What's the best workflow for verifying a list before a campaign with Valid Email Checker?

A pre-campaign verification run is the single highest-ROI thing you can do for an email send. Most teams treat it as an afterthought and pay for it in bounce rates and inbox placement. The Valid Email Checker workflow below works for a list of any size from 500 subscribers to a million.

Step 1: export from your ESP

Pull the segment you intend to mail. Export to CSV with at minimum an email column. Other columns are fine and will pass through to your results download unchanged. If your ESP doesn't expose a clean export, use one of our native integrations which pulls the list directly without manual CSV juggling.

Step 2: deduplicate inside VEC, not before

Bulk upload runs an automatic dedupe pass by default (toggle is on the upload page). Leave it enabled. You pay for unique addresses only. Pre-deduplicating in Excel is a waste of time. See how to avoid wasting credits on duplicates for the underlying mechanics.

Step 3: upload and wait

Drag the CSV onto the Bulk Upload page or paste addresses directly. The free 200 welcome credits handle test lists up to 200 addresses. Beyond that, your purchased balance does the work. Processing speed sits around 10,000 to 50,000 addresses per hour depending on load and the kinds of domains in your list.

Step 4: download and segment by status

Once the job finishes, download the results CSV. Each row gets a status: safe, risky, invalid, unknown, catch_all, disposable, role, spamtrap, disabled, or inbox_full. The segmentation rules I'd run by default:

• Send to: safe rows.
• Drop entirely: invalid, disabled, spamtrap, disposable.
• Decide by campaign type: catch_all, risky, role, inbox_full — see should I drop or keep catch-all results and drop or keep role-based addresses.
• Refunded automatically: unknown — no credit charged, retry later.

Step 5: import the clean segment back to your ESP

Filter the results CSV down to your send-to segment and import it as a fresh list or tag the existing list with a vec_verified_at field. Most teams keep a rolling 30-day or 60-day verification window before requiring a re-check. The cadence depends on your acquisition volume.

For ongoing list maintenance (rather than one-off campaigns), see how often to re-verify a list maintained with the VEC API.