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 · October 11, 2026
Microsoft makes sending from any alias of an Exchange Online mailbox generally available. How to enable it, its limits, and the SPF, DKIM and DMARC checks to run domain by domain before you turn it on.
CaptainDNS · September 30, 2026
Cloudflare has applied to Chrome, Apple, Microsoft and Mozilla, and signed an agreement to acquire a GlobalSign root. It does not issue any certificates yet. Its first post-quantum certificates (Merkle Tree) are targeted for early 2027, announced as free, via ACME, and reserved for clients that support ARI.
CaptainDNS · September 30, 2026
Since September 23, 2026, Zendesk accounts without sender checks are moving to the Minimal profile. If SPF fails and DKIM is missing or invalid, the message goes to suspended tickets. Here is who is affected and what to check on your domain.
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.