Your sender reputation plays an important role in determining whether your emails reach the inbox or are filtered as spam. One of the main decisions for high-volume senders is whether to send from a shared IP or a dedicated IP.

A shared IP is used by multiple senders, while a dedicated IP is reserved exclusively for your account. A dedicated IP gives you greater control over your sender reputation, but it also requires you to establish and maintain that reputation through responsible sending practices.

This guide explains when a dedicated IP may be suitable for your email program, how to request one from Mailjet, and how to warm it up gradually before sending your full email volume.

Why use a dedicated IP?

With a dedicated IP, your sender reputation is based entirely on your own sending activity. The practices of other senders cannot directly affect the reputation of your IP.

Your ability to reach the inbox therefore depends on factors such as:

• Your contact acquisition and consent practices.
• The quality and hygiene of your contact lists.
• The consistency of your sending frequency and volume.
• Recipient engagement with your emails.
• Your bounce, unsubscribe, and spam complaint rates.

A new dedicated IP has no sending history. Mailbox providers such as Gmail, Outlook, and Yahoo initially treat it as an unknown source. Gradually increasing your sending volume allows them to observe your sending behavior and build trust in your IP over time.

This process is known as IP warm-up.

Is a dedicated IP right for you?

We generally recommend a dedicated IP for customers sending more than 100,000 emails per month. To maintain a stable reputation, you should ideally send at least 3,000 emails per day.

A dedicated IP is most effective when your email volume is both high and consistent. If your sending volume is lower, irregular, or occasional, a shared IP may be a more efficient option because its sending reputation is supported by a continuous flow of email traffic.

How to get a dedicated IP with Mailjet

If you are subscribed to a Premium 100,000 plan or above and are interested in using a dedicated IP, contact our support team.

Our deliverability experts will review your sending profile and determine whether a dedicated IP is suitable for your email program. The assessment may include factors such as:

• Your expected monthly sending volume.
• Your sending frequency and volume consistency.
• Your contact acquisition and consent practices.
• Your current sender and domain reputation.
• Your engagement, bounce, and complaint history.

To learn more or request a dedicated IP, contact our support team.

How to warm up your dedicated IP

IP warm-up is the process of gradually increasing the number of emails sent from a new dedicated IP. Sending your full email volume immediately can cause mailbox providers to limit your traffic, reject your emails, or send them to the spam folder.

1. Check your domain quality

Before starting your IP warm-up, make sure your sending domain has a healthy reputation and is correctly configured.

• Check your domain reputation: Use tools such as Google Postmaster Tools to monitor your domain reputation. Avoid sending from a recently purchased or inactive domain whenever possible.
• Use an active domain: Your sending domain or subdomain should be associated with an active website. If you use a subdomain, consider redirecting it to your main website.
• Authenticate your emails: Configure SPF and DKIM to verify that Mailjet is authorized to send email on behalf of your domain. You should also consider implementing DMARC to protect your domain against unauthorized use.

2. Increase your sending volume gradually

Start with a small number of emails and gradually increase the volume as mailbox providers begin to recognize your IP as a legitimate sender.

3. Maintain a consistent sending schedule

Mailbox providers assess both your sending volume and your sending frequency. A predictable schedule helps them recognize your normal sending behavior.

• Send consistently: Send on regular days and avoid sudden changes in frequency or volume.
• Avoid long interruptions: Extended pauses can slow down the reputation-building process and may require you to resume at a lower volume.
• Increase only on sending days: If you send three times per week, increase the volume across those three sending days rather than assuming a daily schedule.

Sending every day may help establish a reputation more quickly, but a consistent schedule of several sends per week can also work. The most important factor is predictability.

4. Start with your most engaged contacts

Recipient engagement is an important signal used by mailbox providers when evaluating your reputation.

During the first stage of your warm-up, send only to recipients who have recently opened or clicked your emails. These contacts are more likely to interact positively with your messages and less likely to unsubscribe or report them as spam.

As your reputation develops, gradually include less recently engaged recipients while continuing to monitor your results.

You can use Mailjet's segmentation feature to identify and target contacts who actively engage with your emails.

5. Maintain good list hygiene

List quality is particularly important during IP warm-up. Invalid or unengaged contacts can generate negative signals that affect your reputation.

• Review bounces: Monitor hard and soft bounces after every sending and investigate unusual increases.
• Respect unsubscribes and complaints: Never send again to recipients who have unsubscribed or reported your messages as spam.
• Exclude inactive contacts: Avoid including recipients who have not engaged with your recent campaigns. Run re-engagement campaigns only after the warm-up process is complete.
• Remove invalid contacts: Correct obvious address errors and remove addresses that repeatedly fail.
• Use provable consent: Send only to contacts who have knowingly subscribed to receive your emails.

For detailed guidance, refer to our article on maintaining a list of responsive contacts.

6. Keep your sender identity and content consistent

Sudden changes to your sender identity or email content can make it more difficult for mailbox providers and recipients to recognize your messages.

• Use a recognizable sender: Keep your From name and sender address consistent throughout the warm-up process.
• Use familiar content: Send the type of content recipients expect based on how and why they subscribed.
• Avoid major template changes: Keep your branding, layout, and message structure relatively consistent while your reputation is being established.
• Avoid misleading content: Do not use deceptive subject lines, sender names, or calls to action.
• Include an unsubscribe link: Make it easy for recipients to stop receiving your marketing emails instead of reporting them as spam.

For additional recommendations, refer to our Mailjet Compliance and Email Deliverability Guide.

7. Monitor your performance and reputation

Review your campaign statistics after every sending. Do not increase your volume automatically without checking how the previous sending performed.

• Monitor your reputation: Use tools such as Google Postmaster Tools to review available reputation and delivery information.
• Track engagement: Monitor opens, clicks, unsubscribes, and spam complaints for changes in recipient behavior.
• Review bounces: Investigate increases in hard bounces, soft bounces, blocks, or throttling.
• Compare mailbox providers: Delivery performance may differ between Gmail, Outlook, Yahoo, and other providers.

How long does IP warm-up take?

A dedicated IP warm-up typically takes between two and six weeks. The exact duration depends on your target volume, sending frequency, recipient engagement, list quality, and deliverability performance.

The process may take longer when:

• You send only once or twice per week.
• Your target sending volume is particularly high.
• You pause your sending for an extended period.
• Your engagement decreases as you add less active recipients.
• Mailbox providers begin throttling or temporarily limiting your traffic.
• Your bounce or complaint rates increase.

Frequently asked questions