What SSL certificate formats does this toolkit support?

The SSL Toolkit supports PEM (Base64 text), DER (binary), PKCS#7/P7B (certificate chains), and PKCS#12/PFX (certificates with private keys). You can convert between formats using the Format Converter tool.

Is it safe to paste my private key into this tool?

Yes! All processing happens entirely in your browser using JavaScript. Your private keys and certificates are never sent to any server. The only exception is the Website SSL Checker, which fetches public certificate data from websites.

What key algorithms are supported for key generation?

The toolkit supports RSA keys (2048, 3072, and 4096 bit), as well as ECDSA keys with P-256, P-384, and P-521 curves. You can also encrypt private keys with a password using PKCS#8 encryption.

How do I check if my certificate matches my private key?

Use the Certificate-Key Matcher tool. Paste both your certificate and private key, and the tool will verify they form a matching pair by comparing their public key components.

Can I check the SSL configuration of any website?

Yes! The Website SSL Checker tool lets you enter any domain name and analyzes its SSL certificate, certificate chain, supported TLS versions, cipher suites, HSTS configuration, and more.

Free Online SSL Toolkit (No Signup)

How to Use This Tool

Pick a tool — Choose from 13 SSL tools in the sidebar: Certificate Decoder, CSR Generator, Key Generator, SSL Checker, and more
Provide input — Paste your certificate, CSR, or private key in PEM format, or upload a file; for SSL Checker, enter a domain name
Process your data — Click the action button to decode, generate, validate, or convert your SSL data instantly
Download or copy results — Export generated certificates and keys, copy decoded details, or add entries to the Expiry Tracker

Common Use Cases

How do I decode an SSL certificate to see its details? Paste the PEM-encoded certificate into the Certificate Decoder to view subject, issuer, validity, SANs, and key info
How do I generate a CSR for a new SSL certificate? Use the CSR Generator to fill in your organization details and key type, then download the CSR and private key
How do I check if my certificate and private key match? Use the Certificate-Key Matcher tool to paste both and verify they form a valid pair

Privacy: Certificate decoding, CSR and key generation, matching, and format conversion all run entirely in your browser — your certificates and private keys are never uploaded or sent to any server. The only exception is the Website SSL Checker, which sends just the domain name you enter to our server so it can fetch that site's public SSL configuration. Tracked-certificate data is stored locally in your browser only.