Email · Available on All tiers

Clean the whole list before the campaign, not after the bounce report.

Upload a CSV, watch the job progress in real time, and get the same file back with a verdict column appended to every row — up to 100,000 addresses at once on Team.

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Why it matters

Bulk email list cleaning

A list that's been sitting in a CRM for two years is not the list you built it as. People change jobs, domains expire, mailboxes fill up and get abandoned. Send to it anyway and your bounce rate climbs, your sender reputation takes the hit, and your ESP starts asking questions. Cleaning it after the campaign is the wrong order of operations — the damage is already done by then. Picture sending a re-engagement campaign to 20,000 contacts collected over three years: a meaningful chunk of those addresses belonged to people who've since left their jobs, and their old company mailboxes are either dead or forwarding straight to a spam trap. A bounce rate that climbs past what your ESP considers healthy doesn't just fail that one campaign — it can throttle or flag your sending domain for every campaign afterward, turning a stale list into a problem that outlives the send that exposed it. It's the list-hygiene equivalent of checking the milk before pouring it, not after the first sip. A cleaner list isn't just about avoiding bounces — it's about not paying to send mail nobody was ever going to receive.

Watch it happen, not just the result

A live progress page tracks the job as it runs, and it can be cancelled at any point — whatever was still pending gets refunded immediately rather than left to finish unwatched. That matters most on a genuinely large list, where realizing halfway through that you uploaded the wrong file, or an outdated version of it, would otherwise mean either waiting out a job you already know is wrong or losing the credits for everything still queued. It's a small amount of visibility that makes a genuinely large job feel far less like a black box. It's built for the reality that mistakes happen, not just the ideal case where they don't.

Greylisting handled, not misreported

A mailbox that stalls a connection with a temporary 4xx gets retried automatically — up to three times over 30 minutes — before it is ever called a permanent failure. Greylisting is a legitimate, common anti-spam technique mail servers use, not a sign the address is bad — a tool that doesn't account for it would misreport a perfectly good address as invalid just because the first attempt happened to arrive during the temporary delay window. It's the kind of nuance that separates a verification tool built to be accurate from one built to be fast. It's the kind of accuracy that only shows up when you actually look for it.

Your file back, just annotated

Download the exact CSV you uploaded with verdict columns appended next to your own — no reformatting, no separate 'results' file to reconcile against the original. That means the row order, your own custom columns, and any metadata you'd already attached to each contact all stay exactly where they were — verification adds information to your file instead of replacing it with a different one you'd have to merge back in by hand. It's designed to slot into whatever workflow already consumes that CSV, without asking you to change anything about it. It's meant to fit into an existing process, not force a new one.

FAQ

Bulk email list cleaning, answered.

How big a list can I upload?

100 addresses on Free, 10,000 on Starter, and 100,000 on Team, with 1, 2 and 5 jobs able to run at once respectively. Every result comes back in a paginated table and as a downloadable annotated CSV. Running more than one job concurrently is useful if you're cleaning several distinct lists — say, one per campaign or region — without waiting for an earlier job to finish first. That tier-based concurrency scales the same way your list sizes do, so bigger plans aren't just bigger limits — they're faster workflows too. It's sized to match how lists actually grow as a business does.

What happens to a greylisted address?

It's retried automatically at 5, 15 and 30 minutes before being reported as terminal — greylisting is a real, temporary mail-server behavior, not a bounce, and treating it as one would misclassify perfectly good addresses. Only after all three retries fail to get a definitive answer does the address get a final verdict, so a mailbox that just needed a few extra minutes never gets lumped in with addresses that are genuinely dead. It's a small amount of patience that prevents a real mailbox from being wrongly written off. It's a distinction that matters more the larger and more varied a list gets.

Can I download the results while the job is still running?

The live progress page shows counts as the job runs, but the full annotated CSV becomes available once verification finishes — or the moment you cancel it, at which point everything completed up to that point is ready to download immediately, with pending rows refunded rather than left half-processed. Either way, nothing is left in limbo — the file and the credit balance both reflect exactly what happened. It's built so a mistake mid-upload never turns into wasted spend.

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