Before joining, I was struggling with 15-16% open rates and wasting money on incorrectly set up email systems. Now I'm achieving 76% open rates — numbers I never imagined possible.
Nikolas NariciFounder, Visioninbox
Isolated nameservers and domain masking, included on SMTP and Google WorkspaceIsolated nameservers + masking included See how
Built for cold email deliverability
Cold Email Mailboxes That Land In The Inbox.
Done-for-you cold email mailbox infrastructure that lands in the inbox, trusted by the biggest names in lead generation.
Works with Your Favorite Cold Email Tools
How it works
From sign-up to landing in the inbox.
No DNS dashboards, no Workspace admin, no spam-folder detective work. Here is the whole flow.
Order placed · 9 mailboxes
Hyperboxes on Easy Mode: instant setup, live within minutes. Warmup then ramps over 21 days.
Deliverability
Your own nameservers. Masked domains. In the base price.
Two protections that each remove a signal that gets cold domains flagged. Both sit on top of our SPF, DKIM, DMARC, BIMI and warmup setup, and both are in the base price.
Isolated nameservers
IncludedBlocklists group domains by shared nameservers, so one listing can hit every domain in the pool. Yours run on a nameserver set scoped to your account, never pooled with other customers' cold domains.
Bring your own domains (Full Control) and they stay at your registrar; we publish the mail records into your zone. Already on your own Cloudflare account? You have this. Microsoft 365 runs on a separate dedicated account.
Domain masking
IncludedA blank page on a sending domain is a red flag. Masking serves your real website there instead. On by default for eligible orders, with every domain's status in your portal.
- 1Someone opens your sending domain.
- 2Our edge serves your real website on that same domain.
- 3The domain looks like the business it is.
Eligible today: Hyperboxes and Google Workspace orders placed self-serve on Easy Mode. Full Control, agency-placed and Microsoft 365 orders are not masked at order time.
Both reduce one risk. Neither stops spam filtering or promises inbox placement. Below is what we measure.
Where your emails land, by recipient
Test messages go to seed inboxes at every major provider, and we count where they land.
Landed in the inbox · 30-day rolling
Google Workspace0.0%
Microsoft 3650.0%
Other providers
0.0%
30-day rolling placement across 25,000+ deployed mailboxes, by recipient provider.
New · Claude Skill + CLI
Spin up perfect mailboxes in Claude Code.
One command gives Claude Code, Cursor or any agent the tools your team uses: domains, mailboxes, DNS checks and credential export.
- 9 mailboxes ordered and warming from one chat
- Charges your saved card, no human queue
- Auto-uploads to Instantly or EmailBison when done
you ›Order 9 SMTP mailboxes for growthrange.com and warm them up.
claude ›Suggesting 3 domains · checking availability
→ inbox_insiders.suggest_domains ✓ growthrange-mail.com · growthrange-hq.com · getgrowthrange.com
→ inbox_insiders.create_order ✓ 9 mailboxes · Hyperboxes (SMTP) · isolated nameservers
→ inbox_insiders.poll_status ✓ DNS verified · warmup started
✓9 mailboxes ordered, warmup started. Credentials exported to Instantly.
Reviews
What 4,200+ founders say about our mailboxes.
From leadgenjay.com/reviews. Real names, real campaigns.
4.9
★★★★★213+ verified reviews · 98% 5-star
I just wanted to commend the team. The experience was incredibly easy — and all the mailboxes got set up for me.
Sami Ahmadscaleyourresults
Within about 30-45 days in the program I doubled what I had been making on average for the previous six months. The cold outreach systems are the best I have seen.
TM
Tom MeitnerSelf Employed
Before this, I was getting about 30% open rates for my clients. Already I'm getting 50%+ open rates and my client is very happy.
A
AugustinasEmail Operator
Results
Real campaigns. Real replies.
Snapshots from leadgenjay.com/results, running on Inbox Insiders mailboxes. Results vary.
Home Services145 Opportunities · $635K Pipeline
Michaels and Marc Restoration
Denver roofing contractor generated 145 opportunities worth $635,000 from cold email outreach with 8.3% reply rates on the top-performing segment.
Read case study →
Construction Staffing0.5% → 5.8% Reply Rate
Econsultify
Nathan Doan transformed a construction staffing client's cold email results from 0.5% to 5.8% reply rates using AI-enriched campaigns and Inbox Insiders mailboxes.
Read case study →
Real Estate$689K+ Pipeline · 3.3% Reply
Qazzoo & USHUD
Real estate platform generated $689K+ in pipeline from cold email with 3.3% reply rates and 2,900 opportunities; top campaign hit 13% reply.
Read case study →Pricing
Choose your email infrastructure.
Pick your infrastructure. Pause, scale or cancel any time. Isolated nameservers and domain masking are in the base price on Hyperboxes and Google Workspace.
Masking is switched on for orders placed from your account. Guest checkout does not turn it on automatically.
Instant setup
Hyperboxes (SMTP)
Premium mailboxes using private servers with managed IPs for best deliverability.
30 emails/day per mailbox1 domain per 3 mailboxes$3 setup fee per mailboxIsolated nameservers includedDomain masking included
$3.50/mailbox
per month
Google Workspace
High deliverability with Gmail infrastructure.
30 emails/day per mailbox1 domain per 3 mailboxes$3 setup fee per mailboxIsolated nameservers includedDomain masking included
$3.50/mailbox
per month
Microsoft 365
Enterprise-grade Outlook infrastructure with bulk pricing.
5 emails/day per mailbox1 domain per 49 mailboxes$10 setup fee per domainDedicated Microsoft 365 account included–Domain masking not available on Microsoft 365
$30/49 mailboxes
per month
Start your order
Running 100+ mailboxes? See volume pricing
FAQ
Common questions.
Hyperboxes on Easy Mode: instant setup, live within minutes. Domains register, DNS verifies, and a 21-day warmup starts automatically. You get a credentials export once everything is green.
Across 25,000+ deployed mailboxes, 30-day rolling placement on Google Workspace is 98.2%, with 1.8% landing in spam. The Deliverability section above breaks it down by provider.
No. We register the domains, configure every DNS record, run the warmup and hand you working credentials. If something drifts out of spec, we fix it. That is what the monthly per-mailbox fee covers.
Yes. Pick Full Control and supply domains you own. They stay in your registrar account and we publish the mail records into your zone. Easy mode registers fresh .com domains for you ($12 each).
No. We serve your existing website through our edge on each masked sending domain. Nothing to install, no DNS work, no code on your site.
No. Your website stays where it is. Masking only changes what people see when they visit a sending domain. They get your real site instead of a blank page.
One curl command installs our skill into ~/.claude/skills and Claude Code learns the API: domain suggestions, availability checks, ordering (SMTP or Google Workspace), status polling and credential export. It uses your dashboard login and charges your saved card. A zero-dependency CLI is included.
Auto-upload works with Instantly, EmailBison and PlusVibe, from the order form or the API/CLI. PlusVibe also needs your 24-character workspace ID. Smartlead, Lemlist, Reply and any tool that accepts custom mailboxes connect through standard SMTP/IMAP.
Yes, month to month from your portal. For eligible orders, cancelling records the request and starts our shutdown process straight away. Pre-warmed orders carry a 3-month minimum, and orders with an open credit request go through support first. Domains you brought stay in your registrar account. Eligible active Easy Mode domains we registered for you can be transferred from the portal once the 60-day registrar lock has passed. Agency clients ask their agency admin.
Ready to land in the inbox?
Order in the app, or let Claude Code place the order.