What your email verification results mean

When you verify an email list, WarmySender gives every address two things: a headline status — Valid, Risky, Unknown, or Invalid — and, behind it, a precise detail that says exactly what we found, a confidence score from 0 to 100, and two separate answers to the questions "will this be delivered?" and "should you actually send to it?". This guide explains all of it and tells you exactly what to do next, so you can send confidently and protect your sender reputation. The short version: remove the addresses that don't exist, and send the rest with warmup running on your mailbox. Wondering how many addresses you can check, or why Unknown results never cost you anything? The complete guide to how your verification allowances and credits work covers that side.

WarmySender runs your outreach on autopilot with AI agents, across Cold Email, Email Warmup, LinkedIn, Instagram and Multichannel sequences — plus real-time email verification. An agent connected to your workspace can verify a list for you in plain language, but it never sends a message on its own and can never raise a limit; WarmySender's scheduler paces every send inside safe per-account caps and the warmup ramp no matter who's driving. The Email Verifier is part of Cold Emailing: clean your list before you send so more of your messages reach the inbox.

The four statuses at a glance

The status is the quick answer. The detail below it is the precise one — and it's the column worth sorting on when you want to act on a big list.

The detail behind each result

"Risky" and "Invalid" each cover more than one real-world situation, and treating them all the same would make you throw away addresses worth keeping. So alongside the headline status, every address gets a precise detail — the exact condition we found. You'll see it next to each result in the app and in the detail column of the downloaded CSV.

The detail always fits under the headline status: a Valid address reads as safe or role account; a Risky address reads as catch-all; an Invalid can be plain invalid, or the more specific disabled, inbox full or disposable when we can tell which; and Unknown stays unknown. Because the detail is worked out from what the receiving server already told us, a list you verified months ago picks up this richer detail automatically — no re-check and no extra charge.

Your confidence score (0–100)

Every confirmed result also carries a confidence score from 0 to 100 — a single number for "how sure are we, and how good a contact is this?". It's the easiest way to sort a big list from best to worst at a glance. Higher is better. Here's the range each detail typically falls in:

Two things nudge a score down a little, on purpose:

• Shared inboxes and tagged aliases. A role account (support@, info@) and an alias with a +tag in it are both real and deliverable, but they're weaker signals for a durable business contact, so they score a touch below a plain personal mailbox.
• Microsoft- and Yahoo-hosted domains. When a confirmed mailbox sits on a Microsoft- or Yahoo-hosted domain, we cap the score a little lower — into the high 80s — because those systems' answers are less definitive than others. It's a confidence discount, not a mark against the person.

An Unknown result has no score at all — the box is left blank rather than shown as 0. A 0 would read as "definitely bad", and Unknown is the opposite: it's the absence of a verdict, not a low one. (It's also free.)

Deliverable vs. safe to send — two different questions

Alongside the detail and score, each result answers two questions that sound alike but aren't:

• Deliverable — will the receiving server physically accept the mail?
• Safe to send — should you actually send to it?

They're kept separate on purpose, because the clearest example is a catch-all address: it's deliverable (the server accepts everything) but not safe to send in the confident sense, because we couldn't confirm that this specific mailbox is real. A role account is the reverse kind of nuance — it's both deliverable and safe to send (the mail reaches a real, monitored inbox); the fact that a shared inbox converts worse on cold outreach shows up in the lower score, not by flagging a working address as unsafe. Collapsing these two questions into one is exactly what makes a plain "risky" label so unhelpful — so we don't.

Valid — safe to send

A Valid result means we confirmed the mailbox exists and is able to receive email. These are your safest addresses, and they're the ones to send to first. Within Valid, the detail tells you whether it's a safe personal mailbox or a role account (a shared inbox like support@ or info@) — both are sendable, but named individuals usually respond better than shared inboxes. Verifying a list before you send keeps your bounce rate low, which is one of the biggest factors in whether your future emails land in the inbox.

Even with Valid addresses, sending through a mailbox that has warmup running is the best way to keep your reputation strong as your volume grows.

Some results are confirmed by real delivery

Most verification tools can only ask a receiving mail server whether an address looks real. WarmySender can sometimes do better: when your own campaigns have already delivered mail to an address, we know that inbox is real and reachable — because a message actually landed there. That's first-hand proof, stronger than any live check.

When a result is backed by that real delivery history, you'll see a small “Real delivery” note next to it in your results (and in the CSV's evidence column). It's a sign you can send with extra confidence: this isn't a best guess, it's an address your mail has reached before.

Risky — catch-all

A Risky result means a catch-all domain — a company whose mail server is set to accept mail for every address, whether or not that specific mailbox exists. That's a setting on the receiving end, not a problem with your list: because the server says yes to everything, no tool can single out whether this exact person's mailbox is real, even though the domain itself is live. (Its detail reads catch-all, it's marked deliverable but not confirmable, and it scores around 75.)

Because of that, many Risky addresses are perfectly deliverable — they simply can't be confirmed one at a time. The safe way to reach them is to send gradually with warmup enabled on your sending mailbox, so that if a few don't land, your sender reputation stays protected. For an important list, you can also re-check Risky addresses later. There's a deeper explanation of catch-all domains and how to decide whether to email them in our glossary entry on catch-all (accept-all) domains.

Unknown — we couldn't confirm either way (and it's free)

This is the result people ask about most, so here it is plainly: Unknown means we couldn't confirm the address either way — it does not mean the address is bad. Some receiving mail systems, especially large, security-conscious businesses and Microsoft-protected domains, deliberately refuse to reveal whether any given mailbox exists. When a receiving system keeps its answer private like that, the honest result is Unknown rather than a guessed Valid or a false Invalid.

Two things make Unknown easy to work with:

• It's free — always. An Unknown result never uses a credit and never counts toward a monthly allowance, whichever route you're verifying on: the free daily check, purchased credits, or a plan's included allowance. You're only ever charged for a result we could actually confirm. That's also why an Unknown result carries no confidence score — there's no verdict to score.
• It's usually safe to email. Many Unknown addresses are real and reachable; the receiving system simply wouldn't say so. Send them with warmup running on your mailbox and your reputation stays protected.

Yahoo and AOL addresses. They come back as Unknown. Yahoo's mail system, which also runs mail for AOL, Ymail, Rocketmail, sbcglobal.net, att.net, bellsouth.net, pacbell.net, verizon.net and some company domains, says yes to every address it's asked about. No checker can confirm that a particular mailbox exists, and dead Yahoo and AOL mailboxes bounce far more often than confirmed ones when you send. So these addresses are not charged and are not in your "Verified" list. If they matter to you, send to them in small batches from a separate campaign and watch your bounces, or leave them out.

We made this choice on purpose: we'd rather tell you we couldn't confirm an address than label a genuine, reachable prospect as bad and have you skip them.

Invalid — the address doesn't exist

An Invalid result means the address itself doesn't exist or can't receive mail — for example, a typo, a mailbox that was closed, or a domain that no longer accepts email. You should skip Invalid addresses entirely. Where we can tell precisely why, the detail says so: disabled means a mailbox that existed and was switched off (someone who left the company); disposable means a throwaway/temporary-inbox provider. One Invalid-adjacent detail is worth keeping rather than skipping — inbox full, which means the mailbox exists but is over quota right now, so it's likely reachable again later.

Removing Invalid addresses before you send is the single most valuable thing verification does for you. Sending to addresses that don't exist is what drives up your bounce rate and damages your sender reputation — exactly the harm that cleaning your list first is meant to prevent.

How to send based on your results

A simple, reputation-first way to act on a verified list:

• Send Valid first, highest scores first. Start with your confirmed Valid addresses — and if you're pacing a big list, sort by the confidence score and lead with the safe, high-scoring personal mailboxes.
• Send Unknown and Risky with warmup enabled. These are usually fine to email — just make sure warmup is running on the mailbox you send from, so your sender reputation stays protected if a few don't land. (See how to control your warmup sending volume.)
• Skip disabled, disposable and invalid. These won't reach a real, active person, so leave them out.
• Keep "inbox full" for later. That mailbox exists — it's just over quota today. Don't delete it.
• Re-check borderline results for high-stakes lists. For your most important outreach, it's worth re-checking borderline Unknown or Risky addresses before you send — receiving systems can answer differently at different times, so a fresh check sometimes resolves to a clearer result.
• Re-verify older lists before you reuse them. Email addresses go stale — people change jobs and close mailboxes over time. If a list has been sitting for a month or more, run it through the verifier again before your next send (why a verified list can still bounce).

Using your verified results in a campaign

Once a verification finishes, you don't have to sort the results by hand or download and re-upload a spreadsheet — and you don't have to worry about your existing lists or campaigns being changed. WarmySender turns your results into a clean list you can launch a campaign to in one click, and it never edits your original list or touches your existing campaigns, so nothing is duplicated and no one is contacted twice.

• A clean list of the good addresses, ready for a campaign. The Valid and Risky addresses — the ones that are good to email — are gathered into a brand-new list named after your original with “- Verified” on the end. It's a separate list you can point a campaign straight at, so you can send to just the good addresses in one click.
• Uploaded a CSV? Just click “Create clean list”. Verifying a CSV you uploaded works exactly the same way — when it finishes, a Create clean list button builds the very same ready-to-use list of Valid and Risky addresses. So a one-off spreadsheet becomes a campaign-ready audience with a single click. You do not need to download the results and re-upload a trimmed CSV; existing contacts are reused automatically, so there are never any duplicates.
• Your original list and campaigns are left exactly as they were. The verified list is created alongside your original — nothing is moved, merged, or overwritten, and no existing campaign is changed. Because the good addresses are a fresh list rather than an edit to something already sending, there's no risk of duplicating anyone or emailing a contact twice. Anyone already in your account is reused rather than added again, and addresses that came back Invalid are quietly kept out of sending so your campaigns skip them.
• You can also download the full results as a CSV. Prefer a spreadsheet, or want to import elsewhere? Every finished list has a Download option that gives you a CSV of every address with its status, its detail, its confidence score, whether it's deliverable and safe to send, and how we established the result. Use the ready-made verified list for a one-click campaign, or the CSV to handle the results yourself — whichever suits you.

Frequently asked questions

What does an "Unknown" verification result mean?

Unknown means we couldn't confirm the address either way — not that it's bad. Some receiving mail systems, especially heavily protected business and Microsoft-protected domains, won't reveal whether a specific mailbox exists, so we can't return a definite yes or no. An Unknown result is free (it doesn't count toward your monthly verification limit) and carries no confidence score, because there's no verdict to score. These addresses are usually safe to email as long as warmup is running on your sending mailbox — many Unknown addresses are perfectly real; the receiving system simply kept its answer private.

Why are my Yahoo and AOL addresses unknown?

Yahoo's mail system, which also runs AOL, Ymail, Rocketmail and several internet providers such as sbcglobal.net, att.net, bellsouth.net, pacbell.net and verizon.net, says yes to every address it's asked about. That means no checker can confirm whether a particular mailbox exists, so we mark these addresses Unknown. They are not charged and are not in your "Verified" list, because dead Yahoo and AOL mailboxes bounce far more often than confirmed ones. If they matter to you, send to them in small batches from a separate campaign and watch your bounces, or leave them out.

What is the "detail" next to my result, and how is it different from the status?

The status is the headline word — Valid, Risky, Unknown or Invalid. The detail is the precise condition behind it, and it's the column worth sorting on. Valid splits into safe (a confirmed personal mailbox) or role account (a shared inbox like support@ or info@). Risky always means catch-all (the domain accepts every address). Invalid can be plain invalid (no such mailbox), or the more specific disabled (a mailbox that was switched off), inbox full (exists but over quota right now — keep it), or disposable (a throwaway inbox provider). Unknown stays unknown. The detail is worked out from what the receiving server already told us, so even a list verified months ago shows it with no re-check and no extra charge.

What is the confidence score, and why is it blank for some addresses?

The confidence score is a single 0–100 number for how sure we are and how good a contact the address is — higher is better, so it's the easiest way to sort a list from best to worst. A confirmed personal mailbox scores in the high 90s; a shared inbox or a tagged alias a little lower; a catch-all around 75; a throwaway or over-quota mailbox much lower; a non-existent one at the bottom. A confirmed mailbox on a Microsoft- or Yahoo-hosted domain is capped a little lower (into the high 80s), because those systems' answers are less definitive. Unknown results have no score at all — the box is left blank rather than shown as 0, because Unknown is the absence of a verdict, not a bad one.

What's the difference between "deliverable" and "safe to send"?

Deliverable asks whether the receiving server will physically accept the mail. Safe to send asks whether you should actually send to it. They're usually the same, but not always — a catch-all address is deliverable (the server accepts everything) yet not safe to send in the confident sense, because we couldn't confirm that this exact mailbox is real. Keeping the two apart lets you make a smarter call than a single "risky" label ever could: you can still choose to email deliverable-but-unconfirmed addresses, just carefully and with warmup on.

What is a "role account" result, and should I email it?

A role account is a shared or functional mailbox — support@, info@, sales@, hello@ and the like — rather than a named person. It's a valid, deliverable address: real mail arrives. But it lands in a team inbox, so cold outreach to it typically converts worse and is more likely to be marked as spam, which is why it scores a little below a personal mailbox. You can email role accounts, but where you have a choice, a named individual usually gets a better response.

What's the difference between Risky and Invalid?

Risky means a catch-all domain — one set up to accept mail for any address — so we can't single out whether that specific mailbox exists, even though the domain is live. Risky addresses are often fine to email with warmup on. Invalid means the address itself doesn't exist or can't receive mail, so you should skip it; sending to Invalid addresses is the main thing that hurts your sender reputation, which is exactly what verification helps you avoid. Two Invalid details are worth treating differently: inbox full means the mailbox exists but is over quota (keep it for later), while disabled and disposable should be skipped like any other Invalid.

Why are some of my results Unknown when other tools say the address is valid?

Different checks ask the receiving mail system in different ways and at different moments, and some receiving systems — particularly large, security-conscious and Microsoft-protected domains — deliberately give the same neutral answer to everyone. When that happens, the honest result is Unknown rather than a guessed Valid or a false Invalid. We'd rather tell you we couldn't confirm than label a real, reachable address as bad. Unknown results are free and are usually safe to email with warmup on.

What should I do with each result?

Send your Valid addresses first — they're confirmed and safe, and if you're pacing a big list, lead with the highest confidence scores. Send Unknown and Risky addresses too, but with warmup enabled on your sending mailbox so your reputation stays protected. Skip anything whose detail is invalid, disabled or disposable. Keep inbox full for a later attempt — that mailbox exists, it's just over quota today. For high-stakes outreach, re-check borderline Unknown or Risky results before you send, as receiving systems can answer differently over time.

How do I use my verified emails in a campaign?

You don't have to download and re-upload anything. When a verification finishes, WarmySender gathers the Valid and Risky addresses (the ones that are good to email) into a new, ready-to-use list named after your original with “- Verified” on the end — and you point a fresh campaign straight at that list in one click. This works whether you verified an existing list or a CSV you uploaded: for a CSV upload, a Create clean list button builds the very same campaign-ready list. Your original list and existing campaigns are never edited, anyone already in your account is reused (so there are no duplicates and no one is contacted twice), and addresses that came back Invalid are kept out of sending. Prefer a spreadsheet? Every finished list also has a Download option that gives you a CSV of every address, its status, its detail, its confidence score, and whether it's deliverable and safe to send.

Do verified results update my existing lists and campaigns automatically, or do I re-upload the CSV?

Neither is forced on you — you get both options, and your existing lists and campaigns are never edited behind your back. When a verification finishes, WarmySender automatically gathers the Valid and Risky addresses (the ones that are good to email) into a new, ready-to-use list named after your original with “- Verified” on the end. That new list sits alongside your original — nothing is moved, merged, or overwritten, and no existing campaign is changed — so you can point a fresh campaign at just the good addresses with no risk of duplicating anyone or emailing a contact twice. This applies to CSV uploads too: after a CSV finishes verifying, a Create clean list button builds the same ready-to-use list, so you never have to download the results and re-upload a trimmed spreadsheet. (Addresses that came back Invalid are quietly marked so your campaigns skip them, and existing contacts are reused rather than duplicated.) If you'd rather work in a spreadsheet, every finished list also has a Download option that gives you a CSV of every address and its result. Use the ready-made verified list for a one-click campaign, or the CSV to handle the results yourself — whichever you prefer.

Where this page fits in the email verification guide

This page covers one specific thing: what each result means and what to do with it. The rest of the guide covers how much you can verify and what it costs:

• The complete guide to email verification limits & credits — the overview page for your monthly allowance and its daily pace, how to see what's left, and why Unknown results are free
• Using the email verifier without a plan — the free daily check with no sign-up, buying credits with no subscription, and exactly what is and isn’t charged
• Buying verification credit packs that never expire — the one-time packs, their prices, how to buy them, and when a pack beats upgrading your plan
• Monthly allowance vs. credit packs: verifying a big list all at once — how to choose between the two when you need a large list cleaned today

Related reading

• Do I need to verify my list before I send? — When verification is worth it, and what a clean list protects
• Why do verified emails still bounce? — Why a result reflects the moment it was checked, not forever
• Catch-all (accept-all) domains — What a catch-all really is and how to decide whether to email one
• How to control your warmup sending volume — Set the daily volume and ramp so you can send Unknown and Risky addresses safely
• Deliverability resources — How clean lists, warmup, and authentication keep you in the inbox
• Full documentation — Cold Email, Email Warmup, LinkedIn, Instagram and Multichannel guides