SMTP Server Email Interface Development

I need a web-based interface that can efficiently send emails via all SMTP servers including Gmail, Outlook, and Yahoo Mail. The interface should also be able to support sending emails with attachments.

The ideal candidate for this project should have:
- Proficient experience in developing web-based email sending interfaces
- Strong understanding of SMTP servers and protocols
- Previous experience in handling attachments in email systems
- Ability to deliver a reliable and secure solution

Key deliverables:
- A user-friendly web interface for sending emails
- Support for multiple SMTP servers
- Ability to attach files to emails
- Secure and efficient email sending functionality