Moving From Smartlead or Instantly to EmailBison: Clean the Lead List Before You Import

Why migrations cause bounce spikes

The cold email platform is where your list history lives. Smartlead and Instantly both mark leads that bounced, unsubscribed or replied, and both keep a block list. When you switch, the new tool starts from a blank slate. Teams typically export "the leads", upload them, and within a day have re-mailed people who bounced last month and people who asked to be removed.

On a new platform you often also have new sending inboxes, a different sending pattern and a warmup network that hasn't seen your mailboxes before. That combination makes the first week fragile. A list that would have bounced 2% in the old tool can trip a pause or a reputation drop now. See deliverability dropped after an ESP migration for the same problem on the marketing side.

Step 1: export with statuses, not just emails

From each campaign, export the full lead CSV including:

• email, first and last name, company, and every custom field
• lead status (for example: not started, in progress, completed, replied, bounced, unsubscribed)
• the last contacted date, if the export has it
• reply category or "interested" labels, if you use them

Smartlead and Instantly exports name these columns differently and both change over time, so open the file and check what you actually got. The Smartlead leads to email list and Instantly leads to email list tools read those exports and separate the addresses by status for you.

Also export, separately:

• the global block list or unsubscribe list from each tool
• any domain-level blocks (competitors, existing customers)

Building a suppression list from Smartlead shows where these live in Smartlead.

Step 2: split the leads into three groups

Group	Who	What to do
Never contact	Bounced, unsubscribed, marked "do not contact", spam complaints	Suppression file, permanently
Done	Replied (any reply), completed the sequence, meeting booked	Don't re-enroll; move to CRM or a later re-engagement plan
Active	Not started or mid-sequence	Candidates for import, after verification

Replied leads go in "done" even when the reply was "not now" or an out-of-office. Re-sending the first step of a sequence to someone who already answered looks careless and gets reported. Out-of-office replies with a return date can go back into a sequence later; see out-of-office replies in cold email.

Leads that were mid-sequence need a decision: start them at step 1 in the new tool (and accept that they get the opener twice), or start them at the step they had reached. Most platforms can't import a step position, so it's often simpler to put them into a short follow-up-only campaign.

Step 3: one suppression file, applied first

Combine both tools' block lists, the bounced and unsubscribed leads, and any CRM opt-outs in the suppression list merger. Keep a reason column.

Import that file into the new platform's block list or unsubscribe list before uploading any leads, so a later import can't slip past it. Check EmailBison's help docs for how its blacklist or blocklist import is named and whether it accepts domains as well as addresses. Then remove the same addresses from your active leads file with compare email lists as a second line of defence.

Step 4: map custom variables

Personalisation breaks quietly during migrations. Smartlead and Instantly both use double-brace variables, but the field names come from your CSV headers and templates, and the new platform may expect different syntax or casing.

1. List every variable your templates use.
2. Rename the CSV columns to match exactly what the new templates will reference.
3. Convert the template syntax with the merge tag converter if the new tool uses a different format or fallback syntax.
4. Check fill rates: any column that is blank for many leads needs a fallback value or a template that doesn't use it. The mail merge field checker catches empty fields before they go out as "Hi ,".

Step 5: re-verify stale leads

Email addresses decay: people change jobs, companies change domains, mailboxes are closed. Any lead verified more than a few months ago, or never verified, should be checked again before import.

Run the active group through verify. Then:

• Valid: import.
• Invalid: add to the suppression file.
• Catch-all / risky: the domain accepts every address, so the mailbox can't be confirmed. Put them in a separate, smaller campaign on inboxes you can afford to stress, or hold them back. See catch-all leads in sequences.
• Unknown: the server didn't answer clearly. Retry later rather than importing blind.

If you are staying on Smartlead for some campaigns, the Smartlead integration verifies leads inside your campaigns without exporting. For the migration itself, verifying the exported CSV once is simplest.

Step 6: reconnect inboxes and ramp

Your mailboxes live at Google Workspace, Microsoft 365 or your mailbox host, so you reconnect them in the new tool rather than rebuilding them. Warmup history inside the old platform's network doesn't come with you. For the first two to three weeks:

• start below the per-inbox volume you used before, then step up
• keep warmup running in the new platform
• watch bounces per inbox daily; pause any inbox that jumps

Email warmup schedules has ramp numbers you can adapt.

A migration checklist

1. Export leads with statuses from every campaign.
2. Export global block lists and domain blocks.
3. Split into never contact, done and active.
4. Merge and import the suppression file first.
5. Map custom variables and convert template syntax.
6. Verify the active leads; drop invalids, segment catch-alls.
7. Import, reconnect inboxes, ramp slowly.

What it costs

• Pro, $39 a month: Unlimited email verification.*
• Starter, $9 a month: 2,500 emails a month.
• Free: the first 100 checks with a Google sign-in, no card.

*Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.

Pro also includes the email finder, an API with 10,000 calls a month included and an MCP server for AI agents. The API, phone checks and the finder are not part of Unlimited. See pricing.

More reading: verify Smartlead campaign leads, Instantly and Smartlead list hygiene checklist.