Free tools for certificates and email.
For anyone who installs, renews or troubleshoots certificates. No sign-up. The tools that handle private keys run only in your browser: the key never leaves your computer.
SSL/TLS checker
Test the certificate, chain and protocols of any server: website, mail server or API.
Public data onlyCertificate decoder
See what is inside a certificate: names, validity, issuer, validation type and fingerprints.
Public data onlyCSR decoder
Check your certificate request before you send it: names, organisation, key and signature.
Public data onlyCSR generator
Create the private key and the CSR in your browser, or copy a ready-made OpenSSL command.
Runs in your browserKey matcher
Confirm that a certificate, a CSR and a private key belong together.
Runs in your browserSSL converter
Tell us where the certificate is going (Plesk, nginx, Windows, HAProxy, Java) and get the right files. PEM, DER, P7B and PFX, without the key leaving your computer.
Runs in your browserCertificate Transparency lookup
Find every valid certificate issued for your domain and its subdomains in the public Certificate Transparency logs.
Public data onlyCAA checker
See which Certification Authorities may issue for your domain, before you order.
Public data onlyEmail security check
Check SPF, DKIM, DMARC, BIMI, MTA-STS and TLS-RPT for your domain in one test.
Public data onlyUse the tools through an API or in your AI assistant.
A free public REST API, an OpenAPI specification and an MCP server for Claude and other assistants. No sign-up.
curl "https://digitaltrust.pt/api/v1/ssl/check?host=company.eu"
Specialised checks.
The BIMI record and brand certificate, the S/MIME signature of an email you received and the status of an LEI have their own checkers, on each service's page.