackmails is intended for e-commerce marketing.