What an IP address has to do with email

Every email is delivered by a server with an IP address. Inbox providers such as Gmail and Outlook keep track of the reputation of each sending IP address: how much it sends, how many messages bounce and how often recipients mark them as spam. A good reputation helps your email reach the inbox. A poor reputation sends it to spam or gets it rejected.

Shared IP or dedicated IP

A shared IP address is used by many senders at the same time. Your email is judged partly by what everyone else on that address sends, and you cannot control them. Shared IP addresses are often of poor quality.

A dedicated IP address is used only by you. Its reputation is built by your own sending, and other senders cannot damage it.

LeadJabber always recommends a dedicated IP address and never a shared IP. In SendGrid, the Pro plan is the first plan that includes a dedicated IP. See Create a SendGrid account for LeadJabber.

How many dedicated IP addresses you need

One. A single dedicated IP address is enough for outreach with LeadJabber, and more addresses do not improve delivery.

Why a new dedicated IP needs warm-up

A new IP address has no history, so inbox providers do not know whether to trust it. If a new address suddenly sends a large volume, it looks suspicious. Warm-up means that the volume from the new address increases gradually, so inbox providers can build trust in it. SendGrid and Mailgun both recommend warm-up for every new dedicated IP.

Why LeadJabber recommends automated IP warm-up

With automated IP warm-up, the gateway controls the warm-up for you. It limits how much the new IP address sends and raises the limit step by step over the first weeks. You do not need to plan volumes yourself or warm up mailboxes and domains, and you can start sending from day one. In SendGrid, automated warm-up ends on its own after the warm-up period.

To turn it on in SendGrid, go to Settings, then IP Addresses, open the action menu for your dedicated IP and select Use Automated IP warmup. See the section on warm-up in Create a SendGrid account for LeadJabber.

After a long break

SendGrid recommends warming up a dedicated IP again if it has not sent anything for more than 30 days. If you pause your outreach for longer than that, turn on automated IP warm-up again before you start sending.

What keeps the reputation good

A dedicated IP protects you from other senders, but its reputation still depends on what you send. Send to relevant recipients, keep bounces and spam complaints low, and honour every unsubscribe. See Manage your unsubscribe list and What are SPF, DKIM and DMARC?.