Are my certificates and private keys safe?

Yes. All decoding and inspection operations run entirely in your browser. No certificate data, CSRs, or keys are sent to any server.

Which certificate formats are supported?

PEM-encoded certificates (-----BEGIN CERTIFICATE-----) are supported by all tools. DER certificates can be converted to PEM first using the DER to PEM converter.

Can I decode a full certificate chain?

Yes. Paste a full chain (root, intermediate, and leaf certificates concatenated in PEM format) and each certificate in the chain is decoded separately.

Manage SSL Certificates Online

SSL/TLS certificate management involves a range of inspection and verification tasks that traditionally require OpenSSL command-line tools. devtoolkit.sh makes these tasks accessible in any browser without installing anything. Decode a PEM certificate to inspect all fields — issuer, subject, SANs, validity dates, and key details. Check when a certificate will expire to plan renewals before downtime. Decode a CSR to verify the details before submitting it to a CA. Calculate the certificate fingerprint for comparison and pinning. All operations run entirely in your browser, so private keys, CSRs, and certificates are never transmitted anywhere. This toolkit is essential for DevOps engineers, backend developers, and security teams managing certificate lifecycles.

#SSL Certificate Decoder

Paste a PEM certificate and decode its subject, issuer, validity dates, SANs, and more.

#SSL Expiry Calculator

Find out how many days until an SSL certificate expires. Paste a PEM or enter a date.

#CSR Decoder

Paste a PEM CSR and decode its subject, public key algorithm, and signature algorithm.

#Certificate Fingerprint Calculator

Calculate SHA-1 and SHA-256 fingerprints of a PEM certificate in colon-separated hex.

FAQ

Are my certificates and private keys safe?: Yes. All decoding and inspection operations run entirely in your browser. No certificate data, CSRs, or keys are sent to any server.
Which certificate formats are supported?: PEM-encoded certificates (-----BEGIN CERTIFICATE-----) are supported by all tools. DER certificates can be converted to PEM first using the DER to PEM converter.
Can I decode a full certificate chain?: Yes. Paste a full chain (root, intermediate, and leaf certificates concatenated in PEM format) and each certificate in the chain is decoded separately.