Why Client Cold Emails Should Not Use Public URL Shorteners
A short link looks tidy in a plain-text email. It also hides where the click goes, and it puts a domain your client does not control into every message they send. For cold outreach on a client's domain, that trade is rarely worth it.
This post covers what mailbox providers and blocklists say about links, why shared shortener domains are a risk, and a simple link rule to set per client.
Spam filters read the links, not just the sender
It is easy to think of reputation as a property of the sending domain. Filters also look at every domain that appears in the message.
Spamhaus says its Domain Blocklist (DBL) is meant to be checked "during content inspection – by looking up domains appearing in the mail headers and body e.g., URLs or contact email addresses." So if any domain in the body is listed, the message can be flagged or rejected even when the sender's own authentication is perfect.
Google's sender guidelines make a related point from the reader's side: "Web links in the message body should be visible and easy to understand. Recipients should know what to expect when they click a link." Google also tells senders to "regularly check the status of any domains that are linked to yours" with Safe Browsing.
The problem with public shorteners
A public shortener domain is shared by everyone who uses it, including people sending spam and phishing. Its reputation is the sum of all that traffic, and your client's message inherits it.
Spamhaus treats this as a known category. The DBL has a dedicated return code, 127.0.1.103, for "abused spammed redirector domain." Its guidance to shortener operators includes "Don't string several shorteners/redirectors together," because spammers chain redirects to get past domain checks. Public shorteners such as bit.ly have been listed in the DBL in the past (it was widely reported in 2011 and 2012); listings come and go, and you cannot control when the next one happens.
There is also the reader. A cold email arrives from someone the prospect has never heard of. A link that hides its destination asks for more trust than the email has earned.
What redirects count as
Shorteners are not the only redirect in a typical cold email. Click tracking rewrites every link through a tracking domain, and some tools then send that through another redirect. Each hop is another domain in the message and another reputation the client depends on. We have argued before for turning click tracking off on first touches; the same logic applies here.
A per-client link rule
Here is the rule we would set in every client workspace:
- No public shorteners in any step. Use the full destination URL.
- Link only to domains the client owns or clearly uses. Their website, their booking page, a case study on their site. If the prospect hovers, they should see the client's name.
- Keep the link count low on first touch. One link, or none. A first email exists to start a conversation, not to drive clicks.
- No chained redirects. If a link must pass through a tracker, it should be one hop, on a domain tied to the client and set up for that purpose.
- Check linked domains before launch and on a schedule. Look up every domain that appears in the sequence on the Spamhaus checker and Google's Safe Browsing status page. A client's old marketing domain or a third-party scheduling host can carry problems you did not create.
- Write links people can read. In plain text, show the URL itself rather than "click here." It answers the "where does this go" question before it is asked.
When a client insists on short links
Some clients like short links for tracking campaign sources. If the goal is attribution, a readable path on the client's own site does the same job (for example, a dedicated landing page per campaign) without adding a shared domain. If they still want a short domain, it should be one they own, used only for their mail, and checked like any other linked domain.
Where GTM fits
GTM writes from prospect evidence in each client's voice and runs a compliance gate before every send. Sending runs on each client's connected domains inside an isolated workspace, so one client's link choices do not leak into another's campaigns. A link rule is part of the client's brief: what may be linked, and where.
If you run outbound for several clients and want those rules enforced at the write step, join the waitlist.
Sources
- Spamhaus, "Domain Blocklist (DBL)": https://www.spamhaus.org/blocklists/domain-blocklist/
- Google, "Email sender guidelines": https://support.google.com/mail/answer/81126
- Spam Resource, "Spamhaus and URL Shortening Services" (2011): https://www.spamresource.com/2011/03/spamhaus-url-shortening-services_8.html
- Adweek, "Bit.ly, Goo.gl Blacklisted by Spamhaus": https://www.adweek.com/performance-marketing/bitly-googl-blacklisted-spamhaus-owly-listed-safe/