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Short answer
Connect Instantly with its API key in Outreach2day (Export to sequencer) and export the mailboxes in one click; they appear in Instantly as custom IMAP/SMTP accounts, and new ones follow automatically. Or download the Instantly CSV and use Instantly's Bulk Import from CSV. Send up to 25 cold emails per mailbox a day; warm-up keeps running in Outreach2day.
What you get
- Outreach2day mailboxes added to Instantly with its API key, one click for all of them or a selection
- Auto export: new mailboxes go to Instantly as soon as they are created
- Auto reconnect: mailboxes that disconnect in Instantly are reconnected
- A CSV in Instantly's import format as the manual route
- Warm-up keeps running in Outreach2day after the export, included in the price
- SPF, DKIM and DMARC already set on every domain
Connect Instantly and export
In Outreach2day
- Open Export to sequencer. In the app sidebar, open Export to sequencer and click Connect sequencer
- Pick Instantly and paste its API key. Fill in the connection name, your Instantly login email and password and the API key, then click Check key. Export, auto export and reconnect need the key
- Choose the settings. Auto export (new mailboxes as soon as they are created), Auto reconnect, and the mailbox scope (all mailboxes or one tag); with a key that has workspace-group access, also the Instantly workspace
- Export. Export all eligible mailboxes or a selection. Mailboxes still being set up, deactivated or frozen are skipped, and mailboxes already exported to this connection are not sent twice
The same works from an AI assistant: with the Outreach2day MCP server, list_sequencers shows the connection and export_mailboxes_to_sequencer exports the mailboxes after you confirm. From code, use the sequencer endpoints in add email accounts to Instantly or Smartlead via API.
In Instantly
- Create an API key. In Instantly, create an API key in the workspace settings and copy it into the Outreach2day connection (see Instantly's API docs) (developer.instantly.ai)
- Check the accounts. After the export the mailboxes are listed under Email Accounts as IMAP/SMTP accounts. Instantly requires both IMAP and SMTP on every account (help.instantly.ai)
- Or import the CSV. Email Accounts > Add or Buy Accounts > Connect existing > Any Provider > Bulk Import from CSV, map the fields and click Upload All (help.instantly.ai)
- Add them to a campaign. Select the accounts in the campaign's sending options and set the campaign daily limit (help.instantly.ai)
Fields in the Instantly CSV
The file from the Instantly export has these columns (the one-click export sends the same settings through the API):
| Column | Value |
|---|---|
Email | The mailbox address |
First Name | Sender first name |
Last Name | Sender last name |
IMAP Username | The mailbox address |
IMAP Password | The mailbox password |
IMAP Host | outreachmailstream.com |
IMAP Port | 993 |
SMTP Username | The mailbox address |
SMTP Password | The mailbox password |
SMTP Host | outreachmailstream.com |
SMTP Port | 465 |
Daily Limit | 20 |
Warmup Enabled | TRUE |
Warmup Limit | 20 |
Warmup Increment | 3 |
- The 15 columns are the ones in Instantly's own sample sheet, in the same order
- Daily Limit is 20 in the file; raise it to 25 after the ramp. Instantly's help center suggests 30 campaign emails a day per account in general; for Outreach2day mailboxes we recommend 25
- Warmup Enabled TRUE turns on Instantly's warm-up as well. Outreach2day warm-up already runs on these mailboxes, so you can set it to FALSE; if you keep it, Instantly suggests 10 warm-up emails a day and allows a Warmup Increment of at most 4
Connection settings
To add a single mailbox by hand, or to check what Instantly saved, use these settings:
| Field | Value |
|---|---|
| SMTP host | outreachmailstream.com |
| SMTP port | 465 (SSL/TLS) |
| IMAP host | outreachmailstream.com |
| IMAP port | 993 (SSL/TLS) |
| Username (SMTP and IMAP) | The full email address |
| Password (SMTP and IMAP) | The mailbox password from the export (the same for SMTP and IMAP) |
Sending settings per mailbox
- Mailboxes can send cold email 14 days after warm-up starts; warm-up keeps running after that
- Up to 25 cold emails per mailbox a day, warm-up not counted
- Start low on day 14 (for example 5 a day) and reach 25 around day 21
- To send more, add mailboxes and domains; keep the per-mailbox number at 25
Where to set it in Instantly:
- Per account: Email Accounts > select the account > Settings > Daily Campaign limit (set 25) and Minimum wait time (default 1 minute) (help.instantly.ai)
- Per campaign: Campaign Settings > Schedule & Limits; Instantly's formula is the number of accounts times the per-account limit (help.instantly.ai)
- Campaign Slow Ramp: the account starts lower and adds 2 campaign emails a day until it reaches its daily limit (help.instantly.ai)
Why 25: how many cold emails one mailbox should send a day. The day-by-day ramp: email warm-up schedule.
Warm-up
Warm-up for Outreach2day mailboxes runs in Outreach2day and is included in the price. It keeps running after you export the mailboxes, whichever tool sends from them, so the other tool's warm-up is optional.
- Instantly's warm-up settings per account: Increase per day (default 1), Daily warmup limit (default 10), Reply rate % (default 30), Weekdays only mode (help.instantly.ai)
- Path: Email Accounts > select the account > Settings > Warmup settings (help.instantly.ai)
Keep warm-up on while the mailbox sends: should I keep warm-up running while sending.
DNS and tracking domain
- SPF, DKIM and DMARC for every Outreach2day domain are set and checked automatically; you add nothing for sending
- A custom tracking domain is a CNAME on a subdomain of your sending domain. For a domain whose DNS Outreach2day hosts, add it in the app: Domains, open the domain, Manage DNS records, Add record (type CNAME). For a domain whose DNS stays at your registrar, add it there
- A tracking domain matters only with open or click tracking on. In the first cold email, leave out the tracking pixel and links and measure replies (see the answer on open tracking below)
- Instantly's custom tracking domain is a CNAME with host inst pointing to prox.itrackly.com, so the tracking domain is inst.yourdomain.com; the host must be exactly inst (help.instantly.ai)
- Turn it on in Email Accounts > select the account > Settings > Custom tracking domain, enter inst.yourdomain.com, save and click Check Status until it shows CNAME Verified (help.instantly.ai)
More on tracking: do open tracking and links hurt cold email deliverability.
Troubleshooting
| Error or symptom | Fix |
|---|---|
| Account already added to this or a different workspace | Instantly accepts an address in one workspace only. Remove it from the other Instantly workspace, or pick that workspace in the Outreach2day connection. Outreach2day skips these mailboxes and checks them again every hour |
| IMAP/SMTP connection fails when you add the account | Instantly's advice is to recheck credentials, server addresses and ports, since typos are the most common cause (help.instantly.ai) |
| DNS Error on the account | Run Test Domain Setup in Email Accounts, then delete and reconnect the account. On Outreach2day domains the records are managed for you; if the test fails, check the domain in Outreach2day (help.instantly.ai) |
| Hit your daily email sending limit | Instantly suggests lowering the volume per account and varying the copy; it usually clears in 24 to 48 hours (help.instantly.ai) |
| Authentication failed / invalid credentials | Use the full email address as the username and the password from a fresh export. A disabled mailbox is exported with an empty password, so it can't connect |
| Connection timed out or SSL/TLS handshake error | Use SMTP port 465 with SSL/TLS and IMAP port 993 with SSL/TLS, both on outreachmailstream.com. Check that the tool did not switch the security setting to STARTTLS or none |
| Mailbox connects but can't send yet | Check the mailbox in Outreach2day: new mailboxes are being set up for up to 24 hours, and cold email starts 14 days after warm-up starts |
| Mailbox disconnected after it worked | Reconnect it in the tool with the same settings. With a one-click connection (Instantly, Smartlead) and auto-reconnect on, Outreach2day reconnects it for you |
If bounces climb after the mailboxes connect, look at the list: why a cold email bounce rate gets too high.
FAQ
Is the Instantly export included in the Outreach2day price?
Yes. Connecting Instantly, exporting mailboxes, auto export and auto reconnect are included for every Outreach2day account at $2.50 per mailbox a month. You pay Instantly for your Instantly plan.
What does Outreach2day send to Instantly?
For each mailbox: the address, sender first and last name, and the IMAP and SMTP username, password, host and port, created through Instantly's API as a custom IMAP/SMTP account (provider code 1). The API key is stored encrypted.
Can I export to several Instantly workspaces?
Yes. Create one connection per Instantly API key. With a key that has workspace-group access, the connection also lets you pick the Instantly workspace.
Do I need Instantly's warm-up?
No. Warm-up for Outreach2day mailboxes runs in Outreach2day and keeps running after the export. Instantly's warm-up is optional.
Can I skip Instantly and send from Outreach2day?
Yes. Outreach2day has its own campaigns with steps, contacts, stats and a reply inbox. The Instantly export is for teams that already run their campaigns in Instantly.
Sources
Instantly documentation, read on 2026-10-09. Menus and field names change; if a step differs, Instantly's own page is the reference.
- Instantly: Bulk import sending accounts into Instantly: help.instantly.ai/en/articles/6687763-bulk-import-sending-accounts-into-instantly
- Instantly: Connecting other SMTP providers: help.instantly.ai/en/articles/7878219-connecting-sendgrid-mailgun-and-other-smtp-providers
- Instantly: Account and campaign limits: help.instantly.ai/en/articles/6248612-account-and-campaign-limits
- Instantly: Warmup settings: help.instantly.ai/en/articles/7988514-warmup-settings
- Instantly: Custom tracking domain: help.instantly.ai/en/articles/6984188-custom-tracking-domain-ctd
- Instantly: How to fix disconnected email accounts: help.instantly.ai/en/articles/7896857-how-to-fix-disconnected-email-accounts
- Instantly API: Create account: developer.instantly.ai/api-reference/account/create-account
