Most OptiPub clients come onboard with an existing subscriber list from a previous provider. Getting those subscribers into OptiPub and sending to them successfully requires a careful, phased approach — not a single bulk import.

Why You Can't Import Everything at Once

Every OptiPub account is provisioned with dedicated IP addresses and sending domains. Because these IPs are brand new, mailbox providers (Gmail, Outlook, Yahoo, etc.) have no sending history to judge them by. Sending a large volume of email from an unestablished IP will almost certainly result in deliverability problems — throttling, spam folder placement, or outright blocks.

This is where IP warmup comes in.

The Warmup Process

IP warmup is the practice of gradually increasing your email volume over several weeks so mailbox providers can build a positive reputation for your new IPs. A typical warmup looks like this:

Throughout this process, key metrics are monitored closely:

• Bounce rates — High bounces signal list quality issues.
• Spam complaints — Complaints damage IP reputation quickly.
• Inbox placement — Confirms messages are landing in the inbox, not spam.
• IP reputation — Tracked in OptiPub via Postmaster+, which aggregates data from Google Postmaster Tools, Outlook SNDS, and other sources.

OptiPub manages warmup hands-on. We strongly recommend giving the OptiPub team access to your current email provider so we can handle segmentation, exports, imports, and volume pacing for you. This ensures the warmup succeeds and your sender reputation is protected from day one.

Importing Subscribers in Phases

As warmup progresses, subscribers are imported into OptiPub in batches using Segments. Each phase typically involves:

1. Exporting a segment from your current provider (e.g., subscribers who opened an email in the last 30 days).
2. Importing that segment into OptiPub via the web console.
3. Sending to the new segment from your OptiPub account and monitoring results.
4. Repeating with a larger, less-engaged segment once metrics look healthy.

How to Import a Segment

1. Navigate to Messaging > Segments.
2. Create a new static segment or select an existing one.
3. Click the Import button on the segment row to open the import wizard.

The import wizard walks you through three steps:

1. Upload — Upload a .csv file (up to 100MB) or paste CSV data directly.
2. Map Columns — Map each column to an OptiPub field. At minimum, map the Email column. You can also map Variables, Tags, and subscription metadata.
3. Configure Options — Set subscription status, source campaign, source partner, and other import settings.

For a detailed walkthrough, see Importing to a Segment.

Other Import Methods

Once warmup is complete and you're at full volume, you can use these methods for ongoing subscriber acquisition: