Sending a feedback mail after conducting an interview with a candidate will be considered as a good professional ethic. Keeping your candidates up-to-date with the interview process engages them and improves the overall hiring experience and candidate experience. Be it positive or negative feedback, sending a feedback mail after the interview should be a must if you want to enhance your employer brand.
Subject: Interview at [Company_Name] for [Job_Title]
We appreciate you taking the time to apply to [Company_Name]. We would like to inform you that we have finished conducting the interview and we have chosen to take a step forward with you for the [Job_Title] position since we feel that you are the most suitable candidate for this position.
We were impressed with your (e.g. performance on the assignment / in-person communication/experience in X tool), we are already excited to see you take full responsibility for the [job] goals.
It was a pleasure getting to know you and we would like to invite you for a meeting to discuss the intricacies of the position.
Thanks again for showing your interest in [Company name].
We look forward to your response.