To set up a Smartlead custom tracking domain, create a CNAME record (Smartlead's example host is emailtracking) pointing to open.sleadtrack.com, then open each sending mailbox in Smartlead, go to its General tab, tick "Use a custom tracking domain" and enter the full address, such as http://emailtracking.yourdomain.com. Click Verify CNAME and confirm the lookup shows open.sleadtrack.com as the canonical name. Then send one real campaign email to a mailbox you control, because Smartlead's test emails don't carry working tracked links.
The tracking domain is a mailbox setting. Whether a campaign inserts open pixels or tracked links at all is a separate campaign setting, and Smartlead locks that choice once sending starts. Get both right before launch.
Evidence and disclosure: We checked Smartlead's custom tracking domain guide, its open tracking article, its bulk mailbox update API reference and related help pages on October 16, 2026. We did not configure a tracking domain in a private Smartlead account; UI labels come from Smartlead's current documentation and published screenshots. OutboundXYZ has an affiliate relationship with Smartlead, which did not decide these steps.
Quick reference (Smartlead's guide): Type CNAME · Host emailtracking · Value open.sleadtrack.com · TTL Automatic. In Smartlead: Email Accounts → mailbox → General → Custom tracking domain. Success: Verify CNAME shows
open.sleadtrack.comunder "Canonical name". Smartlead says the record can take 30 minutes to 24 hours to appear.
The settings involved
| Setting | Where it lives | Scope | Change later? |
|---|---|---|---|
| Custom tracking domain | Email Accounts → mailbox → General | One mailbox | Yes. Effect on running campaigns isn't documented. |
| Open and click tracking | Campaign Settings → Delivery Optimization → Tracking Settings: Don't track email opens, Don't track link clicks (older screens: What shouldn't we track) | One campaign | No. Locks once sending begins. |
| Plain Text Mode (older screens: Optimise Email Delivery) | Campaign settings | One campaign | Draft only. Disables tracking and removes HTML links, including unsubscribe. |
| Warmup the Custom Domain Tracking Link | Email Accounts → mailbox → Warm Up | One mailbox | Yes. Optional. |
Smartlead's current open tracking article says opens and clicks are tracked by default unless you switch on the "Don't track" options. Its plain-text article covers the link removal.
Before you start
- DNS access at the provider that actually hosts each zone. If your nameservers point to Cloudflare, edit there, not at the registrar.
- Connected mailboxes. For Google Workspace, see our Smartlead Google Workspace OAuth guide.
- A decision on shared versus per-domain tracking (next section).
- A mailbox you control to act as the test lead. Never test tracking by clicking links in a real prospect's email.
Choose one shared tracking host or one per sending domain
Smartlead documents two models. Combined tracking puts the CNAME on one aged or well-reputed domain and uses that hostname on every mailbox in the account. Individual tracking gives each sending domain its own emailtracking CNAME, keeping tracking siloed; Smartlead suggests it for experiments, fresh setups or building authority across several domains.
| Combined (one host) | Individual (one host per sending domain) | |
|---|---|---|
| DNS work | One record | One record per sending domain |
| Link hostname recipients see | The same host on every mailbox's mail | Matches the sending domain |
| Agency offboarding (our judgment) | Old client emails keep pointing at your DNS | The client's DNS holds its own record |
Smartlead presents the combined model as handy for client work because it condenses tracking to one domain. Our view differs: for several clients, a tracking host on each client's own domain keeps a cleaner boundary, matches the sender in every link, and leaves nothing tied to your agency's DNS when a client leaves. Pair it with scoped Smartlead client access so each client sees only its own mailboxes.
Step 1: Add the CNAME record
- Open DNS management for the domain that will host tracking.
- Add Type: CNAME, Host: emailtracking, Value: open.sleadtrack.com, TTL: Automatic (or your provider's default).
- Enter the value as a bare hostname. Smartlead's panel displays it as a link, but a CNAME target never includes
https://. If your provider appends the domain automatically, type onlyemailtrackingas the host, or you'll getemailtracking.yourdomain.com.yourdomain.com. - Remove any other record at that exact name. A CNAME can't share a name with other data (RFC 1034, section 3.6.2).
- On Cloudflare, set the record to DNS only (grey cloud). Cloudflare's proxy status documentation says proxied CNAMEs are flattened and return Cloudflare's IPs, so a lookup won't show
open.sleadtrack.comas the canonical name, which is what Smartlead's check looks for. Smartlead's tracking-domain docs don't mention Cloudflare; this is our inference from both documents.
A label other than emailtracking should work, since Smartlead's settings text refers to "your tracking subdomain", but the hostname in DNS and in Smartlead must match exactly. If the domain also sends through another platform, give each platform its own subdomain: one hostname can only have one CNAME target.
Step 2: Add the domain to each Smartlead mailbox
- Go to Email Accounts and open the mailbox (or add a new one).
- Open the General tab and scroll to Custom tracking domain.
- Tick Use a custom tracking domain.
- Paste the full address as
http://{host}.{yourdomain}, for examplehttp://emailtracking.yourdomain.com, the format in Smartlead's guide. - Save, then repeat for every mailbox a tracked campaign will send from. Smartlead's low open rate troubleshooting page says to check each mailbox connected to the campaign, because the domain is set per mailbox, not per campaign.
The panel in Smartlead's screenshot says users with a custom tracking domain "see up to 20% improvement in deliverability". Smartlead doesn't publish how it measured that, so treat it as a vendor claim.
On HTTPS: the guide's example uses http://. Smartlead's bulk-update API reference says it strips http:// or https:// and verifies the CNAME and SSL, but no public page explains how a certificate is issued for your subdomain. Check the scheme in a real sent email (Step 3) rather than assuming.
Step 3: Verify DNS and the live links
DNS. Click Verify CNAME next to the field. Smartlead's guide says it opens an nslookup.io result that should list open.sleadtrack.com under "Canonical name". From a terminal, dig +short CNAME emailtracking.yourdomain.com should return the same. IP addresses instead usually mean a Cloudflare proxy; no answer usually means wait. Smartlead's DNS troubleshooting article allows 24 to 48 hours for DNS changes generally.
Live send. Smartlead says links don't work in test emails by design, so previews prove nothing here.
- Create a small campaign with your own mailbox as the only lead, tracking on, and one link in the copy.
- Send from a mailbox you just configured.
- In the received email, view the original or hover the link. The tracked link and open pixel should use
emailtracking.yourdomain.com, not a Smartlead hostname. - Note
http://orhttps://, then click from your own mailbox. It should redirect without a browser warning, and the click should appear in campaign analytics.
A Smartlead hostname in the link means that mailbox lacks the setting, or another mailbox sent the email. Report a certificate warning to Smartlead support; the docs don't cover it.
Changing domains later. Smartlead doesn't document whether running campaigns pick up a new domain. Emails already delivered keep their original hostname, so leave the old CNAME in place after a switch, or clicks in older emails break.
Bulk setup for agencies and large mailbox counts
Selecting mailboxes in Email Accounts and clicking Bulk Update opens a modal with General, Warm Up and Management tabs (plus SmartSender Profile for SmartSenders mailboxes). Smartlead documents the General tab for bulk signatures, but no help article says it includes the tracking-domain field. Check your own modal.
The documented bulk route is the API. The Bulk Update Email Account Config endpoint takes 1 to 1,000 email account IDs per request, processes them in batches of 100, and changes only the fields you send. customTrackingDomain sets the domain; useCustomDomain turns on tracking-link warmup.
POST https://server.smartlead.ai/api/v1/email-accounts/bulk-update-email-account-config?api_key=YOUR_API_KEY
{
"emailAccountIds": [101, 102, 103],
"updateData": {
"customTrackingDomain": "emailtracking.clientdomain.com",
"useCustomDomain": true
}
}
The IDs are placeholders. Smartlead verifies the CNAME and SSL on that call, so publish and verify DNS first. With individual tracking, send one request per sending domain so no mailbox gets another domain's hostname. The API key travels as a query parameter; keep it out of shared scripts, screenshots and tickets. A single-mailbox update endpoint also accepts custom_tracking_url.
Track the rollout in a sheet: mailbox, sending domain, tracking host, DNS verified, Smartlead field set, live send checked. Our cold email infrastructure stack covers the surrounding setup, and the email deliverability test checks a domain's public DNS signals.
Tracking-link warmup is optional. Smartlead's link warmup article says ticking Warmup the Custom Domain Tracking Link in a mailbox's Warm Up tab, then Update, adds your tracking links to warmup emails. The benefits are Smartlead's claim; we haven't measured them.
Should you track opens and clicks at all?
A tracking domain only matters for emails that carry tracking, and that choice locks at launch.
Smartlead's own article says open tracking relies on a pixel, that privacy features such as Apple Mail Privacy Protection can inflate or suppress opens, and that turning tracking off reduces pixels and redirect links, which may help some deliverability strategies. It suggests validating with its SmartDelivery tests. Our open rate calculator explains why open counts need privacy caveats.
In a December 2022 troubleshooting video, Jan listed a missing tracking domain next to SPF, DKIM and DMARC as basic setup to fix, and suggested removing links when open rates looked weak. That's dated operating advice, not a current test, and not a reason to treat today's open rates as precise.
Our editorial starting points, not measured results:
| Your situation | Starting point |
|---|---|
| Reply-led campaign, no links | Consider both "Don't track" options; judge by replies. |
| You need click data on one link | Keep click tracking, use a tracking domain, keep links minimal. |
| You report opens to clients | Keep opens on with a tracking domain; label opens as directional. |
Plain Text Mode removes Smartlead's built-in unsubscribe link, so read our Smartlead unsubscribe link guide before choosing it. With both tracking options off, still inspect a real send: Smartlead doesn't document which hostname any remaining Smartlead-generated link uses. Run copy through our email spam checker to catch unnecessary links and unresolved tokens.
Troubleshooting
| Symptom | Likely cause | What to check |
|---|---|---|
| Verify CNAME shows IPs, no canonical name | Record proxied in Cloudflare | Switch to DNS only and recheck. |
| Lookup finds nothing | Not propagated, or edited at the wrong DNS host | Confirm authoritative nameservers; wait up to 24 hours. |
| Canonical name points elsewhere | Another platform's CNAME on that host | Use a separate subdomain per platform. |
| Test email links don't work | Documented test-email behavior | Use a real send to your own mailbox. |
| Live email shows a Smartlead tracking host | Mailbox not configured, or another mailbox sent it | Check General on every mailbox in the campaign. |
| No opens or clicks recorded | Tracking off, or Plain Text Mode | Check campaign settings; they can't change after launch. |
| Bulk API update fails | DNS not ready at verification | Confirm the CNAME resolves, then retry those IDs. |
If some of your mailboxes send from Instantly instead, its record and settings differ; see our Instantly custom tracking domain guide. For the wider decision on whether Smartlead fits your sending setup, see our Smartlead review.
Disclosure: OutboundXYZ has an affiliate relationship with Smartlead. These steps come from Smartlead's public documentation checked October 16, 2026, not a private account test, and report no deliverability result.
Frequently asked questions
What CNAME does Smartlead use for a custom tracking domain?
Smartlead's guide uses host emailtracking and value open.sleadtrack.com. You then enter the full address, such as http://emailtracking.yourdomain.com, in each mailbox's Custom tracking domain field.
Do I need a separate tracking domain for every Smartlead mailbox?
No. The setting is per mailbox, but Smartlead documents both one shared host for all mailboxes and one host per sending domain. Mailboxes on the same domain can share that domain's host.
How do I know my Smartlead tracking domain is working?
Verify CNAME should show open.sleadtrack.com as the canonical name. Then send a real campaign email to your own mailbox and confirm the tracked link uses your hostname and redirects. Test emails won't show it.
Can I change open or click tracking after a Smartlead campaign starts?
No. Smartlead says tracking choices lock once sending begins, so set them in the draft. The mailbox tracking domain is a separate, editable setting.
Should the tracking CNAME be proxied in Cloudflare?
Use DNS only. Cloudflare says proxied CNAMEs return its own IPs, so the lookup wouldn't show open.sleadtrack.com, which Smartlead's check expects.
