Custom domain: Setup and Onboarding
Use your own domain name in email and SMS links to boost brand credibility
By default, links inside Apsis One emails and SMS use Apsis's own tracking domain — tr.aonetrk.com. With Custom domain, you can replace this with your own domain (for example, promotions.heartland.one) so that links appear under your brand in both email clients and browser address bars.
💡 Why it matters - Recipients increasingly judge email legitimacy by what they see in link previews. A link going to your own branded domain looks recognisable and trustworthy; a link going to a generic tracking domain can feel anonymous or even suspicious. Custom domain helps with brand consistency, click-through rates, and deliverability reputation.
In this article
What is Custom domain?
Custom domain is a feature that lets you use your own domain names for the tracking links inside emails and SMS sent from Apsis One. The domain is presented to your profiles in:
Email link previews (when hovering over a CTA in a desktop email client).
The browser address bar after a recipient clicks through.
SMS link previews on mobile devices.
Web versions and landing pages.
You can use different custom domains at the account level or per Section — useful when you have multiple brands or business divisions in the same account.
The look of the URL
Without Custom domain, a link in your email looks like this:
https://tr.aonetrk.com/c/owSY9SzA7IoD7
With Custom domain configured, the same link becomes much more legible and on-brand:
https://promotions.heartland.one/c/owSY9SzA7IoD7
The path after the domain (/c/owSY9SzA7IoD7) stays the same — that's the tracking identifier. Only the domain changes.
Setup options
Apsis One supports two configurations:
Option | How it works | When to use |
1. One domain for the whole account | A single domain (e.g. marketing.heartland.one) is applied account-wide. All emails and SMS from every Section use it. | Single-brand businesses, or anyone who wants the simplest possible setup. |
2. Different domains per Section | Each Section can have its own custom domain (e.g. europe.heartland.one). Sections without one fall back to the account-level domain, then to Apsis's default if none is set. | Multi-brand or multi-region accounts where each Section needs distinct branding. |
💡 Fallback behaviour - If a Section has no domain configured, it uses the account-level domain. If neither is configured, Apsis's default tracking domain (tr.aonetrk.com) is used. You can mix and match — set Custom domain on a few Sections, leave others on the default.
Ownership and responsibility
Custom domain involves shared responsibility between you and Apsis. Here's who handles what:
Component | Owned by you | Owned by Apsis |
The domain itself | ✓ You own and control the domain through your registrar (e.g. GoDaddy, Cloudflare, your hosting provider). | — |
DNS records | ✓ You add the CNAME records we provide to alias your domain to our infrastructure. | — |
SSL certificates | — | ✓ We create, configure, and renew the SSL certificates so your domain serves HTTPS without you needing to manage that. |
SSL validation | ✓ You add the validation CNAME records we provide so we can issue and renew certificates. | — |
Tracking infrastructure | — | ✓ We host and maintain the tracking servers that handle link clicks and redirects. |
The domain must not already be in use - When you request a custom domain, make sure the domain is not currently resolved to any existing website via DNS. The CNAME records you'll add must point exclusively to our infrastructure — they can't coexist with another active service on the same domain.
Before you start
You need Account Owner or Admin User rights to request a Custom domain.
Decide on the subdomain(s) you want to use (typically a dedicated subdomain like links.yourbrand.com or e.yourbrand.com rather than your main domain).
Have access to your DNS provider — you'll need to add CNAME records during onboarding.
Confirm whether you want the domain at the account level or per Section.
Check that the domain isn't currently serving any active website or email service.
The onboarding process
Custom domain isn't a self-serve setting — it requires coordination between your team and Apsis to set up the technical infrastructure correctly. The process has four stages:
Step 1: Submit a request from Account settings
Click your Profile Icon and go to Account settings.
Click Custom Domain in the left menu.
Click Request in the top right corner.
In the request form:
Enter the custom domain name(s) you want to use.
Describe how you want to use them.
For each domain, indicate if it should apply to the whole account or to specific Section(s).
Step 2: Agree on the details
Once your request is submitted, Apsis will reach out to discuss your use cases, answer questions, and confirm the technical details. This is the right time to clarify anything about Section assignment, domain naming conventions, or rollout timing.
Step 3: Integrate the infrastructure
When the setup is ready on our side, we'll send you the CNAME records to add to your DNS. Two types of CNAMEs are typically involved:
The main CNAME pointing your custom domain to our tracking servers.
A validation CNAME that allows our infrastructure to validate the SSL certificate for your domain.
✅ Tip — Coordinate with whoever manages your DNS - In larger organisations, DNS is often managed by IT or a separate vendor — not the marketing team. Loop them in early and share the CNAME records as soon as you receive them. DNS changes can sometimes take 24–48 hours to propagate, so don't leave this to the last minute.
Step 4: Confirmation and activation
Once your DNS is configured and the certificates are validated, Apsis will contact you to confirm everything is ready. With your approval, the Custom domain is activated — and from that point, all new emails and SMS will use your domain in their tracking links.
💡 Already-sent emails are unaffected - Activation only applies to new sends. Emails that were already sent before activation continue to use the previous (default or different) tracking domain in their links — those links don't change retroactively.
Troubleshooting
Issue | Likely cause | Fix |
Request form says the domain is already in use | The domain is currently resolved to an active website or service via DNS. | Choose a different subdomain that isn't serving anything (e.g. links.yourbrand.com instead of www.yourbrand.com), or remove the existing DNS configuration first. |
Custom Domain tab is missing from Account settings | You don't have Account Owner or Admin User rights. | Ask your Account Owner to make the request, or to grant you Admin rights. |
SSL certificate validation is failing | The validation CNAME hasn't been added or hasn't propagated yet. | Confirm with your DNS provider that the CNAME is in place. DNS propagation can take up to 48 hours — wait, then ask Apsis to retry validation. |
Activated, but old links still use the default domain | Those emails were sent before activation, so the link domain is permanent for that send. | Custom domain only applies to new sends after activation. Re-sending an email will use the new domain. |
Want to use a different domain after activation | Domain change is a configuration update, not a self-serve setting. | Submit a new request from Account settings → Custom Domain explaining the change. We'll coordinate the swap. |
What's next?
About Sections — If you're considering different domains per Section, start by understanding how Sections are structured.
Domains (for tracking) — A different setting in Account settings: the domains that the website tracking script monitors. Don't confuse these with Custom domain for email/SMS links.
Email tool — See how custom domains appear in your email sendings once activated.