Accurate, fast and secure email verification service
We help you find valid emails and connect with customers. Our 99.6% accurate real-time email validation and deliverability tools boost your inbox placement and open rates.
Live email validator
Check an email address in real time
We run syntax checks, suppression checks, disposable detection, MX lookup, and an optional SMTP probe against the mailbox — the same pipeline we use before sending from SendTrim.
Create a workspace for bulk list cleaning
Try a valid mailbox (like your work email) and then an obviously fake one (for example nope+invalid@yourdomain.com) to see how the email validation status and SMTP rejection behave.
Clean your email lists before you hit send
Every bad email address you send to increases your bounce rate and puts more pressure on your sending domain. A few here and there might not sound like much, but at scale they're exactly what inbox providers use to decide whether your next campaign lands in the inbox, the Promotions tab, or spam.
With SendTrim, you can run free real-time checks on single addresses and then upgrade to bulk list cleaning when you're ready. The same pipeline that powers this live validator is used behind the scenes for campaign sending and transactional email: syntax checks, suppression list checks, disposable detection, MX records, and an optional SMTP probe.
Use this tool to verify new signups, leads from forms, CRM exports, or addresses collected in-store. Clean lists mean fewer bounces, fewer spam complaints, and more consistent inbox placement over time.
When to run email validation
- Before importing an old list from another provider (Mailchimp, SendGrid, etc.).
- When you collect leads from events, partners, or scraped sources you don't fully trust.
- As a guardrail on your signup form to block obvious typos and throwaway inboxes.
- Before ramping up volume on a new sending domain or IP.
Bulk list cleaning with SendTrim
Create a free workspace to upload CSVs, validate in bulk, and sync safe contacts back into your segments. Start with up to 15k free validations on the starter tier.
Get started – free up to 15k validationsHow SendTrim email validation works
Syntax check
Validates the email format against RFC standards. Catches typos like missing @ signs, double dots, and invalid characters before anything hits the network.
Domain & MX lookup
Checks that the domain exists, has valid MX records, and is configured to receive email. Filters out defunct domains and parked pages.
Disposable detection
Cross-references the domain against a constantly updated database of disposable and temporary email providers like Guerrilla Mail, Tempmail, and 10MinuteMail.
SMTP probe
Connects to the mail server and checks whether the specific mailbox exists — without sending an actual email. The most reliable way to confirm deliverability.
Why email validation matters for deliverability
Inbox providers like Gmail, Outlook, and Yahoo track your bounce rate closely. When more than 2–3% of your emails bounce, your sender reputation takes a hit. Keep bouncing and your domain gets flagged — even legitimate emails start landing in spam.
Email validation is the simplest way to prevent this. By removing invalid, disposable, and risky addresses before you send, you keep your bounce rate near zero and protect the domain reputation you've worked to build. It's especially critical when:
- You're migrating lists from another ESP and don't know how stale the data is
- You collect leads from landing pages, webinars, or third-party sources
- You're warming up a new sending domain and can't afford early bounces
- Your open rates or click rates have been declining over recent campaigns
Think of validation as insurance for your email infrastructure. A few seconds per address now saves weeks of reputation recovery later.
Types of invalid email addresses we catch
Hard bounces
Mailboxes that don't exist — typos, deleted accounts, or completely made-up addresses. These are permanent failures and should never be sent to.
Disposable addresses
Temporary inboxes from services like Guerrilla Mail or Tempmail. People use these to grab a freebie and disappear — they'll never engage with your emails.
Role-based addresses
Addresses like info@, admin@, or sales@ that go to a group inbox. They typically have low engagement and higher complaint rates.
Catch-all domains
Servers configured to accept mail for any address at the domain. SMTP probes can't tell if the specific mailbox is real — we flag these so you can decide.
Syntax errors
Missing @ symbols, spaces, double dots, and other formatting mistakes. Often from manual entry or sloppy form submissions.
Dead domains
Domains with no MX records, expired registration, or DNS that doesn't resolve. Sending to these is a guaranteed hard bounce.
SendTrim vs other email validators
| Feature | SendTrim | ZeroBounce | NeverBounce |
|---|---|---|---|
| Free tier | 15,000 checks | 100 checks | 1,000 checks |
| SMTP probe | Included | Included | Included |
| Disposable detection | Included | Included | Included |
| Built-in email sending | Yes | No | No |
| Campaign + validation in one tool | Yes | No | No |
| Accuracy | 99.6% | 98% | 97% |
Most validators only validate. SendTrim validates and sends — so your clean list goes straight into campaigns without exporting, importing, or switching tools.
Frequently asked questions
Is the email validator really free?
Yes. You can validate individual emails on this page with no account required. For bulk CSV validation, create a free SendTrim account and get up to 15,000 validations on the starter tier.
Does validation send an email to the address?
No. Our SMTP probe connects to the recipient's mail server and checks whether the mailbox exists, but it never sends an actual message. The address owner won't know you checked.
How accurate is it?
Our validation pipeline achieves 99.6% accuracy across syntax, DNS, disposable detection, and SMTP probing. Catch-all domains are the main edge case — we flag them explicitly so you can make an informed decision.
Can I validate a whole list at once?
Yes. Upload a CSV in your SendTrim dashboard and we'll validate every address in bulk. Results are available for download or can be synced directly into your contact groups for immediate campaign use.
What happens to catch-all addresses?
Catch-all domains accept mail for any address, so SMTP probing can't confirm whether a specific mailbox is real. We label these as "catch-all" so you can choose to include or exclude them from your sends.
Ready to clean your list?
Create a free SendTrim account to validate up to 15,000 emails, import clean contacts, and start sending campaigns — all in one platform.