How to verify a CSV email list

From the dashboard: Verify → upload CSV or Excel (or paste). From the API: POST /api/v1/verify/bulk, /verify/bulk/paste, or /verify/bulk/upload with a Bearer key.

Watch the job until it completes. Then download an export. Prefer Valid only for cold send, or Valid + all catch-alls (use with caution) if you explicitly want that reach.

Limits worth knowing

Sandbox bulk is capped at 100 addresses and does not run live SMTP. Live jobs have plan-level parallel bulk limits. Unknown rows are refunded.

More on the job itself: bulk email verification.

Reading the score columns in your export

The full export includes several numeric-looking columns that are not interchangeable. score, confidence_pct, and deliverability_score are ranking heuristics — higher is better, but none of them is a percent chance of deliverability. calibrated_probability is different: it is only populated once we have enough real delivery-feedback data for that pattern, and it is the one figure meant to be read as an actual probability. If a row has no calibrated_probability value, we simply do not have enough evidence yet — that is not the same as zero.