Harp vs Instantly
Instantly is cold email software for scale: unlimited email accounts and warmup, a 450M+ lead database, an AI reply agent on higher plans and the option to use your own LLM key. Harp is built for a different shape of outbound: fewer, researched emails from your own mailbox, with LinkedIn alongside and your agent doing the thinking.
The short answer
If you need to send cold email at volume across many inboxes, Instantly is built for that. If your agent should research every account, send from your own mailbox at a careful pace and answer replies within minutes, with LinkedIn in the same sequence, Harp is built for that.
Side by side
| Topic | Harp | Instantly |
|---|---|---|
| What it is | The MCP harness for pipeline generation: research memory, sequences, sending, replies and LinkedIn, driven by your AI agent | Cold email software with unlimited email accounts |
| Your Google Workspace mailbox: 28-day warm-up, 2 to 6 minutes between sends, recipient working hours, plain text, one-click unsubscribe | Unlimited email accounts and warmup | |
| Lead data | Not sold; your agent uses the tools you already use | A 450M+ B2B lead database |
| 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 | |
| AI | Your own agent (Claude today) on your own plan; no AI credits | AI agents including an AI reply agent; you can use your own LLM key |
| Buying | Flat subscription after a short call; set up with you | Public plans from $47 a month |
Volume vs precision
Instantly is built to send a lot of email across many inboxes. Harp is built for researched outreach: your agent qualifies every account with evidence first, and Harp sends from your own mailbox with a warm-up, spacing and recipient-local timing, then stops the moment someone replies.
When Instantly is the better choice
- You send cold email at high volume across many inboxes.
- You want lead data and warmup in one tool.
- You do not need LinkedIn in the sequence.
When Harp is the better choice
- You want LinkedIn and email in one sequence.
- Your agent should research every account before it is contacted.
- You send from your own Google Workspace mailbox.
Questions
See Harp on your own outbound
We set up every customer ourselves. Tell us how your team runs outbound today.
Talk to sales