Cold Email Provider Evaluation Checklist: 15-Point Due Diligence 2026
By Mert Ozdemir, Head of Deliverability · May 14, 2026 · 8 min read · Last reviewed May 14, 2026
Cold email provider evaluation checklist with 15 specific due diligence points. Use this before committing to any cold email infrastructure provider.
The 15-Point Cold Email Provider Evaluation Checklist
Cold email infrastructure provider selection is a high-stakes decision. Bad provider choices cost pipeline, operational time, and migration overhead. Use this 15-point checklist to evaluate any cold email provider before committing.
Infrastructure Authenticity (Points 1-4)
- Real GWS or MS365? Request admin console access. Real accounts give admin.google.com or admin.microsoft.com.
- Dedicated or shared? Ask about infrastructure isolation from other customers.
- Pre-warming included? Verify warmup is actually included, not marketing claim.
- DNS authentication? SPF, DKIM, DMARC correctly configured on delivery.
Pricing Transparency (Points 5-7)
- Per-inbox all-in cost? Include warmup, support, replacement churn.
- Bulk pricing structure? Volume discounts documented.
- Cancellation and refund policy? Written terms available.
Operational Capability (Points 8-11)
- Support speed? WhatsApp/chat response times documented.
- Provisioning time? Hours from order to ready-to-send.
- Account replacement? Policy for suspended inboxes.
- Scale capacity? Can they deliver 100+ inboxes if you grow?
Deliverability Evidence (Points 12-13)
- Published deliverability data? Or willingness to share benchmarks.
- Independent reviews? G2, Capterra, Reddit presence.
Platform Coverage (Points 14-15)
- Google Workspace option? Authentic GWS available.
- Microsoft 365 option? Authentic MS365 available for diversification.
Scoring Framework
- 13-15 points: Excellent provider fit
- 10-12 points: Acceptable with specific considerations
- 7-9 points: Risky choice, evaluate alternatives
- Under 7 points: Do not proceed
Providers That Score High
Puzzle Inbox (15 points): Authentic GWS + MS365, pre-warming included, WhatsApp support, fast provisioning, dual-platform, independent reviews, replacement policy.
Mission Inbox (14 points): Enterprise features, SLAs, comprehensive documentation.
InboxKit (13 points): Google Cloud partner, authentic infrastructure, Azure option for enterprise.
Providers That Score Lower
AI-branded providers (6-8 points): Fail on deliverability data publishing and pricing transparency.
Budget shared infrastructure providers (5-8 points): Fail on dedicated infrastructure, pre-warming, and deliverability evidence.
Related Reading
- The 15-Point Cold Email Deliverability Audit: Run This Before Every Campaign
- Cold Email Deliverability Audit: The 14-Point Checklist
- Cold Email Infrastructure Checklist: Everything You Need Before Sending Your First Email
- Cold Email Inbox Providers for Agencies: Complete 2026 Buyer's Guide
Related Articles
- Best Cold Email Infrastructure Providers in 2026 — Honest Comparison
- Why Your Cold Emails Land in Spam (And How to Fix It)
- SMTP vs Google Workspace for Cold Email — Why Infrastructure Type Matters
- Cold Email Warmup: The Complete 2026 Guide
Related Tool Reviews
- ColdSire — Cold email infrastructure service
- Email Astra — Pre-warmed Google Workspace accounts
- Emailchaser — Bundled inbox infrastructure and lead data platform
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.