Bulk email validation CSV checklist
A practical checklist for uploading, validating, segmenting, and exporting CSV email lists without damaging sender reputation.
Bulk validationCSVList hygiene
Before upload
- Keep one email column with a clear header such as
email. - Preserve a stable contact ID, CRM ID, or source row ID.
- Remove obvious duplicates before upload if your CRM policy depends on one record per recipient.
- Separate stale, purchased, scraped, and first-party opt-in lists before validation.
After validation
| Segment | Action | Why |
|---|---|---|
| Invalid | Suppress | Hard bounces damage sender reputation. |
| Disposable | Suppress or require review | Temporary inboxes are low-quality for most workflows. |
| Catch-all | Segment | SMTP acceptance does not prove the user exists. |
| Role | Segment | Shared inboxes behave differently from individual recipients. |
| Unknown | Retry later | Provider throttles, greylists, or blocks can be temporary. |
Where WillItInbox fits
WillItInbox supports UI CSV upload and API bulk jobs. For automation, use the API reference. For the broader strategy, read list hygiene and sunsetting.
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