Harp vs Smartlead
Smartlead is a cold email platform built around unlimited mailboxes at no extra cost, AI warmups and a master inbox, with an API and webhooks. Harp is the harness your agent runs outbound through, across email and LinkedIn.
The short answer
If you run cold email across many mailboxes and want strong infrastructure for it, Smartlead is built for that. If your agent should research, sequence across email and LinkedIn, and answer replies within minutes, Harp is built for that.
Side by side
| Topic | Harp | Smartlead |
|---|---|---|
| What it is | The MCP harness for pipeline generation: research memory, sequences, sending, replies and LinkedIn, driven by your AI agent | Cold email infrastructure with unlimited mailboxes |
| Your Google Workspace mailbox: 28-day warm-up, 2 to 6 minutes between sends, recipient working hours, plain text, one-click unsubscribe | Unlimited mailboxes, AI warmups, master inbox | |
| Steps run from your real Chrome on your Mac at the OS level: click navigation, daily limits, a four-week warm-up and a right-person check | Not listed | |
| Replies | The sequence stops; your agent answers email replies and books the meeting within minutes. LinkedIn replies wait for your yes in Slack | Master inbox |
| Buying | Flat subscription after a short call; set up with you | Public plans from $39 a month |
Infrastructure vs an agent loop
Smartlead gives you the pipes for sending a lot of email. Harp gives your agent the loop: research with evidence, sequences across email and LinkedIn, sending with a careful pace, and replies answered within minutes.
When Smartlead is the better choice
- You send at volume across many mailboxes.
- You want email infrastructure on a low monthly plan.
- You do not need LinkedIn.
When Harp is the better choice
- You want LinkedIn and email in one sequence.
- Your agent should research every account first.
- You want replies answered, not just collected.
Questions
See Harp on your own outbound
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