SieveSimple pricing that scales with your accuracy
Unlimited DNS-layer checks are free, forever. Pay only for live SMTP verification: the step that asks the receiving mail server whether an inbox really exists.
Free
Unlimited DNS checks plus a monthly taste of the live SMTP probe.
Catches bad formatting, dead domains, disposable and role addresses without limits, and confirms up to 100 real mailboxes a month.
- Unlimited DNS checks (syntax, typo, MX, disposable, role)
- 100 live SMTP verifications / month
- Deliverability audit (SPF/DKIM/DMARC)
- Bulk lists & CSV export
- Domain monitoring & alerts
- Webhooks & API access
Pro
15,000 live mailbox verifications every month, with the full evidence trail. Or $290/year.
Every live verdict ships with its receipt: the MX host that answered and the SMTP reply code.
- Everything in Free
- 15,000 live verifications / month
- Verdict receipt: MX host + SMTP code per address
- Catch-all confidence scoring
- Pre-send risk verdict for every list
- Domain monitoring & alerts
- Webhooks on job completion
- Full API access
Checkout opens shortly. Start on Free today and upgrade in-app.
Pay as you go
Buy verification credits and use them whenever you need them. Includes API access.
- Same live SMTP verification as Pro
- Credits never expire
- API access included
- Bulk lists & CSV export
- Deliverability audit
- No monthly commitment
Checkout opens shortly. Start on Free today and upgrade in-app.
How we keep these numbers honest
- Free-mail providers (Gmail, Yahoo, Outlook, iCloud) block mailbox probing for every vendor. We never SMTP-probe them, and we mark those addresses unverifiable instead of pretending they're confirmed.
- Catch-all domains get a confidence score built from real probe evidence. Microsoft 365 catch-alls count as risky, not clean.
- If our outbound SMTP path is ever unavailable, validation degrades to DNS-only and the app tells you so. You're never billed a live verification that didn't run.
Frequently asked questions
Is checking an email address free on Sieve?
Yes. The free plan includes unlimited DNS-layer checks (syntax, typo, MX, disposable and role detection) plus 100 live SMTP mailbox verifications every month, with bulk lists and CSV export included. There is also a free domain deliverability grade at sievemails.com/grade that requires no signup at all.
Do Sieve credits expire?
No. Pay-as-you-go credit packs never expire and carry no subscription or monthly commitment. You buy verification credits once and use them whenever you need them, and API access is included with packs.
How accurate is verification, and what happens when a mailbox cannot be probed?
Sieve tells you the truth. Free-mail providers like Gmail, Yahoo, Outlook and iCloud block mailbox probing for every vendor, so Sieve marks those addresses unverifiable rather than pretending they were confirmed. Every live verdict on Pro ships with its receipt, the MX host that answered and the SMTP reply code, and you are never billed for a live verification that did not run.
Is my email list private? Do you sell my data?
Your lists are never sold and never pooled across customers. Every address is encrypted with AES-256-GCM before it is stored, and when you upload a spreadsheet the rest of your file is encrypted the same way. We keep that file for one reason: so your export can give you back your own columns with a status column added. Raw addresses are never written to application logs, and you can delete any job or wipe everything tied to your account at any time, immediately and permanently. On sievemails.com, stored results and the files they came from are also purged automatically after 90 days.
What is a catch-all domain?
A catch-all domain accepts mail sent to any address at that domain, so a mail server cannot confirm whether a specific mailbox exists. Sieve marks catch-all addresses as risky rather than clean and gives them a confidence score built from real probe evidence, and Microsoft 365 catch-alls count as risky, not clean.
What does the free domain grade check?
The grade tool at sievemails.com/grade checks a sending domain's MX records, SPF, DKIM, DMARC and the major blacklists, then scores it A to F with prioritized, copy-paste fixes. It only reads public DNS records, stores nothing, and requires no signup.
Does Sieve have an API?
Yes. Full API access comes with the Pro plan, and pay-as-you-go credit packs include API access as well. Pro also adds webhooks that fire when a validation job completes.
How much does Sieve Pro cost?
Pro is $29 per month and includes 15,000 live mailbox verifications monthly, along with verdict receipts (the MX host and SMTP code behind each result), catch-all confidence scoring, a pre-send risk verdict for every list, domain monitoring, webhooks and full API access.
What do the clean, risky and rejected verdicts mean?
Clean means the address is well formed, the domain accepts mail, and nothing suggests it will bounce. Risky means deliverable but with a caveat, such as a role inbox like info@, a catch-all domain, or an address that could not be fully verified. Rejected means do not send: the address is invalid, a likely typo, disposable, or the mailbox does not exist. Every result carries a confidence score and a per-layer breakdown.
What is your refund policy?
Payments are processed by Paddle, our merchant of record, which handles all checkout and card data. You are never billed for a live verification that did not run: if Sieve's verification path is ever unavailable, checks degrade to DNS-only and the app tells you so. For any billing issue, contact us and we will sort it out.