Skip to main content

Best practices for email deliverability

In this article, we will look at the aspects that influence email deliverability and provide you with a list of best practices to ensure the best deliverability for your campaigns.

Keep a clean contact database

Only import opt-in contacts

Sendinblue requires that you build your email lists with 100% opt-in contacts. Sending emails to opt-in contacts results in higher engagement and lower complaints, thus improving your deliverability.

Set up a double opt-in process

Using double opt-in confirmation creates an additional layer of protection to prevent:

  • Fake email addresses or contacts who aren’t really that interested in your emails from signing up
  • Bot flooding that could insert massively fake/wrong contacts to your contact list
  • Spam traps from the list you are building

Clean your contacts lists

Sendinblue automatically blacklists contacts who have unsubscribed from your emails, contacts who have marked your emails as spam, and contacts for whom an email has failed to be delivered and resulted in a hard bounce. No action is required on your side, and we advise you not to remove those contacts from your blacklist.

On your side, you should take the time to identify and remove contacts that are inactive or not engaged in your recent emails, as they can hurt your deliverability.

💡 Good to know
Before removing an inactive contact, you can try to provide them with content that might be more appealing by sending them a re-engagement email campaign.

Check your technical configuration

Choose between a shared IP and a dedicated IP

Choose between a dedicated IP or shared IP according to your sending volume.

  • Dedicated IP: a dedicated IP is used by a single email sender. If you plan on sending at least 3 campaigns a week with a minimum of 3000 emails, you may consider using a dedicated IP.
  • Shared IP: a shared IP is used by several email senders. If you plan on sending less than 3 campaigns a week with less than 3000 emails, you may consider using a shared IP.
💡 Good to know
You should not get a dedicated IP if you don't send at least 3 campaigns a week with a minimum of 3000 emails. If you do not send at least this volume of emails, your dedicated IP will never get any email reputation on the different webmails. In the better case, your dedicated IP is going to keep a forever neutral reputation – most usually, it will get a bad reputation. This means that your emails will very likely be delivered to the spam folder on many webmails. Webmails do not trust unknown IPs, and sending a very low or irregular volume of emails is seen as a bad behavior by webmails.

Associate your domain with your dedicated IP

Your dedicated IP needs to be associated with a sending domain for it to work correctly. Associating your domain with your dedicated IP also helps ensure that the domain listed as the sender on the email matches the domain that the email appears to have been sent from. When these values match, ISPs can more easily verify the identity of your sender and are much more likely to deliver your emails in your contacts' inbox.

Set up sender authentication

Use your domain name to digitally sign your emails with SPF, DKIM, and DMARC protocols.

  • SPF: DNS record that certifies that the sending IP is allowed to send emails from your domain.
  • DKIM: cryptographic protocol that allows you to sign your email with your domain name to ensure that the email is not altered during transmission and that the sender of the email is the owner of the sending domain.
  • DMARC: record that enforce a policy in case your domain is being spoofed by a bad guy by letting the webmail know what you want them to do with bad emails that try to spoof your brand.

Maintain a good sender reputation

Warm up your IP

This point is very important. If you use a dedicated IP, take the time to warm it up before sending large volumes of emails so that you build a positive reputation with ISPs and improve your deliverability.

❗️ Important
Most deliverability issues for users on dedicated IPs are due to a bad warm up. It takes weeks to build a reputation on a dedicated IP: if you send too many emails at once, your emails are going to be rejected by webmails and your dedicated IP may get blocked by them as well.

Check your sender score

Email sender score sits on a scale of 1-100 and reflects one of the many reputation elements of your IP, which is one factor that determines whether you are filtered out as a spammer. To get an assessment of your current sender score, go over to and plug in your IP address. If your score is not above 90, there is room for improvement.

Send your campaigns with the right timing and frequency

Sending your campaigns at the right time increases the likelihood that contacts will open and click on your emails. And remember, anything that improves engagement, improves deliverability as well. You can use Sendinblue’s Send Time Optimization feature to eliminate any guesswork by choosing the right time based on previous engagement data.

💡 Good to know
This feature is available for Premium and Enterprise plans. Compare plans here.

Target specific segments

Using list segmentation is a very good way to stick to good emailing practices, one of them being to only send emails to active contacts who have interacted with your emails (opens/clicks) in the last few months. Systematically sending emails to your full contacts database will lead to a lot of deliverability and reputation issues, as the oldest email addresses are often turned into spam traps by the webmails in order to catch spammers and bad senders.

Segmenting your contacts based on what you know about them is also useful to send more targeted email marketing campaigns. Segmenting will result in better campaign results and increased knowledge of your contacts.

Leverage automation

Marketing automation allows you to easily design customer journeys by building custom scenarios and sending campaigns based on your contacts' behavior.

Here are a few benefits you can get from using marketing automation:

  • Avoid mass emailing and increase your open and click rates by segmenting your contacts based on their behavior
  • Reward your contacts and increase their level of engagement to create a long-lasting relationship with your customers by sending them offers on special occasions

Build effective email campaigns

Create quality email content

Never compromise quality for quantity. If you slap together a poorly created email campaign, users are much more likely to complain.

Things to keep in mind when creating your email campaigns:

  • Make your emails mobile optimized
  • Avoid spam words in your emails
  • Test all of your links before sending and don't use URL shorteners such as or as they are considered fraudulent by anti-spam engines
  • Don’t use a bait and switch subject line
  • Personalize your campaigns with contact attributes
  • Include a clear call-to-action

Use the right FROM email address

Avoid using business and generic email addresses. Instead, send your emails from an email address that contains your name. For your marketing emails, you can even consider creating a persona such as "Brandon from Whateverthebrand" with its own email address.

Send your emails from a personalized email domain in order to help improve your email deliverability. Make sure that the domain used is your Reply-to email address is the same as the one used in the sender field, otherwise your email will be considered as a fraud attempt.

Comply with opt-out legislation

You do not want to keep contacts in your list if they aren’t interested in your content, as it will hurt your engagement. Make it easy for them to unsubscribe if they’ve lost interest. Otherwise, they might get frustrated and just send you to spam. And by making it easy, we mean having a clearly visible unsubscribe link in your email footer.

💡 Good to know
Having an unsubscribe link in your email campaign is mandatory. If you delete the unsubscribe link from your email campaign, Sendinblue will automatically add it back during the sending of your campaign.

Test your email campaigns

Sendinblue offers several options to test your email campaigns before sending them to all your contacts:

Monitor your metrics

Monitoring your metrics will help you judge the performance of an email campaign and decide which aspects should be improved.

Here are the key email marketing metrics that you should be tracking in order to evaluate your email campaigns:

  • Open rate: percentage of recipients who have opened an email divided by the number of emails delivered.
  • Click rate: percentage of recipients who have clicked an email divided by the number of emails delivered.
  • Bounce rate: percentage of failed deliveries in relation to the total number of recipients. There are two types of bounce rate: hard and soft.
  • Complaint rate: number of people who received your email and hit the “Report Spam” button divided by the number of emails delivered.
  • Unsubscribe rate: percentage of recipients who have unsubscribed from a campaign or emailing list via the unsubscription link. As long as it is below 1%, you should not be too concerned by it.

🤔 Have a question?

If you have a question, feel free to contact our support team by creating a ticket from your account. If you don't have an account yet, you can contact us here.