Cold email infrastructure for outbound teams & email marketing agencies.
Cold email infrastructure for outbound teams — authorized Google Workspace & Microsoft 365 mailboxes, automated DNS, full ownership, connects to any sending tool. The trusted email campaign management and marketing automation platform for fast-growing US & UK outbound sales.
Outbound Provisioning
Instant Box Calculator
TOTAL MONTHLY INVESTMENT
$4.00 / mailbox / month · Billed monthly · Cancel anytime
POWERING OUTBOUND REVENUE TEAMS ACROSS THE UNITED STATES & UNITED KINGDOM
Engineered for American & British B2B Sales Teams
Strict adherence to US & UK deliverability guidelines, ISP trust networks, and legal compliance.
Local US & UK Relay Clusters
Relay nodes situated directly in Ashburn (US East), Chicago (US Central), and London (UK). Proximity to major corporate MX exchanges ensures sub-100ms SMTP connections with zero geo-mismatch warnings.
CAN-SPAM & UK GDPR / PECR
Every mailbox setup includes ready-to-use DNS blueprints with strict SPF/DKIM/DMARC alignment required by the latest 2024–2026 Google & Yahoo bulk-sender mandates across North America and Europe.
Zero Shared-Tenant Contamination
Unlike reselling Google Workspace accounts where one customer’s ban risks sister domains, WarmedInboxes provides isolated IP sockets with dedicated Postfix routing for total operational independence.
"We run cold outreach for 18 B2B SaaS clients across the US. Switching from Google Workspace to WarmedInboxes reduced our inbox infrastructure overhead from $700/mo to $180/mo while maintaining a 96% inbox placement."
"UK enterprise prospects are notoriously difficult to reach. Having low-latency London relays and proper DMARC quarantine policies in place meant our emails landed directly in the primary inbox of FTSE 250 decision makers."
Average Primary Inbox Rate
Across 1.8M+ emails relayed each month in US & UK
Why standard Google Workspace and Microsoft 365 setups are breaking outbound campaigns
When you send cold emails through native Google or Microsoft tenants, you share IP pools and tenant flags. One high-volume burst triggers automated tenant restrictions, burning your main domains. WarmedInboxes isolates every 6 domains onto dedicated IP sockets with managed Postfix relays to ensure maximum deliverability.
WarmedInboxes vs. Typical Providers
Compare managing outreach infrastructure yourself versus receiving managed pre-warmed accounts.
Managed & Pre-Warmed
Engineered specifically around B2B cold outbound workflows with deliverability guards.
- ✓Pre-warmed mailboxes prepared before delivery — zero waiting period
- ✓Warmup included at no extra cost while your mailbox remains active
- ✓Use your own business domain with full SPF, DKIM 2048, and DMARC alignment
- ✓Dedicated IP socket isolation (strict 6 domains per IP socket rule)
- ✓Real-time Auto-Guard bounce protection threshold at 15.0%
- ✓Single-pane client portal with 1-click CSV export into Instantly & Smartlead
- ✓100% Mailbox Replacement Guarantee if deliverability drops
Build It Yourself
Customer handles all technical setup, warming, and management manually.
- ✕Manual account provisioning and per-user billing overhead ($6–$7.20/box)
- ✕14–21 days waiting delay building reputation from absolute zero
- ✕Requires purchasing separate email warmup tools ($5–$15/box extra)
- ✕High risk of complete Google Workspace or Microsoft 365 admin account ban
- ✕Manual DNS configuration (SPF, DKIM, DMARC) with technical troubleshooting
- ✕Dispersed across multiple separate dashboards and tools
- ✕Zero bounce protection — one dirty lead list burns the entire domain
Works with Every Outreach Tool
Connect your WarmedInboxes accounts into your favorite cold email sequencer using standard SMTP/IMAP credentials or 1-click CSV upload.
Instantly.ai
1-Click CSV Upload
Smartlead.ai
Bulk SMTP / IMAP
Lemlist
Direct Credentials
Apollo.io
Custom Mailbox
Mailshake
Native IMAP / SMTP
Woodpecker
Outbound Relay
Breakcold
CRM Sync
Custom Scripts
Direct Node API
Lower your cost as you scale.
Scale from 10 to 500+ pre-warmed accounts with volume pricing and dedicated US & UK IPs.
$4.00 (~£3.15)
10–49 Inboxes
$4.00 (~£3.15)
50–99 Inboxes
$3.75 (~£2.95)
100–249 Inboxes
$3.50 (~£2.75)
250+ Inboxes
RECOMMENDED DOMAINS
5 domains
5 inboxes per domain
DAILY SEND CAPACITY
750 – 1,250/day
22,500 – 37,500/mo
🔥 Peer Warmup Included Automatically
Every active WarmedInboxes mailbox includes full automated warmup support at zero extra charge.
TOTAL MONTHLY PRICE
$100.00 /mo
Approx. £79.00 / month (UK billing)
25 MAILBOXES × $4.00
Live and sending in three steps.
From configuration to active campaigns in under 24 hours.
Provide Your Domain
Select your mailbox volume and provide your secondary sending domain(s). We generate exact DNS records.
We Provision & Pre-Warm
Our engine provisions mailboxes, binds them to isolated IP sockets, and runs warmup routines before handover.
1-Click CSV & Start Sending
Download your CSV with credentials pre-formatted for Instantly, Smartlead, or Lemlist. Connect and launch.
Watch How Easy It Is to Launch 50 Mailboxes
Step-by-step export into Instantly.ai (2 min walkthrough)
From order to sending, without the busywork.
Multi-layered deliverability guards enforced directly on Postfix relay nodes.
Automated Mailbox Provisioning
Receive your pre-warmed mailbox credentials with single-click CSV export ready for immediate import into Instantly.ai, Smartlead.ai, or custom outreach tools.
Peer Warmup Included
Warmup routines remain active for the life of your mailbox subscription without third-party fees.
INBOX HEALTH SCORE
● 100% HEALTHY
0 Blacklist Flags
Zero DNS Headaches, Fully Aligned
v=spf1 include:_spf.warmedinboxes.com ~all
RSA 2048-bit Cryptographic Key
v=DMARC1; p=quarantine; pct=100;
Answers to common questions.
Frequently asked questions by sales leaders and agency founders across the US & UK.
Need a Custom Setup or Dedicated IP Pool?
Send our outbound infrastructure engineers a direct inquiry. We respond within 2 hours.
Deploy pre-warmed mailboxes on your domain today.
Skip the 14-day warmup delays. Connect your accounts to Instantly or Smartlead and launch your US and UK outbound campaigns with peace of mind.