Instantly + Puzzle Inbox Integration: Complete Setup Guide

By Ayse Yilmaz, Senior Editor, Cold Email Tools · May 20, 2026 · 6 min read · Last reviewed May 20, 2026

Step-by-step guide to connecting Puzzle Inbox cold email inboxes to Instantly for sending. OAuth setup, configuration, and best practices.

Instantly + Puzzle Inbox Integration

Pre-warmed cold email inboxes from Puzzle Inbox connect to Instantly sending platform via OAuth or SMTP/IMAP. This guide covers the complete integration setup.

Why This Combination Works

  • Puzzle Inbox provides pre-warmed Google Workspace ($3-4.50/inbox) and Outlook 365 ($0.35/inbox) inboxes ready to send
  • Instantly provides advanced sequencing, AI features, and reply management
  • Together: Best deliverability foundation + best sending platform features

Step 1: Order Puzzle Inbox Inboxes

Visit puzzleinbox.com. Choose:

  • Outlook 365 at $0.35/inbox (cheapest pre-warmed)
  • Google Workspace at $3-4.50/inbox (best Gmail deliverability)
  • Mixed for platform diversification

Specify quantity, sending domain preferences, payment via Stripe. Receive credentials in 24-72 hours.

Step 2: Sign Up for Instantly

Visit instantly.ai. Choose plan based on volume:

  • Growth ($30/month): Up to 5,000 emails/month
  • Hypergrowth ($77.60/month): Up to 25,000 emails/month
  • Light Speed ($358/month): Unlimited

Step 3: Connect Puzzle Inbox to Instantly via OAuth

For Google Workspace Inboxes

  1. Instantly → Settings → Email Accounts → Add Account
  2. Click "Add Google Account"
  3. Sign in with Puzzle Inbox-provided credentials
  4. Grant Instantly OAuth permissions
  5. Inbox connected

For Outlook 365 Inboxes

  1. Instantly → Settings → Email Accounts → Add Account
  2. Click "Add Microsoft Account"
  3. Sign in with Puzzle Inbox credentials
  4. Grant OAuth permissions
  5. Inbox connected

Step 4: Configure Sending Limits

Per inbox in Instantly:

  • Daily limit: 15-20 cold emails (recommended)
  • Hourly limit: 3-5 emails
  • Time gap between sends: 30-60 seconds

Pre-warmed inboxes can support immediate full volume — no ramp-up needed.

Step 5: Configure Warmup (Optional)

Puzzle Inbox inboxes arrive pre-warmed. Continuous warmup maintenance is included by Puzzle Inbox provider. You can also enable Instantly's free warmup network for additional reputation reinforcement (recommended for added safety).

Step 6: Test the Integration

Before launching campaigns:

  • Send 5 test emails to your own seed addresses
  • Verify deliverability (primary inbox vs spam)
  • Check email headers for correct authentication
  • Confirm reply forwarding works

Step 7: Launch First Campaign

Create campaign in Instantly using connected Puzzle Inbox accounts. Sends rotate automatically across all connected inboxes.

Step 8: Monitor Performance

Track in Instantly Analytics:

  • Per-inbox reply rate
  • Bounce rate
  • Open rates by inbox
  • Inbox health scores

Pre-warmed Puzzle Inbox accounts typically show 4-5%+ reply rates from day one — significantly higher than self-warmed alternatives.

Cost Breakdown for 30 Inbox Setup

  • Puzzle Inbox 30 Outlook inboxes: $10.50/month (or 30 Google Workspace at $90-135/month)
  • Instantly Hypergrowth: $77.60/month
  • Total: $88-213/month for complete cold email infrastructure + sending platform

Why OAuth vs SMTP/IMAP

For Puzzle Inbox + Instantly integration, OAuth is recommended:

  • More secure (no password storage)
  • More stable connections (don't break on password rotation)
  • Token expiration after 90 days (re-authenticate)
  • Works seamlessly with 2FA on Puzzle Inbox accounts

Common Integration Issues

  • OAuth permissions denied: Verify admin access on Puzzle Inbox account
  • Connection drops: Re-authenticate via OAuth flow
  • Sending failures: Check Instantly sending limits configured correctly
  • Bounce issues: Verify list quality, not infrastructure issue
Instantly + Puzzle Inbox = optimal cold email stack for solo SDRs and small teams. Pre-warmed infrastructure + best-in-class sending platform. Setup takes 30 minutes. Ready to send within 24-72 hours of ordering inboxes.

Related Reading

Related Articles

Related Tool Reviews

  • Puzzle Inbox — Google Workspace & Microsoft 365 inbox provider for cold email at scal
  • SimpleInboxes — Cold email inbox provider with simple per-inbox pricing
  • CheapInboxes — Budget cold email hosting on SMTP-IMAP infrastructure

Ready to start sending?

Puzzle Inbox provisions pre-warmed Google Workspace and Outlook 365 cold email inboxes ready to send within 24-72 hours. See the pricing page, the how-it-works walkthrough, or the our-process page for full details.

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