Cold Outreach · Growth plan and above
Outbound that
replies at scale.
Connect your real inboxes. Build multi-step sequences. Rotate through them. Auto-stop when someone replies. Classify every reply with AI. MailerSpark is the cold outreach layer your CRM doesn't have.
Gmail + Microsoft 365 + any SMTP/IMAP · Stop on reply · Per-inbox throttling
Multi-step sequences
Build a sequence,
not a single blast.
A sequence is an ordered set of steps. Each step is a wait followed by a personalized subject and email. You can A/B test, add conditional branches, and define stop-on-reply rules at the campaign level.
- Wait days + step contentDay 1, Day 3, Day 7, Day 14 — each with its own subject, body, and merge tags. Reorder by drag-and-drop.
- A/B variants per stepTest two subject lines on the first step. The winner moves to the rest of the list automatically.
- Stop on reply (default)The moment a prospect replies, the sequence stops — no double-sending, no awkward 'just bumping this' follow-ups.
- Unsubscribe links (optional)You can opt in to a CAN-SPAM unsubscribe footer for cold emails. We honor every opt-out across future sends.
Inbox rotation & warmup
Spread volume across
every connected inbox.
Connect as many mailboxes as you have. MailerSpark sends from the right inbox for the right recipient, throttles per-inbox daily and hourly limits, and gradually ramps new domains so they don't get throttled.
- Priority or round-robinPick priority order or strict round-robin per campaign. Match by recipient domain with provider matching.
- Warmup rampSet a start date and MailerSpark auto-increments daily volume. Day 1: 5 sends. Day 14: 50. Day 30: 250.
- Per-inbox throttlingDaily and hourly caps per inbox keep you under the limits that trigger Gmail's / 365's spam filters.
- Health monitoringToken expiry, last error, and warmup day are surfaced on the Inboxes page so you catch problems early.
Proxy rotation
Rotate the SMTP
egress IP per send.
Residential and datacenter proxies rotate the originating IP that your SMTP server uses. Lower bounce rates, fewer spam flags, and the ability to send from a wide IP pool without managing infrastructure.
- SOCKS4 / SOCKS5 / HTTP / HTTPSAny proxy type that speaks those protocols. Add proxies in Settings → Proxies, with passwords encrypted at rest.
- Per-send rotationEvery SMTP connection picks a fresh proxy. You set the cadence: per send, per inbox, or per campaign.
- Free of vendor lock-inBring your own proxies. We don't resell IP space. If you already pay for residential IPs, plug them straight in.
AI reply classification
Replies sorted before
your team sees them.
Every reply that lands in the Unibox is classified by AI as Interested, Not Interested, Out of Office, Wrong Person, or Auto-Reply. Your team works the Interested pile first. The rest is filtered but searchable.
- OpenAI, Ollama, or heuristicBring your own OpenAI key, point at a local Ollama model, or use the built-in heuristic fallback. No vendor lock-in.
- Per-thread contextSee the full conversation, the original sequence step, and the lead record — without leaving the inbox.
- Lead status pipelineClassified replies can auto-transition leads from contacted → interested. The CRM stays in sync.
Get started
Your first sequence in 15 minutes.
Growth plan and above
Cold outreach is in the platform.
Unlocked on Growth ($49/mo) and above. No separate tool to buy, no separate login, no separate suppression list.