E-commerce Payment Gateway Integration

I'm looking for an experienced web programmer to help integrate an external payment system into my e-commerce website.

Key Requirements:
- on payment, website send URL (long string) to third-party system and after that system will send a URL back for confirmation
- Integrate a third-party payment gateway.
- Redirect users to a confirmation page post successful transaction.
- Ensure a confirmation email is sent out after each transaction.
- Update our internal database with transaction details.

Ideal Skills:
- Proficiency in web programming.
- Prior experience with e-commerce payment integration.
- Familiarity with server-side programming for database updates.
- Understanding of client-side scripting for redirection and confirmation email setup.