I'm planning to use subdomains like marketing.codeninja.com or a separate domain like codeninja-marketing.com for email marketing in HubSpot. I want to ensure that this setup doesn't negatively impact the reputation or credibility of my main domain (codeninja.com). Could you guide me on the best practices for a subdomain or separate domain setup, including DNS authentication (SPF, DKIM, DMARC), and how to maintain email deliverability and trust while protecting my main brand?
You could set up email sending domains by clicking Settings -> Tools -> Content -> Domains & URLs and set it up from there. Here is an article with detailed info.
For email deliverability, there are online tools that offers detailed report (email deliverability tester). And if you want get an extra boost, you could try some email warm-up services.
In my experience, even subdomains can hurt the main domain in regards to e-mail. So if you plan to send many cold emails, it might be better to use another domain and gradually build up that domains authority before sending out many cold e-mails.
@KZakiI want to reiterate @Boosty's comment. You're playing with fire sending cold email from a subdomain. If your send volume is reasonably high you risk negatively impacting your domain reputation.
You could set up email sending domains by clicking Settings -> Tools -> Content -> Domains & URLs and set it up from there. Here is an article with detailed info.
For email deliverability, there are online tools that offers detailed report (email deliverability tester). And if you want get an extra boost, you could try some email warm-up services.