Is it safe to paste my SSL certificate here?

Yes. The public certificate is not a secret; it is sent to every browser that connects to your site. The decoder processes it entirely in your browser, so the data never leaves your machine. Never paste your private key, however.

How do I get the PEM certificate from a live website?

In most browsers, click the padlock icon in the address bar, view the certificate, and export it as a PEM or Base64-encoded file. Alternatively, use the command: openssl s_client -connect example.com:443 -showcerts.

What is the difference between a certificate and a private key?

The certificate contains the public key and identity information, and is meant to be shared publicly. The private key is the secret counterpart that must never be disclosed. Together they enable TLS encryption. Only paste the certificate (public) into a decoder, never the private key.

How to Decode an SSL Certificate

4 min readDevOps

SSL/TLS certificates are essential for securing web traffic, but their PEM-encoded format is not human-readable. Decoding a certificate lets you verify the issuer, check the expiration date, confirm Subject Alternative Names (SANs), and inspect the public key, all without command-line tools. This guide shows you how.

Quick Steps

1
Get your certificate
Export the PEM-encoded certificate from your server, CA dashboard, or .crt file.
2
Open the SSL Certificate Decoder
Navigate to the SSL Certificate Decoder tool in Toolin's DevOps category.
3
Paste the PEM block
Paste the full certificate including -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- lines.
4
Review decoded details
Check the subject, issuer, validity dates, SANs, and key information.
5
Verify correctness
Confirm the domain, expiry, and key size match your expectations before deploying.

SSL Certificate Decoder

Parse and inspect SSL/TLS certificates

Open Tool

What Is Inside an SSL Certificate?

Subject — the domain name(s) the certificate is issued for
Issuer — the Certificate Authority (CA) that signed the certificate
Validity period — the Not Before and Not After dates defining when the cert is valid
Subject Alternative Names (SANs) — additional domains covered by the certificate
Public key — the RSA or ECDSA key used for the TLS handshake
Signature algorithm — the hash algorithm used to sign the certificate (e.g. SHA-256 with RSA)

PEM Format Explained

-----BEGIN CERTIFICATE-----
MIIFjTCCA3WgAwIBAgIRANOxcigQ...
(Base64-encoded ASN.1 DER data)
...+bGVhZg==
-----END CERTIFICATE-----

The PEM block contains the certificate's binary
data encoded in Base64 between the BEGIN/END markers.

Decoding a Certificate Step by Step

Obtain the PEM certificate

Export it from your web server config, download it from your CA, or copy it from a .crt or .pem file.

Paste into the decoder

Open the SSL Certificate Decoder tool on Toolin and paste the full PEM block including the BEGIN and END markers.

Review the decoded fields

The tool parses the certificate and displays the subject, issuer, validity dates, SANs, key type, key size, and signature algorithm in a readable format.

Check for issues

Verify that the domain matches your site, the certificate is not expired, and the key size meets current security standards (2048-bit RSA minimum or 256-bit ECDSA).

Common Certificate Problems

Certificate expired — renew with your CA or set up automated renewal via Let's Encrypt / certbot
Domain mismatch — the certificate's CN or SANs do not include the domain visitors are accessing
Incomplete chain — the intermediate CA certificate is missing from the server configuration
Weak key — RSA keys shorter than 2048 bits are considered insecure by modern browsers

Try SSL Certificate Decoder Now — Free, No Sign-up

Frequently Asked Questions

Is it safe to paste my SSL certificate here?: Yes. The public certificate is not a secret; it is sent to every browser that connects to your site. The decoder processes it entirely in your browser, so the data never leaves your machine. Never paste your private key, however.
How do I get the PEM certificate from a live website?: In most browsers, click the padlock icon in the address bar, view the certificate, and export it as a PEM or Base64-encoded file. Alternatively, use the command: openssl s_client -connect example.com:443 -showcerts.
What is the difference between a certificate and a private key?: The certificate contains the public key and identity information, and is meant to be shared publicly. The private key is the secret counterpart that must never be disclosed. Together they enable TLS encryption. Only paste the certificate (public) into a decoder, never the private key.