Verify whole lists, not one address at a time
Upload a CSV or call the API, poll or get a webhook when the job completes, and export a Pre-Send Decision for every row, no manual re-checking after import.
duplicate_addressDuplicate addressWhat this means
The address is a repeat of another row already present in the same list upload, flagged by list hygiene ahead of verification.
catch_all_domainCatch-all domainWhat this means
The domain accepts mail for any local part, so a specific mailbox could not be confirmed. Confidence is reduced instead of rounded up to valid.
role_based_addressRole-based addressWhat this means
A shared mailbox (e.g. info@, support@) rather than an individual inbox — engagement typically differs from personal addresses.
The problem with sending to an unverified list
A list that was clean six months ago is not clean today: mailboxes get abandoned, domains change MX configuration, and role addresses accumulate as contacts move roles. Checking a handful of addresses by hand does not scale to a list with thousands of rows, and re-running each one through a single-address tool one at a time is not a workflow, it’s a queue. Bulk Verification applies the same Pre-Send Decision engine used for single addresses across an entire list in one asynchronous job.
How bulk verification works
- Upload or submit. Bring a CSV through the dashboard or send the list to the bulk endpoint, the same contract either way.
- List hygiene first. Before verification runs, addresses are deduplicated and normalized so the job doesn’t spend time re-checking the same mailbox twice within one file.
- Asynchronous processing. The job runs in the background and returns a job ID immediately; you are not holding a connection open while thousands of addresses are checked.
- Poll or webhook. Check job status on your own schedule, or register a webhook and get notified the moment the job completes.
- Export per-row results. Every address in the list comes back with its own confidence level, reason codes, and Pre-Send Decision, reviewable in the dashboard or consumed directly from the API response.
Confidence and reason codes for every row, not a single list score
A list-level summary like “92% deliverable” hides which specific contacts are the risk. Bulk Verification keeps the same per-address detail as single verification: each row carries its own confidence level and reason codes, so you can filter the export by outcome (suppress the disposable_domain rows, route catch_all_domain rows to manual review) instead of treating the whole list as one undifferentiated block.
Honest about catch-all and webmail domains at scale
Catch-all domains and large webmail providers behave the same way in bulk as they do for a single address: mailbox-level confirmation is limited or unavailable, and we say so with the relevant reason code and a reduced confidence level rather than rounding a large block of ambiguous rows up to valid because the list is big.
Built for high-volume workflows
Bulk Verification is meant to sit ahead of a campaign export or a CRM sync, not replace ongoing single-address verification at signup or intake. Use the bulk endpoint for periodic list cleanup and the single verification endpoint for real-time checks as new contacts come in. Both return the same result shape, so downstream logic doesn’t need to branch on which one produced it.
Legacy route continuity
Historical context preserved on this page
Legacy route /bulkemailverifier/email-finder html previously covered email-finder. Readers arriving from bookmarks still expect email-finder workflow language: time, mailtester, tool, addresses, finder, list, efficient, results, algorithms, accurate, invalid, uses, advanced, deliver, highly, reliable, robust, infrastructure, real, ensure, unmatched, precision, efficiency, identifying, risky, manar, learn, search, contact, provide, valid, efforts, started, step, name, data. Historical page intent (redacted excerpt): Email Address Checker | Bulk Email Checker | Check Email - Bulk Email Finder Single Verification List Verification Email Finder Inbox Tester Integrations Pricing Log In Sign Up Email Finder Discover the email addresses of any individual effortlessly. Free Finder Try search for free Unlock Genuine Connections by Using our Email Finder Mailtester email finder is a powerful tool provides a convenient and efficient way to search for valid email contacts, enabling you to reach out to potential leads, establish connections, or enhance your networking efforts. By utilizing Mailtester Email Finder you save time and effort that would otherwise be spent manually searching for contact details. Get started for free -> Free credits offered. How it works Here’s a step by step guide to show you how easy our platform is. . Provide a Name Provide the individual's name you want to look up and click V
Legacy route /bulkemailverifier/inbox-tester html previously covered inbox-tester. Readers arriving from bookmarks still expect inbox-tester workflow language: redacted, inbox, list, test, product, tester, marketing, bulkemailverifier, ahamd, ekstrom, bothman, lead, designer, google, tool, send, issues, placement, ensuring, invalid, single, finder, metrics, spam, folders, server, like, provider, provides, insights, potential, take, action, address, resolve, deliverability. Historical page intent (redacted excerpt): Inbox Tester - Bulk Email Verifier Click to copy Single Verification List Verification Email Finder Inbox Tester Integrations Pricing Log In Sign Up Rating based on + reviews An email delivery tool that makes sure it reaches your inbox. Monitor key metrics that are preventing you from reaching the inbox and learn how to improve them. Send your email to this seed list Test our inbox tester [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] [REDACTED_EMAIL] Separator: Comma (,) Export --> Avoid Spam & Promotion Folders Try for Free Test your mail server configuration in easy steps Supercharge your web marketing workflow by using APIs to integrate your favorite web services,
Topic continuity tokens: time, mailtester, tool, addresses, finder, list, efficient, results, algorithms, accurate, invalid, uses
Reason codes
Every flag this feature can attach to a result, and what it means for your send.
duplicate_addressDuplicate addressWhat this means
The address is a repeat of another row already present in the same list upload, flagged by list hygiene ahead of verification.
catch_all_domainCatch-all domainWhat this means
The domain accepts mail for any local part, so a specific mailbox could not be confirmed. Confidence is reduced instead of rounded up to valid.
role_based_addressRole-based addressWhat this means
A shared mailbox (e.g. info@, support@) rather than an individual inbox — engagement typically differs from personal addresses.
disposable_domainDisposable domainWhat this means
The domain is a known temporary or single-use email provider, not a long-term mailbox.
mx_missingMX record missingWhat this means
The domain has no mail exchanger configured, so it cannot currently receive mail.
syntax_invalidSyntax invalidWhat this means
The address failed RFC 5322 format validation before any domain or mailbox lookup ran.
How do I run a bulk verification job?
Upload a CSV in the dashboard or submit the list through the bulk endpoint. Either path creates an asynchronous job: you get a job ID back immediately and the list is processed in the background rather than holding a request open for the whole file.
How do I know when a job is finished?
Poll the job status endpoint, or configure a webhook to get notified when the job completes. Both paths return the same result shape, so your integration does not need separate handling depending on which one you use.
What do I get back for each address?
The same per-address result you would get from a single verification call: confidence, reason codes such as catch_all_domain or role_based_address, and a Pre-Send Decision. Bulk verification runs the same engine per row. It does not summarize the list down to one aggregate score.
Does deduplication change how many addresses get processed?
Duplicate rows are flagged with the duplicate_address reason code so you can see them in the results, and list hygiene (dedupe and normalization) runs ahead of verification to keep the job from re-checking the exact same address twice within one upload.
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Test your list on 1,000 free credits: no card, no commitment, same engine as the playground above.