Moving a newsletter onto a new SendGrid IP can turn an ordinary campaign launch into a deliverability problem. The address has little sending history, and a large first send gives mailbox providers a lot to judge at once.

For SendGrid IP warmup, first confirm that you have a dedicated IP, use SendGrid's current warmup process for that IP and increase legitimate campaign traffic gradually. Add [MailSlurp email warmup](/product/email-warmup/) to prepare a verified SendGrid sender and inspect where the actual campaign lands. Those are related checks, with different results to watch.

## Confirm what you are warming

A domain identifies the sender; an IP is part of the infrastructure that delivers the message. A shared SendGrid pool and a dedicated IP need different planning. SendGrid manages its shared pools, while a newly assigned dedicated IP needs a gradual introduction.

Check the account that will send the campaign, including any subuser or IP-pool arrangement. Ask the administrator which IP or pool carries that message. A From address alone is not enough to identify its route. [SendGrid's dedicated-IP documentation](https://www.twilio.com/docs/sendgrid/ui/account-and-settings/dedicated-ip-addresses) is the reference for account configuration.

Our [IP versus domain warmup explanation](/blog/ip-warmup-vs-domain-warmup/) covers the distinction. For a new domain on an established pool, keep authentication, audience quality and a sensible introduction in the plan even though you are not warming a new dedicated IP.

## Use SendGrid's IP controls for the IP ramp

SendGrid documents automated warmup under **Settings > IP Addresses**. Open the dedicated IP's action menu, select **Use Automated IP warmup**, and save. Its automated process limits traffic through the warming IP by hour; other available IPs can carry traffic after that limit is reached. With no other available capacity, messages can be retried rather than immediately delivered.

Read the current [SendGrid IP warmup guide](https://www.twilio.com/docs/sendgrid/concepts/reputation/warm-up-ip-addresses) for its schedule and retry behavior. An hourly limit is capacity, not a recommendation to manufacture messages until you reach it. Your audience and campaign feedback still determine whether expanding is sensible.

Keep business-critical transactional traffic in view while changing routing. Before enabling a ramp, agree with the account administrator how delayed sends and other applications on that account will be handled.

## Connect the SendGrid sender in MailSlurp

MailSlurp has a SendGrid connection using its mail-send API. The [SendGrid connection guide](/docs/email-warmup/sendgrid/) lists the maintained setup requirements:

1. Authenticate the From address or sending domain in SendGrid.
2. Create a restricted API key with Mail Send permission.
3. In MailSlurp, open **Email warmup**, choose **Create warmup** and select SendGrid.
4. Enter the authorized sender and choose the US or EU region used by that account.
5. Verify the connection and complete its test delivery.
6. Review the goal, schedule, sending window and available placement coverage before starting.

Choose a pace that fits the sender's real workload. Include ordinary campaigns and application mail when considering total activity; the MailSlurp schedule accounts for its own program, not every send from every application.

If your SendGrid account uses special routing or several IP pools, inspect the [received test's headers](/tools/email-header-analyzer/) with the administrator to confirm its route. A successful API credential does not by itself prove that the new dedicated IP carried that message.



### Warm your SendGrid sender before the big send

Build sending activity gradually and watch what arrives. Connect your verified SendGrid sender to MailSlurp, then check warmup results alongside placement tests of the campaign you plan to send.

[Connect my SendGrid sender](https://app.mailslurp.com/sign-up/?onboardingRequest=warmup&returnTo=%2Femail-warmup%2Fcreate%2F%3FonboardingRequest%3Dwarmup)



## Read the three results separately

- **SendGrid accepted a send.** The provider accepted the request. Check delivery events, deferrals or rejection feedback.
- **MailSlurp warmup receipt or placement checkpoint.** This shows what happened to that program's observed messages. Check completed provider results and changes over time.
- **Placement test of the campaign.** This shows where that campaign copy landed at the tested seeds. Check provider differences, content and domain findings.

This separation is useful when a warmup program looks healthy but the new campaign reaches junk. The campaign may use different links, tracking, content or routing. Test that message before rewriting the whole warmup plan.

## Test the campaign that will go to subscribers

Create an [inbox placement test](/docs/inbox-placement/) in MailSlurp. Copy the current marker and seed addresses, place the marker in the campaign subject or body and send from the intended SendGrid route to the isolated seed audience.

Keep the sender identity, tracking and campaign content representative of the planned send. Verify that every seed was actually included, then wait for the observation window to finish. Review personal and business provider results separately; one good Gmail result does not explain a missing Microsoft result.

A completed seed test gives you a sample of campaign placement. Review it alongside SendGrid bounce, complaint and deferral feedback from legitimate subscribers. If the message also changed visually, run [device previews](/product/device-previews/) before expanding the send.

## Keep a recurring check on the sender

The same verified SendGrid connection can run an [automated inbox placement schedule](/docs/email-warmup/sendgrid/#schedule-automated-inbox-placement). Set its frequency, audience and message, retaining `{{trackingToken}}` in the subject or text body. Check an immediate **Run now** result and a later scheduled execution separately.

Use the scheduled message for comparable sender checks over time, and the campaign workflow above for the exact newsletter or application email you plan to send. Include all placement recipients and warmup messages when reviewing SendGrid's quota and trial expiry.

## When to hold the next increase

A connection error needs a connection repair. A volume or deferral problem needs a pacing and routing review. A spam result needs investigation of the delivered message and sender. Treating all three as "warmup failed" hides the useful next step.

Hold expansion when authentication is wrong, sends repeatedly fail, complaints rise or a provider's completed placement results worsen. Retest after the relevant repair with the same campaign configuration wherever possible. If several things changed together, avoid attributing an improvement to just one of them.

### Does warming a Gmail mailbox prepare my SendGrid IP?

That mailbox's messages use its own sending infrastructure. For SendGrid, use the SendGrid connection and verify which route carries the traffic you intend to prepare.

### Is completing the schedule a guarantee of inbox placement?

No schedule guarantees every recipient's inbox. Continue checking real campaign placement and production feedback after the ramp, especially after a sender, audience or template change.