Summary
Using a different domain for CDN-hosted images in emails can affect deliverability, with domain reputation being the most crucial factor. While some experts suggest the image domain might not inherently impact deliverability if the sending domain has a good reputation, the consensus, supported by various experts, marketers, and documentation, emphasizes that the reputation of the image hosting domain is vital. A poor reputation or blacklisting of the CDN domain can negatively impact deliverability, regardless of the sender's domain reputation. CDNs offer indirect benefits by improving website speed, security, and brand protection. Mapping the CDN to a subdomain and optimizing images can also enhance deliverability.
Key findings
- Domain Reputation is Paramount: The reputation of the image hosting domain significantly influences email deliverability. A negative reputation can cause deliverability issues, even with a clean sending domain.
- CDN Reputation Matters: It's important to ensure that the CDN being used has a good reputation. If the CDN domain is blacklisted, it will negatively impact deliverability.
- Indirect Benefits of CDNs: Using a CDN provides indirect deliverability benefits by improving website speed, security, and brand protection.
- Separate Domain is Standard: Utilizing a separate domain for CDNs is a common and recommended practice.
Key considerations
- Monitor CDN Reputation Regularly: Continuously monitor the CDN domain's reputation to prevent potential deliverability issues.
- Consider Subdomain Configuration: Configure the CDN to use a subdomain of your primary domain (e.g., cdn.example.com) for enhanced brand alignment and trust.
- Optimize Images: Optimize images for faster loading times, which indirectly contributes to better engagement metrics and improved deliverability.
- Use Reputable CDNs: Avoid using domains for CDN hosted images that you do not control and always use reputable CDNs.
What email marketers say
12 marketer opinions
Using a different domain for CDN-hosted images in emails can affect deliverability, primarily based on the reputation of the image hosting domain. While CDNs improve website speed and security, indirectly benefiting deliverability, a poor reputation or blacklisting of the CDN domain can negatively impact it, regardless of the sender's domain reputation. Configuring the CDN with a subdomain and optimizing images can also improve deliverability.
Key opinions
- Domain Reputation Matters: The reputation of the domain hosting images significantly impacts email deliverability. A poor reputation can lead to deliverability issues, even if the sending domain is clean.
- CDN Indirectly Benefits: Using a CDN improves website speed and adds security, which indirectly benefits email deliverability through improved user experience and brand protection.
- Blacklisting Hurts: If the CDN domain is blacklisted, it will negatively impact deliverability, regardless of the reputation of the sending domain.
- Direct Impact Not Always Clear: Using a CDN is not always a direct factor in deliverability. Other factors like sender reputation, authentication, and content are also important.
Key considerations
- Monitor CDN Reputation: Regularly check the reputation of the CDN domain to ensure it is not blacklisted or associated with spam.
- Configure Subdomain: Consider configuring the CDN to use a subdomain of your main domain (e.g., cdn.example.com) to align with your brand and improve trust.
- Optimize Images: Optimize images for faster loading times, as this contributes to better engagement metrics and deliverability.
- Controlled Domains: Avoid using domains for CDN hosted images that you do not control.
Marketer view
Email marketer from Reddit mentions that using a CDN with a clean reputation is important. If the CDN domain is blacklisted, it will negatively impact deliverability, regardless of whether it's your sending domain.
6 Oct 2023 - Reddit
Marketer view
Email marketer from Email Geeks explains that image domain can have some reputation associated with it, and spam delivery can result from a bad reputation image domain. But there shouldn't be impact from simply using images hosted at a different domain, as long as that different domain does not have reputation problems.
17 Nov 2021 - Email Geeks
What the experts say
6 expert opinions
The impact of using a different domain for CDN-hosted images on email deliverability is debated, but the consensus leans toward domain reputation being a crucial factor. While some experts believe the image domain shouldn't inherently impact deliverability if the company domain has a good reputation, others emphasize that the reputation of the image hosting domain is essential. Ensuring the CDN's domain is not blacklisted and maintaining a good reputation for all linked domains, including those hosting images, is crucial for avoiding deliverability issues.
Key opinions
- Domain Reputation: The reputation of the domain hosting the images plays a significant role in email deliverability.
- Company Domain Reputation: A good company domain reputation can mitigate some concerns about using a different CDN domain, but the CDN's reputation still matters.
- CDN Domain Blacklisting: Ensuring the CDN's domain is not blacklisted is critical to prevent negative impacts on deliverability.
- Image Hosting Reputation: The overall perception of the sender is influenced by all domains linked in an email including the image hosting domain.
Key considerations
- Monitor CDN Reputation: Regularly check and monitor the reputation of the CDN domain to ensure it is not associated with spam or blacklisted.
- Domain Alignment: Consider mapping the CDN to a subdomain of your primary domain for better domain alignment and potential trust benefits.
- Alternative Hosting: Assess whether hosting images directly within your marketing cloud instance is a viable alternative to avoid potential CDN-related deliverability issues, especially if CDN reputation is a concern.
- Reputable CDN: Ensure that you only use reputable CDNs
Expert view
Expert from Email Geeks explains that uploading 9k images to Marketing cloud shouldn’t be necessary if you are using a CDN serving all those same images to your website, one would hope the reputation is pretty solid.
28 Oct 2021 - Email Geeks
Expert view
Expert from Email Geeks explains that the image domain shouldn’t have any impact on email deliverability.
11 Mar 2024 - Email Geeks
What the documentation says
4 technical articles
Using a separate domain for CDN-hosted images is a common practice and doesn't inherently harm email deliverability, according to multiple documentation sources. The key factor is maintaining a good reputation for the CDN domain, as domain reputation is crucial across all domains linked in email campaigns, including image hosting. CDNs also enhance security, indirectly improving deliverability by protecting brand reputation.
Key findings
- Separate Domain is Common: Using a separate domain for CDNs is a standard and recommended practice.
- Reputation is Key: Maintaining a good domain reputation for the CDN is crucial for avoiding spam filters and ensuring deliverability.
- CDNs Enhance Security: CDNs improve security, indirectly boosting deliverability by protecting brand reputation.
Key considerations
- Monitor CDN Reputation: Continuously monitor the CDN domain's reputation to prevent deliverability issues.
- Domain Reputation Strategy: Integrate CDN domain reputation into your overall email deliverability strategy.
- Security Measures: Leverage CDN security features to safeguard brand reputation and indirectly improve deliverability.
Technical article
Documentation from Microsoft highlights the importance of maintaining a good domain reputation. This applies to all domains associated with your email campaigns, including those hosting images.
25 Aug 2021 - Microsoft
Technical article
Documentation from SendGrid explains that domain reputation is key. Whether it's your sending domain or the domain hosting your images, a positive reputation is crucial for avoiding spam filters.
21 Sep 2021 - SendGrid
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