Learn how CSVgo identifies email service providers such as Google, Outlook, and others to enable ESP-based segmentation and improve cold email deliverability and reply rates.
After verification and catch-all analysis, CSVgo identifies the email service provider (ESP) for every deliverable email address.
This step classifies emails into:
Google
Outlook
Other providers
ESP identification happens automatically as part of the same workflow. No external tools are required.
Why Email Service Provider Identification Matters
Email deliverability and reply rates are strongly influenced by the recipient’s email provider.
Different providers:
Filter emails differently
Apply different spam rules
React differently to volume, copy, and sending patterns
Treating all providers the same often leads to:
Lower inbox placement
Reduced reply rates
Burned sender reputation
How CSVgo Identifies ESPs
CSVgo analyzes domain-level and MX-level signals to determine which provider handles incoming mail for each address.
This allows CSVgo to reliably group emails into:
Google-hosted inboxes
Outlook and Microsoft-hosted inboxes
Other providers (custom servers, regional hosts, or legacy setups)
The result is a fully segmented list without manual lookups.
Common Use Cases
ESP-Specific Campaigns
You can run separate campaigns for:
Google-only inboxes
Outlook-only inboxes
Other providers
This allows you to tailor:
Copy
Volume
Warm-up strategy
Sending schedule
Excluding Outlook Temporarily
Many outbound teams choose to:
Delay sending to Outlook inboxes
Exclude Outlook during early warm-up phases
Send to Outlook with lower volume or different infrastructure
CSVgo enables this instantly without additional tooling.
Proven Impact on Reply Rates
Segmenting or excluding certain ESPs has been shown to:
Improve inbox placement
Reduce spam filtering
Increase reply rates by 2–3x or more
Results depend on:
Sending infrastructure
Domain age
Volume
Copy quality
ESP identification gives you the control needed to optimize these variables.
No External Tools Required
Without CSVgo, ESP identification typically requires:
Additional paid tools
Manual domain checks
Spreadsheet work
Multiple exports and imports
CSVgo performs ESP identification automatically as part of the same processing flow.
Summary
In Step 6, CSVgo:
Identifies Google, Outlook, and other email providers
Segments inboxes automatically
Enables ESP-specific outreach strategies
Removes the need for external ESP detection tools
After this step, your list is fully verified, segmented, and ready for analytics and export.