How to Connect Google Workspace Mailboxes to Instantly and Smartlead

Instantly and Smartlead both send through your own mailboxes rather than their own servers, so every mailbox has to be connected. Which method you use depends on whether you control the Google Workspace admin console and how many mailboxes you have. Menu names below follow the vendors' help centres at the time of writing; vendors change their interfaces, so check the linked help articles if a label differs.

OAuth vs. IMAP/SMTP: which to use

Connect Google Workspace to Instantly with OAuth

1. 1

   Copy Instantly's Client ID

   In Instantly, go to Email Accounts → Add New (Add or Buy Accounts) → Connect existing accounts → Google → the OAuth option, and copy the Client ID shown there.

2. 2

   Trust Instantly in the Google Admin console

   At admin.google.com go to Security → Access and data control → API controls → Manage app access → Configure new app. Paste the Client ID into the search (searching for the name does not work), select Instantly's app, apply it to all users (or the right organisational unit) and set access to Trusted.

3. 3

   Sign in each mailbox

   Back in Instantly, choose the OAuth option, click Login, pick the mailbox and click Allow. If only the admin account appears, use 'Use another account' or an incognito window. Repeat for each mailbox.

Connect Google Workspace to Smartlead

Smartlead offers Google OAuth (using Smartlead's shared app or, for larger setups, your own 'private' OAuth app created in Google Cloud) and manual SMTP/IMAP with an app password. For OAuth, add the mailbox from Email Accounts and approve every permission screen. If a connection shows an error, Smartlead suggests disconnecting and reconnecting, and for SMTP trying port 587 (TLS) or 465 (SSL).

Connect with an app password (one mailbox)

1. 1

   Make sure IMAP is allowed

   A Workspace admin must allow IMAP access for users in the Admin console (Apps → Google Workspace → Gmail → End User Access).

2. 2

   Turn on 2-Step Verification for the mailbox

   Sign in to the mailbox's Google Account → Security → 2-Step Verification. App passwords only appear once this is on, and the organisation must allow users to turn on 2-Step Verification.

3. 3

   Create an app password

   In the Google Account, create an app password and copy the 16-character code. Store it securely; it gives mail access without the main password.

4. 4

   Enter the IMAP and SMTP settings in your sequencer

   Username = full email address, password = the app password. IMAP host imap.gmail.com, port 993 (SSL). SMTP host smtp.gmail.com, port 587 (TLS) or 465 (SSL).

Bulk import dozens of mailboxes by CSV

Both tools accept a CSV of IMAP/SMTP mailboxes. In Instantly: Email Accounts → Add New → Connect existing accounts → Any Provider → Bulk Import from CSV; Instantly notes that for Google accounts you use each mailbox's app password as both the IMAP and SMTP password. In Smartlead: Email Accounts → Add Account(s) → bulk upload, following Smartlead's sample CSV; the preview flags bad rows (for example a missing password) so you can fix or skip them. Instantly's help centre notes that Microsoft 365 / Outlook accounts cannot be bulk imported and must use its Microsoft OAuth connector.

1. 1

   Get a CSV in the right column format

   Download the sequencer's template, or use a provider export that already matches it. Columns cover email, sender name, IMAP and SMTP host, port, username and password, and usually a daily limit and warmup setting.

2. 2

   Check limits before uploading

   Set a conservative daily sending limit per mailbox. Decide whether the sequencer's warmup should run, especially if your provider already warms the mailboxes.

3. 3

   Upload and review the preview

   Fix or skip rows the tool flags, then import. Watch the status page until all mailboxes show as connected.

4. 4

   Spot-check a few mailboxes

   Send a test from two or three mailboxes and confirm replies arrive in the sequencer's inbox view.

5. 5

   Delete the CSV

   The file contains mailbox passwords. Delete it from your downloads and do not share it in chat or email.

How ReplyDak's CSV export helps

ReplyDak creates Google Workspace mailboxes on authenticated, warmed domains and lets the workspace owner export them as CSV in three formats: Instantly, Smartlead and a generic CSV for other sequencers. The Instantly and Smartlead files use the column names those tools' bulk import expects, with Gmail's IMAP/SMTP hosts and ports filled in and a default daily limit of 30 per mailbox that you can edit before uploading. Instead of setting up each mailbox by hand, you download one file and import it. Treat the file like a password list and delete it after import.

Common errors and fixes