How Puzzle Inbox works
Puzzle Inbox is cold email infrastructure built for operators who actually send. We provision real Google Workspace and Microsoft 365 mailboxes, warm them on a live seed list, configure DNS authentication, and hand over the auth credentials ready to plug into Smartlead, Instantly, Lemlist, Saleshandy or any other cold email sending tool.
The infrastructure stack
Every inbox runs on a real tenant — not a shared relay, not an aliased subaccount, not a custom mail-server. Google Workspace inboxes are actual Workspace accounts. Outlook 365 inboxes are real Microsoft 365 tenants. Sending reputation comes from Google's and Microsoft's own IPs and signing keys.
Sending volume
Max 12 cold + 12 warmup emails per inbox per day on Google Workspace (24 total). Max 3 cold + 3 warmup per inbox per day on Outlook 365 (6 total). Scale by adding inboxes, not by pushing per-inbox volume.
Domains
Pre-warmed inboxes run on our own domains. Standard inboxes can use our domains or yours. The ratio is fixed by platform: 3 inboxes per domain on Google Workspace, up to 100 inboxes per domain on Outlook 365.
The 14-day pre-warm
Pre-warmed inboxes spend 14 days sending and receiving conversational replies across a live seed network before shipping. By the time the inbox arrives, Gmail and Outlook treat it as an established sender with a clean reputation.
DNS done for you
SPF, DKIM, and DMARC are configured and verified before delivery.
Integrations on day one
Every inbox ships with the auth credentials your sending platform expects. Compatible with Smartlead, Instantly, Lemlist, Saleshandy, Reply.io, Quickmail, Woodpecker, and any other cold email tool.
Delivery timing
- Standard inboxes: 24-72 hours after payment.
- Pre-Warmed inboxes: 14 days after payment.
- Bulk orders (150+ inboxes): staged delivery, 20% per day for 5 days.
Read the getting-started guide for the exact buying flow, or the our-process page for what happens after you submit the onboarding form.