Internal Email Service Development

I need a developer who can create a fully-functional internal email service for my company. The service should include standard features and functionalities that are essential for a corporate environment.

Key Requirements:
- Creation of a fully-functional internal email service
- Implementation of standard username and password for authentication
- Incorporation of crucial email service features such as spam filtering and email forwarding
- Web browser compatibility is a must

Ideal Skills:
- Proficiency in server-side programming languages
- Experience in developing email services
- Knowledge of spam filtering and email forwarding systems
- Web development expertise

Please note that the email service does not need to support mobile apps or desktop applications, but it should be fully compatible with web browsers.