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, 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 generic domains. Standard inboxes run on your own domain — you bring it from GoDaddy, Hostinger, Cloudflare, or any other registrar and we handle the full DNS setup (SPF, DKIM, DMARC). 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. We follow Google's bulk sender requirements at support.google.com/mail/answer/81126 and Microsoft's anti-spam guidelines at learn.microsoft.com.

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

  • Every order ships within 24-72 hours of the onboarding form.
  • Bulk orders (500+ inboxes) may stagger by a day.
  • 2FA on the receiving account can delay handoff. Disable it before delivery.

Read the getting-started guide for the exact buying flow, or the our-process page for what happens after you submit the onboarding form.