What is an ESP?
An ESP (Email Service Provider) is a platform or service that manages email delivery, including sending, tracking, and optimization. ESPs range from personal email providers (Gmail, Outlook) to dedicated marketing platforms (Mailchimp, SendGrid).
ESP Categories:
| Category | Examples | Best For |
|---|---|---|
| Personal Email | Gmail, Outlook | Cold email, 1:1 sales |
| Marketing ESP | Mailchimp, Constant Contact | Newsletters, bulk email |
| Sales Engagement | Outreach, Salesloft | Sales sequences, CRM integration |
| Transactional | SendGrid, Mailgun | Automated, system emails |
| Cold Email Tools | Instantly, Lemlist | Cold outreach at scale |
Cold Email Reality: For cold outreach, native email providers (Gmail/Outlook) are preferred over marketing ESPs.
Why Your ESP Choice Matters
Your ESP directly impacts deliverability. Marketing ESPs like Mailchimp are shared platforms with reputation baggage—your emails can be hurt by other senders' actions.
ESP Impact:
- Deliverability: Platform choice affects inbox placement
- Warmup Requirements: New ESPs require domain warmup
- Reputation: Shared platforms = shared reputation risk
- Features: Different tools for different use cases
- Cost: Pricing varies dramatically by use case
- Scalability: Some platforms handle volume better than others
Benchmarks
| ESP Type | 2024 Inbox Placement | 2025 Placement | Change |
|---|---|---|---|
| Gmail/Outlook (Native) | ~90% | ~85% | -5% |
| Dedicated Cold Tools | ~85% | ~70% | -15% |
| Marketing ESPs | ~80% | ~53% | -27% |
| Transactional ESPs | ~85% | ~65% | -20% |
Cold Email Recommendation: Gmail and Outlook are preferred for cold outreach because:
- Higher inbox placement
- No shared reputation risk
- More personal appearance
- Better engagement from recipients
Best Practices
- Use Gmail/Outlook for Cold: Native providers perform best
- Dedicate Domains: Separate domains for different purposes
- Avoid Shared ESPs for Cold: Mailchimp prohibits cold email anyway
- Warm Up New Accounts: Always warmup before sending at scale
- Monitor Placement: Test where emails actually land
- Use Multiple Accounts: Scale across multiple inboxes
- Track by Provider: Gmail vs. Outlook performance may differ
- Stay Current: ESP performance changes—benchmark regularly
Common Mistakes
- Using marketing ESPs (Mailchimp) for cold email (prohibited, poor results)
- Not warming up new ESP accounts
- Choosing ESP based on price only (deliverability matters more)
- Ignoring inbox placement differences between ESPs
- Sending too many emails from single ESP account
- Not monitoring ESP deliverability over time
- Using one ESP for all email types (should separate)
- Not having backup ESP accounts ready
Key Takeaways
- ESP choice directly impacts deliverability
- Gmail and Outlook are preferred for cold email
- Marketing ESPs (Mailchimp) have poor deliverability for cold outreach
- ESP inbox placement declined 15-27% from 2024 to 2025
- Native providers avoid shared reputation risks
- Always warm up new ESP accounts before heavy sending
- Use dedicated domains for different purposes
- Monitor ESP performance—benchmarks change over time
Sources:
Related Terms
Economic Buyer
Person controlling budget and making final purchase decision.
Elevator Pitch
30-second summary of value proposition. Clear, compelling, memorable.
Email Authentication
SPF, DKIM, DMARC setup proving you're legitimate sender. Non-negotiable.
Email Automation
Software sending personalized emails based on rules and triggers.
