Puzzle Inbox — Pre-Warmed Cold Email Inboxes
Pre-warmed Google Workspace and Outlook inboxes for cold email outreach. DNS-ready, delivered in 24-72 hours. Starting at $0.35/inbox. Trusted by 1200+ clients with 70,800+ active inboxes.
Why Puzzle Inbox?
- Trusted Teams — Used by 1200+ agencies and sales teams
- Proven Results — 70,800+ active inboxes deployed
- Fast Setup — 24-72 hour delivery, ready to send
- Full DNS Configuration — SPF, DKIM, DMARC configured automatically
- Pre-Warmed Option — Skip 2-3 weeks of warmup, start sending immediately
- Platform Diversification — Both Google Workspace and Outlook 365 available
How It Works
- Order Inboxes — Choose Google Workspace or Outlook 365, standard or pre-warmed
- We Handle Setup — Domains, DNS records, SPF, DKIM, DMARC, and OAuth configuration
- Start Sending — Connect to your cold email tool via SMTP/IMAP and start sending
Pricing
- Outlook 365 Standard — $0.35/inbox
- Google Workspace Standard — $3.00/inbox
- Google Workspace Pre-Warmed — $4.50/inbox
Explore Our Resources
- Cold Email Blog — 33 guides and articles
- B2B Sales Tools Directory — 159+ tools reviewed
- Provider Comparisons — Head-to-head cold email platform comparisons
- Community Discussions — 113+ threads from cold email practitioners
Latest Blog Posts
- Best Cold Email Infrastructure Providers in 2026 — Honest Comparison — We evaluated the top cold email infrastructure providers on pricing, deliverability, Google Workspace support, and warmup — here's how they stack up.
- Why Your Cold Emails Land in Spam (And How to Fix It) — Your cold emails are landing in spam? Here are the 6 most common infrastructure problems causing it and exactly how to fix each one.
- SMTP vs Google Workspace for Cold Email — Why Infrastructure Type Matters — SMTP providers don't carry the same IP authority as Google Workspace. Learn why infrastructure type is the biggest factor in cold email deliverability.
- How to Set Up SPF, DKIM, and DMARC for Cold Email in 2026 — A complete step-by-step guide to configuring email authentication records that ensure your cold emails reach the inbox, not spam.
- Cold Email Warmup: The Complete 2026 Guide — How to properly warm up cold email inboxes to establish sending reputation without getting suspended. Day-by-day protocol included.
- How Many Cold Email Inboxes Do You Actually Need? — A practical calculator for determining the right number of inboxes based on your email volume, ICP size, and meeting goals.
Popular Tools
- Puzzle Inbox — Google Workspace & Microsoft 365 inbox provider for cold email at scale
- Infraforge — Private cold email infrastructure with dedicated IPs
- Mailforge — Purpose-built cold email infrastructure platform
- Maildoso — Automated cold email infrastructure (SMTP + Google Workspace)
- Inframail — Flat-rate unlimited inbox cold email infrastructure
- Primeforge — Google Workspace and Microsoft 365 for cold email
- CheapInboxes — Budget email hosting for cold outreach
- ColdSire — Cold email infrastructure service
- Email Astra — Pre-warmed Google Workspace accounts
- Endy Inboxes — Automated Google Workspace & Microsoft 365 infrastructure
- Zapmail — Google Workspace mailboxes for high-volume outreach
- MailReef — Cold email infrastructure with pre-warmed servers