Bulk Email Validator API for cold-outbound list cleaning — SMTP probe, MX record lookup, catch-all detection, disposable / role-account flagging, and per-email deliverability scoring. Pay-per-result on Apify at fractions of a cent per address vs $16-199 per 10K for ZeroBounce, $10-200 for NeverBounce, and $20-300 for EmailListVerify.
Email deliverability is the single biggest preventable killer of cold-outbound and newsletter campaigns. A list with 5-10% invalid addresses gets flagged by Gmail and Outlook spam filters within 24-48 hours, drops sender reputation across the entire sending domain, and torches the deliverability of every other campaign you run that month. Bouncing 200 emails in a 2,000-address send drops your inbox-placement rate from 92% to under 50% — verified by every major deliverability vendor (Validity, Litmus, Mailgun) over the last decade.
The fix is well-understood: run every address through SMTP-probe + MX-lookup + catch-all detection before you send, and drop anything flagged invalid, risky, or disposable. The problem is the existing market: ZeroBounce, NeverBounce, Kickbox, Bouncer, and MillionVerifier all charge $16-300 per 10K emails on monthly plans, with most tiers requiring you to pre-buy credits that expire if unused. For a small SDR team running 5K-50K addresses a month, that’s $50-500/mo committed up front for a workload that varies week-to-week.
The NexGenData Bulk Email Validator runs the same SMTP-probe + MX + catch-all checks, pay-per-result on Apify. No monthly minimum, no expiring credits, no per-seat licensing. Just upload a CSV or pipe in JSON, get back deliverability + risk scoring per email, pay for what you actually verified.
Sample output — bulk validation
| status | mx_found | smtp_check | catch_all | disposable | role | score | |
|---|---|---|---|---|---|---|---|
| jane@acme.com | valid | yes | 250 OK | no | no | no | 98 |
| info@acme.com | risky | yes | 250 OK | no | no | yes | 52 |
| bob@tempmail.io | invalid | yes | 550 No such user | no | yes | no | 4 |
| sales@megacorp.com | unknown | yes | 250 (catch-all) | yes | no | yes | 38 |
| amir@nonexistentdomain.xyz | invalid | no | n/a | n/a | n/a | n/a | 0 |
Standard advice from ESPs: drop everything with status=invalid or score < 30. Treat risky as send-on-warm-up-IPs only. Send to valid from your primary cold-outbound infrastructure.
Why this beats ZeroBounce, NeverBounce, Kickbox & MillionVerifier
| Feature | NexGenData Email Validator | ZeroBounce | NeverBounce | EmailListVerify | Hunter Verifier | Kickbox / Bouncer |
|---|---|---|---|---|---|---|
| Cost — 10K emails verified | ~$24 (pay-per-result) | $16-199 | $10-200 | $20-300 | Bundled $49-499/mo | $30-225 |
| Cost — 100K / month | ~$240 | $390-1,500 | $250-2,000 | $200-2,500 | $499/mo+ | $400-2,250 |
| Monthly minimum / pre-buy credits | None — pay per result | Credits expire 1yr | Credits expire | Credits expire 1yr | Monthly subscription | Credits expire |
| SMTP probe | Yes | Yes | Yes | Yes | Yes | Yes |
| MX record check | Yes | Yes | Yes | Yes | Yes | Yes |
| Catch-all detection | Yes | Yes | Yes | Yes | Yes | Yes |
| Disposable / temp-mail detection | Yes | Yes | Yes | Yes | Yes | Yes |
| Role-account flagging (info@, sales@) | Yes | Yes | Yes | Yes | Yes | Yes |
| Deliverability score (0-100) | Yes | Yes | Yes | Yes | Yes | Yes |
| Composable with B2B discovery actors | Yes — chain to enrichment | No | No | No | Hunter ecosystem only | No |
| API + bulk CSV upload | Yes (Apify API) | Yes | Yes | Yes | Yes | Yes |
| Free tier | Yes — $5/mo Apify credits | 100 free | 1K free | 100 free | 50 free/mo | 100 free |
Use cases
B2B SDR: clean a 30K cold-outbound list before sending
A 3-person SDR team buys or builds a 30K-address cold-outbound list per quarter. Run it through the Email Validator before importing into Apollo, Outreach, Smartlead, or Instantly. Typical results: 8-15% flagged invalid (immediate drop), 5-8% flagged risky catch-all (route through warm-up IPs only), 2-4% disposable / temp-mail (drop). Net: a 20-25% reduction in send volume but a 3-5x improvement in inbox-placement rate, which compounds because sender-reputation damage avoided here keeps your other campaigns landing inbox too. Cost at 30K addresses: ~$70 vs $50-600/month for the equivalent monthly tier on ZeroBounce or NeverBounce.
Email marketer: validate a 500K newsletter list pre-Klaviyo / Mailchimp import
Newsletter lists migrating between ESPs (Klaviyo → Mailchimp, ActiveCampaign → ConvertKit) need to be validated before the import or the new ESP’s deliverability heuristics will throttle you for weeks. Pay-per-result validation at ~$0.0024/email lets you validate a 500K list for ~$1,200 — a fraction of the $1,500-3,000 ZeroBounce would charge at the same volume tier, with no expiring credits.
Deliverability ops: weekly hygiene sweep on a 2M-subscriber list
For ongoing list hygiene on a large transactional or newsletter list, run a weekly delta validation (new signups + addresses that bounced softly + addresses that haven’t engaged in 90 days). Pay-per-result fits this workload perfectly: 80K-200K addresses per week, no need to commit to a $999/month MillionVerifier or ZeroBounce enterprise tier.
Klaviyo / ActiveCampaign / MailPoet power user: raw control
Klaviyo, ActiveCampaign, and MailPoet all offer built-in validation, but the controls are limited and the per-validation cost is bundled into the platform tier. For users who want raw output (full SMTP response codes, MX details, catch-all status, custom score thresholds) and the ability to apply different drop policies per campaign, running validation outside the ESP gives full control. Export filtered lists back to the ESP via standard CSV.
Indie hacker: build your own outbound product
Building a Smartlead, Instantly, or Lemlist competitor requires an embedded validation layer. Reselling ZeroBounce or NeverBounce inflates COGS and bakes vendor lock-in into your product. Running validation via Apify lets you mark up at a margin you control, with no monthly commitment up front.
Sister actors — compose the lead-gen stack
The Email Validator is the deliverability layer of a complete B2B outbound stack. The full chain: discovery → enrichment → contact discovery → validation → send. NexGenData publishes actors for every stage.
- Company Email Finder — role-targeted email discovery (CEO, VP Eng, Head of Marketing)
- Contact Info Scraper — bulk emails + phones from any domain
- Lead List Enricher — firmographics + tech stack on top of any company list
- B2B Leads Finder — Apollo-alternative B2B contact discovery
- DMARC Bulk Auditor — SPF / DKIM / DMARC compliance for your own sending domains
- Email RBL Checker — blacklist check for sending IPs and domains
- Website Email Extractor — crawl-based extraction from any company website
Frequently asked questions
How does the validator compare to ZeroBounce, NeverBounce, and Kickbox?
Same core technique (SMTP probe + MX lookup + catch-all detection + disposable / role flagging + deliverability score). Different pricing model — pay-per-result instead of monthly credit packs that expire. For a team verifying under 100K emails/month, the cost is typically 40-80% lower. For teams that already have a ZeroBounce or NeverBounce contract and are happy with it, there’s no urgent reason to switch. For teams that haven’t bought yet or whose contract is up for renewal, the pay-per-result model removes the commit-and-pre-buy friction.
What’s the accuracy rate?
SMTP-probe-based validation has an inherent ceiling around 92-96% accuracy across all major providers (ZeroBounce, NeverBounce, ours, Kickbox, etc.) — the limit is set by catch-all domains, which return 250 OK for any address whether it exists or not. The validator marks catch-all addresses as risky with score 30-50 rather than guessing. Your downstream send strategy decides whether to send (warm IPs only) or drop. Our accuracy on non-catch-all domains is on par with the leading paid providers and we publish accuracy benchmarks per refresh.
What does “catch-all” mean and why does it matter?
A catch-all domain accepts mail to any address @yourcompany.com, even addresses that don’t exist. Many corporate domains run catch-all to forward typos to admin. This means SMTP probes always return 250 OK and you can’t tell whether the address is real. Catch-all addresses are not invalid, but they have a higher hard-bounce rate when sent to — typically 5-15% vs <1% for confirmed-valid. The validator flags catch-all so you can route them through dedicated warm-up IPs or drop them entirely from cold-outbound.
Can I bulk-upload a CSV?
Yes. The actor accepts CSV upload via the Apify console, JSON array via the Apify API, or programmatic input from any pipeline. For large lists (50K+ addresses), the actor parallelizes across multiple workers and returns results within 10-30 minutes. Output is JSON, CSV, or Excel — pick whatever your downstream tool reads.
Does it work with disposable / temp-mail addresses?
Yes — disposable addresses (mailinator, tempmail, 10minutemail, guerrillamail, plus 200+ other domains) are flagged with disposable=yes and score 0-10. Standard practice is to drop these from any signup form or cold-outbound list. The disposable list is refreshed weekly to catch new temp-mail providers as they launch.
Will this protect my sender reputation?
Validating before send is one of three layers of sender-reputation protection (the others are SPF/DKIM/DMARC alignment and engagement-based warm-up). Validation removes the hard-bounce signal that ISPs use to flag senders. Combined with proper SPF/DKIM/DMARC (audit via the DMARC Bulk Auditor) and IP warm-up, you preserve inbox-placement rates above 90%.
How fresh is the validation? Do you cache?
Every check is a live SMTP probe against the receiving server’s MX at runtime — there is no cache. Each verification reflects the mailbox state as of that moment. For ongoing list hygiene, run a weekly delta sweep rather than relying on cached results from 6 months ago.
Is bulk SMTP probing legal? GDPR / CAN-SPAM concerns?
SMTP probing (HELO / MAIL FROM / RCPT TO without DATA) is industry-standard validation used by every major email service. It does not send mail, does not store the address content beyond the validation log, and does not constitute marketing communication. For B2B addresses, CAN-SPAM and GDPR legitimate-interest both cover this. For consumer addresses (B2C), you should have a clean signup-consent record regardless — but validation itself is not the legally-questionable step, the eventual send is.
NexGenData publishes 260+ buyer-intent actors covering email deliverability, sales intelligence, real estate, news, and competitive intelligence — all pay-per-result. Browse the full catalog →