Deliverability

Tracking Domain Checker

Checks a click-tracking subdomain end to end: the CNAME to SparkPost, the HTTPS certificate and whether a test click really redirects.

Runs on our server
2 units per run

Open the tool

You enter: The tracking subdomain, for example track.example.com.
You get: CNAME target, HTTPS setup type, certificate, a live click test and the redirect chain.
A good result: A CNAME to v2.spgo.io (or eu.v2.spgo.io), a valid certificate and a test click that answers with a redirect.

On this page

What it is for
What you enter
How it works
Reading the results
Example
Limits and gotchas

#What it is for

Links in campaigns go through the tracking domain. If it is misconfigured, clicks fail or show a certificate warning. Use this tool after setting up a tracking domain and whenever recipients report broken links.

#What you enter

Only the tracking subdomain, such as track.example.com (not the main domain). A link with ?domain= runs the check straight away.

#How it works

Reads the CNAME and sorts its target: v2.spgo.io or eu.v2.spgo.io is SparkPost managed HTTPS, *.et.e.sparkpost.com is enterprise managed, plain spgo.io is the legacy setup.
Checks the certificate on the domain (and whether it is from Let's Encrypt, as SparkPost managed certificates are).
Sends a test click to https://<domain>/f/a/b/c/d and follows up to 5 redirects. Any 301, 302, 303, 307 or 308 counts as working.
Reads the server headers to tell SparkPost's edge, a CDN or proxy (Cloudflare, CloudFront, Fastly, Akamai) and a plain web server apart, and checks HSTS on the domain and on the root domain.

#Reading the results

The verdict is "Tracking is set up correctly" or "Issues found with tracking setup". The HTTPS setup type explains why:

SparkPost managed HTTPS: The recommended setup. Pass when the click test works.
Self-managed HTTPS proxy: A CDN or proxy you run in front of SparkPost. Fine when the click test passes; the CNAME shows as "Proxied" and that is expected.
Managed HTTPS pending or broken: The CNAME is right but HTTPS does not work yet. New certificates can take a while; if it persists, the setup in SparkPost needs attention.
Legacy SparkPost HTTPS: An older target. Works in some cases, but plan a move to v2.spgo.io.
HTTPS not working: No valid certificate or no redirect. Links will break for recipients.

Each type has a confidence (high, medium, low): low means the signals disagree and a manual click test is worth doing.

#Example

A correct DNS record

track.example.com  CNAME  eu.v2.spgo.io

With that record the tool should report SparkPost managed HTTPS, a Let's Encrypt certificate and a redirect from the test click.

#Limits and gotchas

The root domain is taken as the last two labels, so HSTS inheritance is misread for domains like example.co.uk.
Each probe waits at most 3 seconds; a slow proxy can make a working setup look broken. Repeat before changing DNS.
If the check fails on a track. domain, the tool offers to check the main domain in the DNS Checker.