Avoid Spam Filters

Article author
Sarah Malone

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Email Service Providers (ESPs) often have strict rules to protect users from unwanted or undesirable emails. To avoid these "spam blockers" you need to follow email best practices. If you do not, your emails may bounce and never reach your intended audience. This, in turn, puts your domain health at risk.

Read on to learn how to avoid spam filters and improve email deliverability when you send emails via a mailbox connected to Apollo.

Let's (Not) Bounce

Please note that the guidelines below are only best practices. They are not guaranteed to eliminate all bounces or instances of spam-blocked emails. Spam filtering is user-specific—if someone marks an email as spam, their email service provider's spam filtering will update itself to catch similar emails in the future. Two people can receive the same email and encounter different filtering behavior.

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Email Deliverability Best Practices

Feeling Overwhelmed and Not Sure Where to Start?

We feel you! Staying clear of spam filters can be pretty daunting. If you're short on time and want a quick summary, hop into our email deliverability checklist and follow the best practices to improve your email deliverability rates.

At a high level, there are 2 primary causes for email bounces and ESPs marking emails as spam:

  1. Domain reputation
  2. Email content and formatting

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Domain Reputation

For a better chance of avoiding spam filters, follow the steps below to configure your domain settings.

Set Up the SPF, DKIM, and DMARC for Your Sending Domains

Welcome-listing your domain improves your deliverability and ISP reputation. You should configure the following domain attributes to help raise your spam score.

  • Set Up SPF Records: An authorization method that specifies which email servers can send and receive emails on behalf of your organization.
  • Set Up DKIM Policies: An authentication method that uses cryptography to securely encrypt and decrypt emails sent to and from your organization. It also prevents in-transit altering of sent or received messages.
  • Set Up DMARC Policies: An authentication method that specifies how to handle emails that don't pass SPF and/or DKIM checks. DMARC also generates reports to prevent email spoofing.
Dive Into Workspace Admin Guides

Follow the Google guides below for further reading.
Publish an SPF record
Publish a DMARC policy
Authenticate Your Email With DKIM

For more general info on how to avoid getting spam blocked by Gmail, see the "Prevent mail to Gmail users from being blocked or sent to spam" article.

Master of Your Domain (Providers)

The information you need to configure SPF, DMARC, and DKIM is specifically related to your domain and is not related to Apollo. Apollo doesn't have email servers. All emails are sent directly from your email provider. Instructions to configure SPF, DMARC, and DKIM vary by domain provider. Contact your domain provider to obtain this information and receive any support you need.

When you have configured SPF, DMARC, and DKIM, consider implementing the following:

Set Up a New Domain

This domain should be different from your primary sending domain and you should only use it to send marketing emails. Additionally, this means you can create new mailboxes from this domain and add and replace them in Apollo for each user profile. For more information on how to connect mailboxes to Apollo, refer to the Link Your Mailbox to Apollo.io article.

Set Up a New Tracking Domain

A tracking domain is a secondary (or sub) domain name related to your original domain. It allows Apollo to redirect a tracking pixel added to emails to track opens, clicks, and unsubscribes.

Tracking pixels are often flagged as spam. Tracking domains redirect the attention of the email from your main domain and will help with deliverability.

Follow these instructions to set up a new tracking subdomain.

Tighten Up Tracking Domains

On occasion, you may find that a server flags your domain as spam. If this happens, you can spin up a new one with the tracking subdomain. Make sure you follow the same instructions to create a new tracking subdomain with a different name to reset your deliverability if needed.

Email Content and Formatting

  • Remove Links from the Body of Your Email: Spam filters look for links, especially in first-contact emails. Ensure you've removed links from your signature and in the body of your emails.

  • Remove Images from the Body of Your Email: Images or attachments, especially in automated or first-contact emails, can activate spam blockers and cause bounces. Remove these assets and stick to text. Save your images and attachments for step 3 or later in sequences once you've sent a few other emails. As with links, even images in your signature can cause issues.

  • Don't Apply Special Formatting to Your Text: Spam blockers scan for formatted text. Avoid using different colors, fonts, bolding, italicization, and underlining.

  • Keep Your Paragraphs Concise: Lengthy content can activate spam blockers or cause bounces. Keep your wording simple and to the point.

  • Avoid Words that Trigger Spam Filters: Spam filters are constantly evolving. As a result, there isn't a shortlist of words to avoid. Try to communicate in a professional, personable way. Avoid words and phrases that sound suspicious, urgent, or needy. As a best practice, ask yourself if the email you intend to send is one you would want to receive yourself. For further recommendations, refer to Avoid Spam Triggers in Your Email Content.

  • A/B Test Your Messaging: Always test your messaging to see what works best. You can A/B test in Apollo to try multiple versions of a message. If one version has a higher bounce rate, compare the differences to understand the cause.

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Additional Considerations

Still having issues with spam-blocked emails? Here are some additional steps you can take:

  • Connect Apollo to a SendGrid or Mailgun Account: SendGrid and Mailgun are mass emailing services that use their own email servers. They also replace the tracking URLs and direct them to their servers to resolve deliverability issues. If you already use SendGrid or Mailgun, you can integrate your account with Apollo. If you do so, you do not need to configure a tracking subdomain. SendGrid and Mailgun manage your tracking links on their end.
    For Old-Timers Only!

    Please note, Apollo only recommends integrating with your SendGrid or Mailgun account if you already actively use their platform for transactional or marketing emails related to your service or product. If you don't, consider using this Apollo partner to help you follow deliverability best practices.

    Click here for more info on the SendGrid integration or here for more on the Mailgun integration.
    There Can Only Be One (Tracking Link)

    If you've connected your Apollo account to SendGrid or Mailgun and your emails are flagged as spam, you may need to replace the tracking link within your SendGrid or Mailgun account. Both platforms provide a feature that functions like Apollo's tracking subdomain. For more info and support on deliverability with your SendGrid or Mailgun account, refer to this help article for SendGrid or this support article for Mailgun.

  • Include an Unsubscribe Link in Your Email Signature: Customize the text in an opt-out link from your email settings. Apollo then automatically adds the link with your signature on all of the emails you send via mailboxes connected to Apollo. Recipients are more likely to click an unsubscribe link instead of marking your emails as spam. When a recipient unsubscribes, it does not affect your overall sending reputation. If they mark you as spam, it does. For more info on how to configure your unsubscribe link, refer to this article.
  • Update Apollo Send Limits: Head to Settings, click You, and then click the Mailboxes tab. Click a mailbox and consider lowering the sending limits to 50 emails per day with a delay of 90s between each email. For more info, refer to the Email Sending Limits Overview article. Want to follow best practices but need to send more emails? You can link more mailboxes to send a higher volume of emails without putting your domain at risk. Send Limits
  • Only Send Messages to Contacts with Verified Emails: Use the email status filter and the date refreshed in Apollo filter when prospecting. You should only add contacts with valid, up-to-date emails into your sequences.
    Stop, in the Name of Accuracy!

    If a contact with a verified email spam blocks you, it doesn't mean the email address is inaccurate. It means the contact likely exists and your email was either automatically or manually marked as unfit or inappropriate for delivery.

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