I’ve used both Smartlead and Instantly pretty extensively here’s the simple breakdown:
👉 Smartlead
Best for large sending volumes + inbox rotation
Super flexible API + automations
Weak on engagement-based segmentation (opens/clicks/replies aren’t great for triggering automated logic)
Follow-up sequencing is solid but not behavior-driven
👉 Instantly
Much stronger on engagement signals
You can build automations based on:
Makes it really easy to route leads into follow-up sequences automatically
Cleaner UI + easier reporting
Not as advanced for multi-inbox rotation as Smartlead
If engagement-based automation matters to you, Instantly is much stronger.
If high-volume sending + infrastructure matters most, Smartlead wins.