Email Link Best Practices: Tracking Links, Redirects, and URL Reputation

Why Links Matter More Than Content

Spam filters analyze your links more closely than your copy. A perfectly written email with one bad link will go to spam. The domain reputation of every URL in your email contributes to your overall message scoring.

The URL Shortener Problem

Shared URL shorteners — bit.ly, tinyurl.com, t.co (in email context), ow.ly — are a deliverability killer. Here's why:

• Spammers use them to hide malicious destinations
• Spam filters can't easily evaluate the final destination
• The shortener domain's reputation reflects all users, including bad actors
• Gmail, Outlook, and corporate filters flag them aggressively

The rule is simple: never use shared URL shorteners in email. Your ESP's tracking links serve the same purpose with your own domain reputation.

Practitioner note: A SaaS client switched from bit.ly links to their custom tracking domain and saw spam placement at Gmail drop from 22% to under 3%. The only change was the links. Everything else — copy, template, sending pattern — stayed identical.

Link Density Guidelines

Email Type	Recommended Links	Maximum
Cold outreach	1	2
Transactional	2-3	5
Marketing newsletter	3-5	8-10
Product announcement	2-4	6

Every additional link increases the surface area for spam filter analysis. Each link domain gets checked against blacklists, reputation databases, and known-spam patterns.

Redirect Chains Kill Deliverability

When a recipient clicks a link in your email, the path might look like:

tracking.youresp.com → yourdomain.com/redirect → finaldestination.com

Each redirect adds latency and filter scrutiny. Keep redirect chains to 2 hops maximum (tracking domain → final destination). Three or more redirects trigger spam heuristics at most major providers.

Link Reputation Checking

Before every campaign, verify that none of your linked domains are blacklisted:

• Google Safe Browsing: transparencyreport.google.com/safe-browsing
• SURBL: surbl.org
• URIBL: uribl.com
• Spamhaus DBL: spamhaus.org/dbl

If any domain in your email (including the tracking domain) appears on these lists, your email is going to spam.

Anchor Text vs Raw URLs

Use descriptive anchor text instead of raw URLs:

<!-- Good -->
<a href="https://example.com/pricing">See pricing details</a>

<!-- Bad -->
<a href="https://example.com/pricing">https://example.com/pricing</a>

<!-- Worst — mismatched -->
<a href="https://example.com/tracking">https://example.com/pricing</a>

Mismatched anchor text (where the visible URL doesn't match the href) is a phishing indicator. Spam filters flag it immediately. If you show a URL, make sure it matches where the link actually goes.

Practitioner note: I see the mismatched anchor text problem most often with agencies using GoHighLevel or HubSpot sequences. The tracking link rewrite makes the href different from the display URL. Custom tracking domains fix this because the display URL and href share the same root domain.

Unsubscribe Links

Your unsubscribe link is a legal requirement (CAN-SPAM, GDPR) and a deliverability signal. Place it where recipients can find it — burying it in 6pt grey text doesn't reduce unsubscribes, it increases spam complaints.

See our unsubscribe link design guide for placement and implementation details.

The Link Checklist

Before every campaign:

1. All links resolve (no 404s)
2. No shared URL shorteners
3. Custom tracking domain configured
4. Maximum 2 redirect hops
5. No blacklisted domains (check SURBL, URIBL, Spamhaus DBL)
6. Anchor text matches destination context
7. Unsubscribe link visible and functional

If your links are clean and your emails still hit spam, the problem is likely authentication or reputation. Get a deliverability audit to find out exactly what's going wrong.

Sources

• Spamhaus: Domain Block List
• SURBL: URI Reputation Data
• Google: Safe Browsing Transparency Report
• RFC 5321: SMTP Protocol

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v1.0 · April 2026