Domain, IP, email, URL or raw DNS record. We detect the input and run the right audit in under 3 seconds.
For the parts of your stack that need uptime, alerts and a real owner, not a one-off check.
Real-time rua/ruf reports, sender breakdowns and alerts when alignment breaks.
Continuous monitoring of your email security and deliverability. Get alerted whenever a score or DNS record changes enough to affect deliverability or security.
Multi-region uptime checks, 3-region consensus, alerts. Security score: SSL/TLS, HSTS, headers, phishing.
Public status pages tied to your monitors. Custom domain, incidents, subscribers, RSS. Publishable Security score.
Host 301/302 redirects with HTTPS and per-link analytics. No server to maintain.
Audit tools stay free. Pay only for continuous monitoring, per tool.
Start with 1 free tool, no credit card.
Uptime
Monitor the availability and latency of your websites, with an alert as soon as a problem occurs.
€3 /month excl. VAT
Email deliverability
Keep a constant eye on email security and deliverability to spot problems before your messages end up in spam.
€5 /month excl. VAT
DMARC
Receive and understand your aggregate DMARC reports to keep SPF and DKIM aligned, without reading them line by line.
€5 /month excl. VAT
TLS-RPT
Spot invisible SMTP encryption failures by analyzing your TLS reports.
€3 /month excl. VAT
BIMI
Display your authenticated brand logo in compatible inboxes by hosting the logo and VMC certificate.
€3 /month excl. VAT
MTA-STS
Host your MTA-STS policy to enforce encryption for incoming email without managing a server.
€3 /month excl. VAT
Domain redirect
Redirect your domains over HTTPS, with a managed TLS certificate that renews automatically.
€3 /month excl. VAT
1 free tool
Discovery version
0 € /month excl. VAT
For teams, a plan
10 tools to combine freely across all 7 types, plus the platform, for teams monitoring several domains.
For agencies and MSPs: 100 tools, white-label branding, multi-client management.
No credit card · No commitment · Cancel anytime.
Pick a category. Each tool ships with a live output preview.
Deep dives on DMARC, DNSSEC, deliverability and modern email security.
CaptainDNS · September 17, 2026
RFC 10023 describes a DNS signal for domains that are for sale, even while their websites and email remain active. Learn how to read the _for-sale TXT record and what to check before contacting a seller.
CaptainDNS · September 16, 2026
Persistent DNS validation does not guarantee renewals without intervention. Here is its status on September 16, 2026, its limitations and the criteria for deciding whether it suits your TLS certificates.
CaptainDNS · September 9, 2026
Removing an accent changes the domain name. Find the right DNS zone behind its displayed form and understand the consequences for SPF, DKIM and DMARC.
Everything you wanted to know before signing up.
The 60+ audit tools stay free, no sign-up required. Continuous monitoring: 1 tool in discovery mode, free without a credit card. Each extra tool is billed per unit (€3 or €5/month).
Yes. Add or remove tools at any time, with no commitment. Billing is monthly and prorated by Paddle.
Audits run on the fly and are not persisted unless you save them in your account. We keep aggregate counters only, no PII, no third-party trackers.
Yes. Everything is monthly, with no commitment: each tool costs €3 or €5 per month. Payments are handled by Paddle (card, PayPal, Apple/Google Pay).
Every free account gets 30 API credits per month, 50,000 with the Pack. Monitoring tools have no cap: each tool beyond the free one is billed per unit.
Credit card (Visa, Mastercard, Amex), PayPal, Apple Pay and Google Pay via our billing partner Paddle. Enterprise contracts support wire transfer and SEPA.
We parse rua and ruf reports in real time, deduplicate senders, expose failures with actionable signals and alert you when alignment breaks. EU hosting, no resale.
Yes on Agency and Enterprise. Okta, Google Workspace and Azure AD are supported out of the box; custom SAML on Enterprise.