# How to verify your email list before you send > Dead addresses bounce and bounces cost you reputation. Connect a verification service, clean a real list, and see exactly which contacts to keep, remove, or think twice about. - Canonical URL: https://acellesend.com/kb/articles/how-to-verify-your-email-list-before-you-send - Author: Ryan Walsh, Audience & Analytics Editor - Category: List Management — Segments, tags, import/export, double opt-in, verification, hygiene - Content type: tutorial · Difficulty: beginner - Tags: Bounce Handling, Sender Reputation, Inbox Placement, List Cleaning, Email Verification - Published: 2026-06-22 · Last updated: 2026-08-15 - Reading time: 8 min - Publisher: AcelleMail Knowledge Base, https://acellesend.com/kb --- Every list rots. People change jobs, abandon inboxes, or mistype their address at signup — and each dead address you mail is a bounce that chips away at your sender reputation. Email verification checks each address *before* you hit send, so the bounces never happen. This guide walks you through connecting a verification service and cleaning a real list, start to finish. You'll need about ten minutes. ## Before you start - **A verification provider account and its API key.** The platform ships drivers for 16 services — ZeroBounce, Reoon, Emailable, EmailListVerify, myEmailVerifier, Bouncify, NeverBounce, Kickbox, Debounce and more. Most hand out free trial credits, which is plenty to test with. - **A plan that includes email verification.** If you hit *"email verification servers are not included on your current plan"* when saving, that's a plan quota, not a mistake on your side — ask your administrator to enable it. - **A list worth cleaning.** Anything you imported from elsewhere, or haven't mailed in a few months, is a good candidate. - **A queue worker covering the right queues.** Verification runs as a background job, and *which* queue it lands on depends on your provider (see Step 4). A worker started with `--queue=high,batch,default` covers every case. ## Step 1 — Open the Email verification screen In the left sidebar, under **Sending**, click **Email verification**. This is where every verification service you connect will live. ![The Email verification screen under Sending, listing your connected verification services](https://acellesend.com/plugins/acelle/landing/images/kb-bot/how-to-verify-your-email-list-before-you-send/step-1.png) Click **Add server** (top right) to connect your first one. ## Step 2 — Pick your verification service Fill in a **Server name** you'll recognise later, then choose your provider from the **Verification service** dropdown. ![The Add Verification Server form with the Verification service dropdown open](https://acellesend.com/plugins/acelle/landing/images/kb-bot/how-to-verify-your-email-list-before-you-send/step-2.png) Server name, Verification service and Rate Limits are all there from the start. The one block that stays hidden is **API Configuration** — each provider asks for different credentials, so those fields only appear once you've picked a service. ## Step 3 — Paste your API key and set a rate limit Choosing a service reveals the **API Configuration** block. Paste the API key from your provider's dashboard, then fill in **Rate Limits**. ![The completed form: server name, API key, and rate limits of 100 verifications per 1 hour](https://acellesend.com/plugins/acelle/landing/images/kb-bot/how-to-verify-your-email-list-before-you-send/step-3.png) All three rate-limit fields are required, and they're the ones people miss — leave any of them blank and the form quietly refuses to save: - **Max verifications** — how many addresses this server may check per period (100 is a sensible start). - **Per time base** and **Time unit** — the period itself, e.g. `1` + `hour`. Rate limits exist to protect your provider credits. If your provider gives you 20 checks a day, a runaway job on a 50,000-address list would burn through them in seconds. > **The key isn't checked when you save.** The form accepts any string. A wrong or empty key only surfaces when a run actually calls the provider — see Troubleshooting. Click **Add server**. You'll land back on the list of verification servers with your new one on it. ## Step 4 — Open your list and start the run Go to **Audience → Lists**, click the list you want to clean, then open its **Email verification** tab. Under **Verification controls**, pick the server you just created from **Select verification server** and click **Start verification**. ![A list's Email verification tab before a run: 10 total, 0 verified, 10 unverified, with the server selected and Start verification ready](https://acellesend.com/plugins/acelle/landing/images/kb-bot/how-to-verify-your-email-list-before-you-send/step-4.png) The counters at the top tell you where you stand before you spend a credit: how many subscribers the list holds, how many have been checked before, and how many are still unverified. A run only checks the unverified ones. The run happens in the background — you'll see a progress bar climb rather than a frozen page, and you can leave and come back. **Which queue it uses depends on your provider.** Services that support bulk verification — ZeroBounce, Reoon, Emailable, EmailListVerify, myEmailVerifier, Bouncify and NeverBounce — hand the whole list over in one API call and run on the `high` queue. The rest, Kickbox and Debounce among them, check addresses one at a time on the `batch` queue. That's why the worker in *Before you start* covers both. ## Step 5 — Read the results When the bar reaches 100%, **Verification results** breaks your list into four buckets: ![Verification results: 4 deliverable, 3 undeliverable, 3 risky, 0 unknown](https://acellesend.com/plugins/acelle/landing/images/kb-bot/how-to-verify-your-email-list-before-you-send/step-5.png) - **Deliverable** — the mailbox exists and accepts mail. Keep these. - **Undeliverable** — the domain or the mailbox doesn't exist. These are guaranteed bounces. Remove them. - **Risky** — the address resolves, but something's off: a catch-all domain that accepts everything, a disposable address, or a likely typo. Judgement call. - **Unknown** — the provider couldn't get a definitive answer, usually a server that wouldn't respond. Re-check these later. In the run above, ten addresses split 40% deliverable, 30% undeliverable, 30% risky. That undeliverable 30% is exactly what you *didn't* just mail. Need to run the whole list again — after a re-import, or to re-check a batch of Unknowns? **Reset verification data** at the bottom of Verification controls clears every verdict, so the next run treats the list as unverified again. It asks *"Reset all verification data? This cannot be undone."* first, and it does mean spending the credits a second time. ## Step 6 — Act on what you found Open the list's **Subscribers** tab and you'll see the verdict on each address: ![The subscribers list showing a verification verdict against each address](https://acellesend.com/plugins/acelle/landing/images/kb-bot/how-to-verify-your-email-list-before-you-send/step-6.png) To act on a whole bucket at once: set the **verification filter** in the toolbar to **Undeliverable**, tick the checkbox in the table header to select every matching subscriber, then choose an action from the **Select** menu. > **Delete is permanent.** The confirmation says so plainly — *"This will permanently remove the selected subscribers and all their data. This cannot be undone."* If you'd rather keep the record, **Blacklist** stops them being mailed and blocks the address across all your lists. A sane policy for most senders: - **Undeliverable** — remove them. There's no upside to keeping an address that cannot receive mail. - **Risky** — usually worth holding back from your main sends. Disposable addresses will never engage; a catch-all might be fine. If a risky address is an obvious typo like `user@gmial.com`, the person meant `gmail.com` — worth a manual fix. - **Deliverable** — mail with confidence. Re-verify every few months, and always after importing a list from somewhere else. For the wider routine this fits into, see [Email list hygiene: clean your list for better deliverability](https://acellesend.com/kb/articles/email-list-hygiene-clean-your-list-for-better-deliverability). ## Troubleshooting **"Email verification servers are not included on your current plan."** A plan quota, not a form error. Your plan needs email verification enabled before you can add a server. **"Reoon: missing api_key in server options."** Every driver throws this same shape — your provider's name, then the message. It appears when a run starts, not when you save the server, because the key is only read at call time. Reopen the server and re-paste the key, checking for a trailing space. **The run finishes and everything is Unknown.** A key that's present but wrong looks exactly like this: the provider rejects the call and the driver has no verdict to record. Confirm the key in your provider's dashboard, and check you haven't run out of credits, before re-running. **The progress bar sits at 0% and nothing happens.** The job is queued but no worker is consuming that queue. Check which queue your provider uses (Step 4), then start a worker that covers it — `--queue=high,batch,default` covers both paths. **The run slows to a crawl on a big list.** Your rate limit is a run-time throttle, not just a form field. A limit of 100 per hour on a 5,000-address list means the run paces itself over days rather than failing — that's working as intended. Raise the limit only as far as your provider plan actually allows. ## Recap You connected a verification service, cleaned a real list, and turned a pile of unknown addresses into a clear keep / remove / decide split — before a single bounce hit your reputation. The habit that keeps it working: verify after every import, re-verify quiet lists a few times a year, and remove undeliverables the same day you find them. Next, it's worth understanding [what different bounce types actually mean](https://acellesend.com/kb/articles/understanding-email-bounce-types) and [how to monitor your sender reputation](https://acellesend.com/kb/articles/sender-reputation-monitoring) over time. --- ## Related articles - [Importing Contacts CSV — Best Practices and the 6-Click Field Mapping Wizard](https://acellesend.com/kb/articles/importing-contacts-csv-best-practices-and-field-mapping): Format the CSV right before you upload — column headers in row 1, UTF-8 encoding, one email per row. AcelleMail's import wizard handles the rest in 6 clicks. Visual walkthrough of the wizard plus error-recovery patterns + bulk-update strategies in the collapsible section. - [List Hygiene in AcelleMail: Verify, Filter, Blacklist](https://acellesend.com/kb/articles/email-list-hygiene-clean-your-list-for-better-deliverability): AcelleMail gives you three concrete tools to keep a list clean — per-list email verification, the Subscribers status filter, and a customer-managed Blacklist. This walkthrough shows when to use each and what good hygiene looks like in production. - [Subscriber Preferences & Frequency — A Preference Center That Reduces Unsubscribes](https://acellesend.com/kb/articles/managing-subscriber-preferences-and-frequency): Offer a preference center — "Hey, instead of unsubscribing, want fewer emails per week, or only the product updates?" — and unsubscribe rates drop materially. AcelleMail's built-in Update form covers this in 3 clicks. Visual walkthrough plus per-topic-list patterns in the collapsible. - [Segments: Slice Your List Into Audiences That Convert](https://acellesend.com/kb/articles/advanced-segmentation-strategies): Build dynamic subscriber groups in AcelleMail using list fields, tags, activities, and email-verification results. Walk-through with real screenshots of the segment builder. - [Build a Signup Form and Embed It on Your Site](https://acellesend.com/kb/articles/creating-effective-signup-forms-and-landing-pages): AcelleMail has a drag-and-drop visual builder for signup forms with 4 popup layouts and 5 display triggers (immediate, delay, exit intent, on click, first visit). Walkthrough with real screenshots of every panel.