Connect Lemlist

Updated Apr 15, 2026 · 3 min read

API key method and CSV fallback for Lemlist users.

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Lemlist is the third native integration alongside Smartlead and Instantly. Connect once with an API key; mailboxes flow in continuously.

Step 1 - Lemlist API key

In Lemlist, go to Settings → API & Integrations. Generate an API key with email-account read scope. Copy it.

Inboxlee dashboard → Integrations → Lemlist → Connect. Paste the key. Save. Live mailboxes flow into Lemlist within seconds.

Group mailboxes by domain in Lemlist for cohort sending.

Cap daily sends at 50 per mailbox for cold outbound.

Use Lemlist warmup with API toggle on - Inboxlee tracks the curve.

Verify reply detection is enabled - replies route back to the mailbox.