Instantly + Puzzle Inbox Integration: Complete Setup Guide

By Puzzle Inbox Team · May 20, 2026 · 6 min read

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