What is a custom tracking domain and why is it important?

A custom tracking domain uses your own brand's subdomain (e.g., clicks.yourcompany.com ) for all links within your emails. This improves brand consistency and can enhance recipient trust, as they see your domain in the link instead of a generic ESP domain. It also plays a role in sender reputation, as ISPs see consistent branding.

Is it beneficial to use separate subdomains for different types of emails?

Yes, using separate subdomains for different email types (e.g., marketing.yourdomain.com and transactional.yourdomain.com ) is a best practice. This helps isolate the sender reputation of each stream, meaning if one stream encounters deliverability issues, it's less likely to affect the others. It's a key strategy for maintaining high inbox placement rates.

What are the risks of using a single global tracking link?

If a global tracking link gets blocklisted or develops a poor reputation due to issues with one email stream (e.g., high spam complaints from marketing emails), it could potentially impact the deliverability of all other email streams that use that same tracking link. This creates a single point of failure for your email program.

How do I decide between separate and global tracking links?

The choice often depends on your organization's scale, email volume, and risk tolerance. For complex email programs with distinct email types, separate tracking links are generally recommended for better reputation isolation. For simpler setups, a global link might be sufficient, provided you diligently monitor its reputation. Most importantly, your chosen setup should support your specific business goals and analytics needs.

Should I use separate or global tracking links for different email subdomains? - Sender reputation - Email deliverability - Knowledge base

When structuring your email program, a common question arises: Should I use separate tracking links for each email subdomain, or can a single global tracking link suffice? This decision isn't always straightforward, and I've observed varying approaches even among major brands. The core of the matter revolves around balancing ease of management with the crucial need to maintain a strong sender reputation and ensure email deliverability. Let's delve into the considerations that can help you make an informed choice for your email sending strategy.

The choice between separate and global tracking links has implications for how you monitor engagement, segment your audience, and protect your domain's sending reputation from potential issues. Email subdomains themselves are often used to segment different types of email traffic, like transactional emails versus marketing newsletters. This segmentation helps isolate the reputation of each email stream. For example, if your marketing emails encounter deliverability issues, using a distinct subdomain means your critical transactional messages are less likely to be affected. The same logic applies, to some extent, to tracking links.

My goal is always to maximize inbox placement and minimize risks, and understanding the nuances of tracking link configuration is a key part of that. Ultimately, the best approach depends on your specific infrastructure, sending volume, and tolerance for administrative overhead. Let's explore the arguments for both sides.

Advantages of dedicated tracking links

Utilizing separate email subdomains for different email streams, such as marketing, transactional, and notifications, is a widely accepted best practice. This segregation helps to isolate the sender reputation of each stream. If your promotional emails, sent from marketing.yourdomain.com, experience a dip in engagement or trigger spam complaints, the reputation of transactional.yourdomain.com remains largely unaffected. This principle extends to tracking links as well. When you use a distinct tracking link subdomain for each email sending subdomain, you reinforce this isolation.

The primary advantage of having separate tracking links (e.g., track.marketing.yourdomain.com and track.transactional.yourdomain.com) for different email subdomains lies in reputation management. If a tracking link associated with a particular email stream, like promotional emails, gets flagged due to malicious activity or high spam complaints, it's the reputation of that specific tracking subdomain that takes the hit. This helps prevent a single negative event from jeopardizing the deliverability of all your email campaigns, especially critical transactional messages.

This granular control over reputation is crucial. Many blocklists (or blacklists) operate at the subdomain level, meaning a listing of marketing.yourdomain.com won't necessarily impact yourdomain.com itself. By aligning your tracking links with this subdomain strategy, you ensure that potential issues are contained. This separation also provides cleaner, more segmented analytics, allowing you to easily attribute click and open data to specific email types or campaigns.

The benefits of separate tracking

Using separate tracking links aligns with the strategy of isolating email streams for better deliverability and can improve your ability to manage campaign-specific reputation.

Reputation isolation: A problem with one email stream's tracking link is less likely to affect others, preserving overall domain health.
Granular analytics: Easier to analyze performance metrics specific to each email type or campaign, without data commingling.
Risk mitigation: Reduces the risk of a single bad link impacting your primary domain's deliverability across all sends.

Simplicity and unified data with global tracking

Conversely, a global tracking link across all your email subdomains (e.g., track.yourdomain.com for all email types) offers simplicity. This approach significantly reduces the administrative burden of setting up and managing multiple tracking domains. For organizations with numerous subdomains or those just starting to segment their email traffic, a global link can be appealing due to its straightforward implementation and unified reporting.

However, this simplicity comes with a trade-off. If your global tracking link experiences deliverability issues – perhaps it gets associated with spam due to a compromised account or a particularly poor email campaign – it could potentially impact the deliverability of all your email streams. While major internet service providers (ISPs) and blocklists like Spamhaus are becoming more nuanced in their blocklisting (often targeting subdomains rather than parent domains), a compromised global tracking link can still cast a wide shadow over your entire email program. This risk is higher if your email volume is low, as it's harder to dilute negative signals across many sends.

The decision often hinges on your existing tracking system and business objectives. If your current reporting setup benefits from consolidated data, a global link might be more efficient. However, the potential for a single point of failure affecting all your email streams is a significant concern that needs to be carefully weighed against the convenience. It’s important to consider how your chosen email service provider (ESP) handles custom tracking domains, as some may require separate tracking domains per sending domain.

Separate tracking links

Reputation management: Provides strong isolation, limiting damage from issues on one subdomain.
Analytics clarity: Offers clean, segmented data for each email stream, improving analysis.
Deliverability impact: Less risk of one subdomain's tracking issues affecting other streams.
Administrative overhead: Requires more setup and ongoing management for multiple tracking domains.

Global tracking links

Reputation management: A single point of failure, potentially impacting all email streams.
Analytics clarity: Consolidated data, which may require more complex filtering for specific stream analysis.
Deliverability impact: Higher risk of a single issue affecting all sends from your primary domain.
Administrative overhead: Lower, as only one tracking domain needs to be set up and maintained.

Implementing tracking links and DNS

Regardless of whether you choose separate or global tracking links, the underlying technical setup primarily involves DNS records. Custom tracking domains (or subdomains) are typically configured using a CNAME record that points to your ESP's tracking domain. This allows the links in your emails to reflect your brand's domain rather than the ESP's, improving trust and brand consistency.

For separate tracking links, you'd create multiple CNAME records, each corresponding to a specific email subdomain. For example, clicks.marketing.yourdomain.com and clicks.transactional.yourdomain.com would each have their own CNAME. A global tracking link, on the other hand, would involve a single CNAME record, such as clicks.yourdomain.com, used across all email types. This is fundamental to whether tracking URL subdomain alignment affects email deliverability.

Example CNAME Record for a Global Tracking LinkDNS

clicks.yourdomain.com. CNAME esptracking.com.

It's also worth noting how email service providers (ESPs) handle these configurations. Many ESPs encourage or even require dedicated tracking domains for each sending domain or subdomain you authenticate within their platform. This is because their internal systems are often set up to manage reputation and deliverability based on these distinct configurations. While you can typically use a single tracking subdomain with a single ESP, if you're sending from multiple ESPs, you will likely need a custom tracking domain for each one. This ensures proper integration and data capture across your entire email ecosystem.

Views from the trenches

Best practices

Maintain distinct tracking domains for different email streams to isolate reputation risks and enhance deliverability.

Align your tracking link subdomains with your email sending subdomains for consistent branding and easier troubleshooting.

Regularly monitor the reputation of all your sending and tracking domains to catch potential issues early.

Common pitfalls

Using a single global tracking link for all email types can expose your entire email program to a single point of failure.

Neglecting to set up custom tracking domains and relying on generic ESP domains can negatively impact recipient trust.

Not consistently monitoring the health of all your email subdomains and their associated tracking links.

Expert tips

Consider the complexity of your email program and the resources available for managing multiple tracking domains.

Prioritize isolating critical email streams (like transactional emails) from higher-risk marketing sends.

Remember that the primary purpose of tracking links is data collection, so ensure your setup supports your reporting needs.

Expert view

Expert from Email Geeks says that the real deciding factor is what is the right way for your tracking system, as domain decisions should support business goals.

2022-03-30 - Email Geeks

Expert view

Expert from Email Geeks says that major email filters are sophisticated enough that one mistake will not break all your mail.

2022-03-30 - Email Geeks

Making the right choice for your strategy

The choice between separate or global tracking links for your email subdomains ultimately depends on your specific operational needs and risk management strategy. While a global tracking link offers administrative simplicity and consolidated data, it introduces a single point of failure that could impact all your email streams if issues arise. Conversely, separate tracking links, while requiring more setup and ongoing management, provide superior reputation isolation and more granular analytics, significantly reducing the risk of a widespread deliverability problem.

I generally lean towards separate tracking links when possible, especially for organizations with high sending volumes or distinct email categories (e.g., transactional versus marketing). This approach mirrors the benefits of using subdomains to segment email streams for overall deliverability improvement. If your ESP allows for flexible tracking domain configuration, leveraging this capability to align tracking links with their respective sending subdomains is a robust strategy.

Regardless of your choice, consistent monitoring of your domain and tracking link reputation is paramount. Keeping an eye on deliverability metrics and any unusual activity can help you quickly address issues and maintain healthy sender standing. The goal is always to deliver your messages effectively and reliably.