Summary
Experts, marketers, and technical documentation consistently advise against using only BCC recipients in email communication due to its negative impact on deliverability. This practice is often flagged as a spam tactic by ISPs and spam filters, leading to damaged sender reputation, potential blacklisting, and reduced email engagement. A lack of a 'To' field, or failure to include recipient addresses in the 'To' or 'CC' fields, can also hinder delivery. Email authentication technologies are often absent when using mail clients directly for large mailings, adding to the problem. Dedicated email marketing platforms and personalized email strategies are recommended to avoid these issues and maintain good deliverability.
Key findings
- Spam Signal: Using only BCC recipients is a strong signal to ISPs and spam filters that the email may be spam.
- Damaged Reputation: This practice can significantly damage sender reputation, leading to future deliverability problems.
- Authentication Issues: Sending from standard email clients for bulk mailings often lacks proper email authentication.
- Delivery Failures: Some email systems require a 'To' or 'CC' field, potentially causing delivery failures with only BCC.
- Lack of Personalization: BCC-only sending prevents personalization and makes it harder to manage unsubscribes, impacting engagement.
Key considerations
- Use ESPs: Employ reputable email service providers (ESPs) for bulk email campaigns.
- Personalize Emails: Implement personalized email strategies to improve engagement and avoid spam filters.
- Authenticate: Ensure emails are properly authenticated using technologies like DKIM and SPF.
- Avoid BCC Alone: Avoid sending solely to BCC recipients; always include a valid recipient in the 'To' or 'CC' field.
- Manage Lists: Practice proper list management, ensuring you have permission to email recipients.
What email marketers say
10 marketer opinions
Using only BCC recipients in emails can negatively impact deliverability due to its association with spam tactics. Email marketers and experts across various platforms caution against this practice, citing potential damage to sender reputation, increased likelihood of emails being flagged as spam, and the lack of personalization and proper engagement tracking. Dedicated email marketing platforms are recommended for bulk sending to ensure better deliverability and adherence to best practices.
Key opinions
- Spam Association: ISPs often flag emails sent only to BCC recipients as spam because it's a common practice among spammers.
- Reputation Damage: Using BCC can damage your sender reputation, leading to lower deliverability rates.
- Lack of Personalization: BCC use lacks personalization, making it harder to manage unsubscribes and track engagement.
- Red Flag: Sending emails to only BCC recipients raises red flags for spam filters.
- Unprofessional Look: BCC'ing alone looks unprofessional and increases the risk of being marked as spam.
Key considerations
- Use ESPs: Consider using reputable email service providers (ESPs) for bulk email sending.
- List Management: Implement proper list management and segmentation practices.
- Authentication: Ensure you're using modern email authentication technologies like DKIM and SPF.
- Avoid BCC: Avoid using BCC-only sending; include a recipient in the 'To' field or use marketing software.
- Personalization: Personalize your emails to improve engagement and avoid spam filters.
Marketer view
Email marketer from Email Geeks questions the use case for large BCCs, suggesting it's a spammer trick that can impact deliverability.
30 May 2025 - Email Geeks
Marketer view
Email marketer from ActiveCampaign shares that relying solely on BCC can hurt deliverability. ISPs watch for patterns like this, and it makes it difficult to personalize messages or track engagement properly, making it easier for your emails to land in the spam folder.
31 Mar 2022 - ActiveCampaign
What the experts say
5 expert opinions
Experts across different platforms agree that using only BCC recipients can harm email deliverability. Having no 'To' field at all is detrimental, and even using 'undisclosed recipients' is not ideal. The practice can trigger spam filters because it's often used by spammers to hide recipients, potentially damaging sender reputation and preventing emails from reaching their intended targets. Experts recommend using a dedicated email marketing program for mailing lists that properly handles email authentication and individual emails.
Key opinions
- No 'To' Field is Bad: Having no 'To' field in an email is considered bad practice.
- Spammy Appearance: Not having the recipient's email address in the 'To' field looks suspicious and can resemble a DKIM replay attack.
- Delivery Prevention: Some configurations require the address to be in the 'To' or 'CC' field for delivery, which can prevent delivery if only BCC is used.
- Spam Filter Trigger: Using only BCC can raise red flags with spam filters due to its association with spam tactics.
- Authentication Issues: Using a mail client for list mailings likely means not using modern email authentication technologies.
Key considerations
- Use a 'To' Field: Always include a valid email address in the 'To' field.
- Consider Email Marketing Programs: For mailing lists, utilize a dedicated email marketing program that supports proper authentication.
- Avoid BCC-Only: Avoid using BCC as the sole recipient field due to potential deliverability issues.
- Check Mail Configurations: Be aware that some mail configurations might require addresses in the 'To' or 'CC' fields for successful delivery.
- Sender Reputation: Be aware of your sender reputation and avoid practices that can damage it.
Expert view
Expert from Email Geeks shares that not having the recipient's email address in the To: field looks spammy and like a DKIM replay attack, potentially leading to harsher treatment by consumer mailbox providers.
24 Sep 2024 - Email Geeks
Expert view
Expert from Spam Resource explains that when you only use the BCC field, it can raise red flags with spam filters because it's a common tactic used by spammers to hide recipients. This can negatively affect your sender reputation and lead to deliverability issues.
13 Feb 2024 - Spam Resource
What the documentation says
4 technical articles
Technical documentation from RFC Editor, Google, Microsoft, and SparkPost consistently discourages sending emails solely to BCC recipients. While the 'Bcc' field itself isn't inherently problematic, its misuse deviates from typical email patterns, triggering spam filters and potentially damaging sender reputation. It can signal to ISPs that the sender may not have permission to email the addresses, potentially indicating list buying or scraping. Google recommends using Google Groups or a dedicated email marketing service. Microsoft suggests using personalized emails and avoiding spam-like practices. Sending solely to BCC recipients can result in deliverability issues and blacklisting, as highlighted by SparkPost.
Key findings
- Deviates from Norm: Using only the BCC field deviates from typical email usage patterns, which anti-spam systems may penalize.
- Bulk Email Discouraged: Sending bulk emails only to BCC recipients is discouraged by major email providers like Google.
- Triggers Spam Filters: Practices like sending emails to a large list of BCC recipients can trigger spam filters.
- Reputation Damage: Sending solely to BCC recipients can damage sender reputation.
- Indicates List Issues: Sending only to BCC can signal to ISPs that you may not have permission to email those addresses, suggesting list buying or scraping.
Key considerations
- Use Appropriate Services: Consider using Google Groups or a dedicated email marketing service for bulk sending.
- Personalization: Use personalized emails to improve engagement and avoid spam filters.
- Avoid Spam Practices: Avoid practices that are common among spammers to maintain good deliverability.
- Follow Best Practices: Adhere to email sending best practices to avoid deliverability issues and blacklisting.
- Get Permission: Ensure you have permission to email the addresses on your list to avoid being flagged as a spammer.
Technical article
Documentation from SparkPost warns against sending solely to BCC recipients as it can damage your sender reputation. It is a signal to ISPs that you may not have permission to email those addresses, and could indicate list buying or scraping. This can lead to deliverability issues and blacklisting.
25 Feb 2023 - SparkPost
Technical article
Documentation from Microsoft explains that practices like sending emails to a large list of BCC recipients can trigger spam filters. Microsoft recommends using personalized emails and avoiding practices that are common among spammers to maintain good deliverability.
13 Jan 2023 - Microsoft
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