Upload your first list
Bulk verification starts with a clean input file. The easiest first win is a small CSV or XLSX that contains one clear email column and no extra formatting surprises.
Pick the right first file
Your first file should be small enough that you can inspect the results manually after the run. A list of a few hundred to a few thousand rows is ideal for the first pass.
Use one of these formats:
.csv.xlsx.txtwith one email per line
Avoid exporting from spreadsheets with merged cells, formula-heavy columns, hidden rows, or comments. Flatten the file before upload.
Prepare the email column
Keep one dedicated email column with raw email addresses only.
Before upload:
- Remove blank rows.
- Remove headings duplicated inside the file.
- Trim obvious notes such as
do not contact, commas, or inline comments. - Confirm the delimiter is consistent if you are using CSV.
If SendSure rejects the file, see the support article on CSV rejection in the help center.
Run analysis before full verification
After upload, use the analysis step first. Analysis gives you a low-risk preview of list quality before you spend credits on the full run.
The preview helps you answer:
- how much of the file is obviously invalid
- whether duplicates exist
- whether the list looks unhealthy before you commit
If the file looks wrong at the analysis stage, stop and fix the input before processing.
Start full verification
Once analysis looks correct, start verification and monitor:
- job status
- progress percentage
- final breakdown by status
Large lists can take longer when provider throttling, greylisting, or deeper network checks are involved. That is normal. If a run appears stalled, capture the job ID before contacting support.
Download and use the result
When the job completes, download the output and sort by result class. The first pass most teams make is:
- suppress
invalid - review
risky - decide policy for
unknownandcatch-all - keep
valid
Do not send the entire export back into production unchanged. The value comes from acting on the breakdown.
Next steps
- Read Results and Statuses before you operationalize the output.
- If you need recurring hygiene, continue to Integration Troubleshooting and connect the source system.
- If you are blocked on import issues, open the support widget and include the job ID or filename.