Mailheight: cold email that actually lands.
Mailheight is the deliverability-first platform LeadSourcing runs every client campaign through. Prospecting, validation, AI-driven research and writing, sending, and reputation protection, working as one connected system instead of five disconnected tools.
AI does the research. AI writes the email. Per prospect, every time.
Nothing that goes out is a mail-merge template with a first name swapped in. Before a single line gets written, the AI has already done the homework, twice: once on the client sending the email, once on the person receiving it.
- Reads the client's own website to learn what they actually sell, no separate briefing document required
- Researches each prospect's company individually before a word gets written, not once per list, once per lead
- Ties the opening line to a real, current signal about that specific company, not a generic hook that could go to anyone
- Placeholder guard blocks any invented detail from ever reaching a draft
- Every email is drafted first and approved by a human before it sends, never fully autonomous
01 client site scanned → "what we sell" extracted
02 prospect: Priya Sharma, VP Marketing, Acme Cloud
signal found Acme Cloud opened an EU sales office this quarter
03 opening line grounded in that signal, not a template
draft → human approval nothing sends unreviewed
Most cold email dies before anyone reads it.
Unverified lists
Hit spam traps and dead mailboxes, and the mailbox provider remembers.
Generic blasts
Read like spam because there is no research or relevance behind them.
DIY infrastructure
DNS, warm-up, and monitoring eat agency hours before one email sends.
And on shared infrastructure, one careless campaign can poison sending for every other client sitting on the same setup. Mailheight is built around isolating that risk.
Every message follows the same protected pipeline.
Find: prospect and organize
Search a built-in prospect database by filters, bulk-match by domain or company, or query it in plain language with AI search. Imports land in client folders with automatic job-function tagging.
- Filter search and bulk domain match
- AI natural-language search
- CSV import with custom fields
Verify: validate every address
Per-list verification buckets every contact as valid, catch-all, unknown, invalid, or spam trap. Traps are removed before they ever reach a send queue.
Personalize: AI writes grounded copy, per customer profile
The AI extracts what a client sells from their own website, researches each individual prospect's company, then writes per-lead copy tied to that specific research. A placeholder guard blocks invented details, and nothing sends without approval.
- Website extraction and company research
- Placeholder guard against invented details
- Draft-then-approve on every send
Protect: reputation controls on every send
A global suppression list is shared across campaigns, bounce parsing separates hard from soft, sends stay inside business-hours windows, and per-sender daily and hourly caps keep volume in safe territory.
Send: sequences that adapt
Multi-step drip sequences with conditional branches on opens and clicks, A/B testing across subject, from-name, body, and send time, sent through multiple providers and sender identities so no single mailbox carries the load.
Reply: stop the moment a human answers
Reply detection classifies genuine replies against bounces and auto-replies. Out-of-office detection pauses the sequence and resumes it later, so no follow-up ever lands on top of an answer.
| Step | Trigger | Recipients | Opened |
|---|---|---|---|
| 1. Intro | Sends as soon as campaign starts | 2,400 | 820 |
| 2. Follow-up 1 | 2 days later, fixed | 1,540 | 690 |
| 3. Follow-up 2 | 2 days later, fixed | 1,410 | 640 |
| 4. Follow-up 3 | 2 days later, fixed | 1,390 | 610 |
Metrics that count humans, not scanners.
Security gateways open and click every link before a prospect ever sees the email. Mailheight filters that noise out of the numbers we report.
- Opens, clicks, replies, bounces, and unsubscribes tracked per campaign
- Verified-open and verified-click filtering strips scanner activity from the numbers
- One-click CSV export of any segment or result set
Every client isolated. Nothing bleeds.
One client's list, suppressions, and results never touch another's.
Client folders
Contacts, campaigns, and results organized per client account, with clean separation by design.
Admin and member roles
Teammates get the access they need and nothing more.
Per-account data isolation
Data stays inside each account boundary, suppression and reporting included.
One platform. Every client. Deliverability first.
From prospect search to verified reply, with reputation protection at every step.