Email Warmup Tools for Gmail and Outlook (2026): Pricing and How Each Connects

If you are choosing an email warmup tool for Gmail and Outlook mailboxes, the provider list on a vendor's homepage tells you very little: almost every tool lists both. The useful questions are how the tool connects each kind of mailbox, which admin settings on the Google or Microsoft side can block it, and how the price behaves as you add mailboxes. This page compares the tools buyers ask about most on exactly those points. Everything about a competitor was read from its own pricing page or help center in October 2026.

This is about choosing a tool. For the warmup schedule itself, the DNS records and the reputation dashboards, see the separate Gmail and Outlook guides linked at the end.

Three ways a warmup tool connects Gmail and Outlook

• Sign in with Google or Microsoft (OAuth). You click a button, approve access, and no password is stored. For Gmail this needs Google's restricted mail scope, which a vendor must pass a paid security assessment to use, so not every tool offers it. A Google Workspace or Microsoft 365 admin may also have to approve the app first.
• App password. A 16-character password Google generates for one app. It needs 2-Step Verification on the account, and Google does not offer it when 2-Step Verification uses security keys only, on Advanced Protection accounts, or when a Workspace admin has not allowed it.
• IMAP and SMTP. Server settings plus a password, for any host that allows it: Zoho, Yahoo, iCloud, custom domains. Microsoft 365 often has authenticated SMTP switched off per user, so this route usually needs an admin to turn it on.

Email warmup tools for Gmail and Outlook: pricing comparison 2026

Gmail and Google Workspace: what to check per tool

Google sign-in is the smoothest route when it works, but on Google Workspace it often needs the admin first. Instantly's own guide has a Workspace admin open Security, Access and data control, API controls, and mark Instantly's OAuth client as Trusted by pasting its Client ID. lemlist says an "Access blocked" error means the admin has restricted third-party apps. If you are an agency connecting client mailboxes, that admin step is the part that waits on someone else.

Tools that use app passwords skip the admin console but depend on each user. 2-Step Verification has to be on, the user has to paste the app password rather than their normal one, and a Workspace admin can still have app passwords or IMAP turned off. MailReach documents app passwords for single Gmail and Workspace mailboxes, and domain-wide delegation through a Google Cloud service account for connecting a whole Workspace domain at once.

Outlook and Microsoft 365: what to check per tool

Most tools connect Microsoft mailboxes with Microsoft sign-in, and the usual blocker is tenant policy, not the tool. Smartlead tells you to have an admin enable Authenticated SMTP and IMAP for each user in the Microsoft 365 admin center, then wait 20 to 30 minutes before connecting. MailReach's sign-in fails until a Global Administrator allows user consent in Microsoft Entra, or grants admin consent to the app. lemlist warns that multi-factor or conditional access policies can block the connection and leave it pending.

Personal Outlook.com and Hotmail accounts are a different Microsoft sign-in from work and school accounts. If a tool asks which kind you have, pick carefully: the wrong one signs you into the wrong mailbox or fails outright.

How Warmerly connects Gmail and Outlook today

Warmerly connects Gmail and Google Workspace mailboxes with a Google app password. The app password route works on both personal Gmail and Workspace, and the setup screen walks through turning on 2-Step Verification and creating the password. If Google refuses it, Warmerly tells you the likely cause, such as 2-Step Verification being off or a Workspace admin having switched app passwords or IMAP off.

Microsoft 365, Outlook.com and Hotmail mailboxes connect with Microsoft sign-in, with separate options for work and personal accounts, and a password route as a fallback. Any other host with IMAP and SMTP connects by address and password, with the server settings filled in when Warmerly recognizes the provider. Proton Mail, which has no IMAP, and forwarding-only domains cannot connect.

Which tool to pick for Gmail and Outlook mailboxes

• One or two mailboxes, warmup only, lowest price: Warmup Inbox, or the free plans at TrulyInbox and Warmerly.
• Many mailboxes across Gmail and Microsoft 365, warmup only: TrulyInbox, if the shared daily volume is enough per mailbox.
• Whole Google Workspace domains connected by an admin in one go: MailReach, with domain-wide delegation.
• Already sending with lemlist: Lemwarm.
• Warmup plus a campaign sender, with Google sign-in: Instantly or Smartlead.
• Warmup plus unmetered campaign sending on Gmail and Outlook, priced by plan rather than per mailbox: Warmerly.