&quot;Tradition in such plain text messages is to surround the URL with &lt; and &gt; as kind of quotation marks (as the latter can be problematic too; depends on the algorithm of the URL detector): You can see that in &lt;<a href="http:&#x2F;&#x2F;example.com&#x2F;foo&gt;.&quot;" rel="nofollow">http:&#x2F;&#x2F;example.com&#x2F;foo&gt;.&quot;</a>