Complete Guide to Free SSL Certificate Tools
Master the essential SSL tools used by security professionals worldwide. Our comprehensive guide covers CSR generation, SSL checking, certificate conversion, and more—all processed securely in your browser.
Why SSL Certificate Tools Matter
Managing SSL/TLS certificates is a critical responsibility for anyone running a secure website. Whether you're a web developer deploying your first HTTPS site, a system administrator managing hundreds of servers, or a security professional auditing certificate configurations, having the right tools makes all the difference.
Our free SSL certificate tools are designed by security experts with over 10 years of experience in PKI and certificate management. Every tool processes data entirely in your browser—your private keys and sensitive information never leave your device.
100% Client-Side Processing
All cryptographic operations happen in your browser using the Web Crypto API and node-forge library. Your private keys are never transmitted over the network.
If you're new to SSL certificates, we recommend starting with our guide on what SSL certificates are and how SSL/TLS encryption works before diving into the tools.
CSR Generator
Create Certificate Signing Requests
A Certificate Signing Request (CSR) is the first step in obtaining an SSL certificate. The CSR contains your public key and organization information, which the Certificate Authority (CA) uses to issue your certificate. Our CSR Generator creates industry-standard RSA key pairs and properly formatted CSRs compatible with all major CAs.
How to Use the CSR Generator
Enter Your Common Name
The Common Name (CN) is your fully qualified domain name. Enter example.com to cover both example.com and www.example.com automatically. If you enter www.example.com, it covers only that specific hostname.
Fill Organization Details
Enter your organization name, department (OU), city, state, and country. For OV SSL and EV SSL certificates, this information will be verified by the CA.
Add Subject Alternative Names (Optional)
For multi-domain certificates, add additional domains as SANs. Type each domain and press Enter to add it. The generator supports unlimited SAN entries.
Choose Key Size
Select 2048-bit for standard security (faster) or 4096-bit for enhanced security (recommended for financial or healthcare applications).
Generate & Save
Click "Generate CSR" to create your CSR and private key. Save both files securely—you'll need the CSR for your CA and the private key for server installation.
Keep Your Private Key Safe
Never share your private key with anyone, including the CA. Store it securely and back it up—if you lose it, you'll need to reissue your certificate.
CSR Decoder
Verify CSR Contents Before Submission
Before submitting your CSR to a Certificate Authority, it's essential to verify that all information is correct. Errors in your CSR can cause certificate issuance delays or result in a certificate with incorrect information. The CSR Decoder extracts and displays all embedded data for your review.
Information Extracted by the CSR Decoder
Subject Information
- • Common Name (CN) - Your domain
- • Organization (O) - Company name
- • Organizational Unit (OU)
- • Location (City, State, Country)
Technical Details
- • Public Key Algorithm (RSA)
- • Key Size (2048, 4096 bits)
- • Signature Algorithm
- • Subject Alternative Names
Pay special attention to the Subject Alternative Names (SANs) if you're ordering a multi-domain certificate. Each SAN domain will be secured by the certificate, so ensure all required domains are listed.
SSL Checker
Analyze Certificate Health & Security
The SSL Checker performs a comprehensive analysis of any website's SSL/TLS configuration. Using industry-standard SSL Labs technology, it evaluates certificate validity, chain of trust, protocol support, and potential vulnerabilities. This is the same tool security professionals use to audit HTTPS configurations.
What the SSL Checker Analyzes
Checks expiration date, domain coverage, and proper issuance
Verifies complete chain from leaf to root CA with proper intermediate certificates
Identifies supported TLS versions and flags deprecated protocols
Detects expired certs, self-signed issues, weak algorithms, and revocation status
SSL Expiry Reminder Service
After checking your SSL certificate, you can subscribe to our free expiry reminder service. We'll email you 1, 3, 7, 14, 30, 60, or 90 days before your certificate expires—you choose the timing. Never miss a certificate renewal again.
Understanding SSL grades and what they mean for your security is covered in our article on how SSL/TLS encryption works.
Secure Your Website Today
Now that you understand SSL tools, get your certificate
Domain Validated SSL
Starting at $2.99/year/year
- 256-bit Encryption
- Unlimited Server Licenses
- Quick Issuance
Certificate Converter
Transform Between Certificate Formats
Different servers and applications require certificates in specific formats. The Certificate Converter handles all common transformations, making it easy to deploy your certificate across various platforms. All conversions happen locally in your browser.
Supported Conversions
PEM ↔ DER
Convert between Base64-encoded PEM and binary DER formats.
Use case: Java applications often need DER format
PKCS#12 → PEM
Extract certificate and key from .pfx/.p12 bundles.
Use case: Migrating from Windows IIS to Apache/Nginx
RSA Key → PKCS#8
Convert traditional RSA keys to PKCS#8 format.
Use case: Required by some Java and cloud platforms
Server Format Requirements
• Apache/Nginx: PEM (.crt, .key)
• Windows/IIS: PKCS#12 (.pfx)
• Java: JKS or PKCS#12
For a deeper understanding of certificate types and their uses, see our guide on SSL certificate types.
Key Matcher
Verify Certificate & Key Pair Compatibility
One of the most common SSL installation errors is using a mismatched private key and certificate. The Key Matcher compares the public key modulus in your certificate, CSR, and private key to verify they all belong to the same key pair.
How Key Matching Works
Every RSA key pair has a unique "modulus"—a large number that appears in both the public and private key. The Key Matcher extracts this modulus from each input and compares them. If all modulus values match, your files are compatible.
Common Mismatch Scenarios
- Generated a new CSR but used an old private key file
- Mixed up keys from multiple domains or certificate orders
- Certificate was reissued with a new CSR but old key is being used
- Private key file was corrupted during transfer or storage
Certificate Decryptor
Decrypt Password-Protected Private Keys
Private keys are often encrypted with a passphrase for additional security. The Certificate Decryptor removes this encryption, outputting a standard unencrypted key that can be used for server installation. This is commonly needed when migrating certificates between servers.
Security Consideration
Decrypted private keys should be handled with care. Ensure your server is properly secured, and consider re-encrypting the key with your server's native tools after installation.
Certificate Decoder
Inspect Full Certificate Details
The Certificate Decoder parses any PEM-encoded X.509 certificate and displays all embedded information in a readable format. This is essential for verifying certificates before installation, auditing existing certificates, or troubleshooting SSL issues.
Information Revealed
Understanding certificate structure and Public Key Infrastructure (PKI) helps you better interpret the decoder output.
SSL Certificate Management Best Practices
Regular SSL Audits
Check your SSL certificates monthly using the SSL Checker. Monitor for upcoming expirations, protocol updates, and security advisories.
Renewal Workflow
Set up expiry reminders 30 days before expiration. Generate a new CSR, order your certificate, and test before the deadline.
Private Key Security
Store private keys in secure locations with restricted access. Use encrypted backups and consider hardware security modules for critical systems.
Verification Process
Always verify CSRs before submission, match keys before installation, and test certificates in staging before production deployment.
Need Professional SSL Certificates?
Browse our complete range of trusted SSL solutions
All SSL Certificates
Starting at From $2.99/year/year
- DV, OV, EV Options
- Wildcard Available
- Trusted by All Browsers
Frequently Asked Questions
Sources & References
Official documentation and industry standards cited in this article
- RFC 2986 - PKCS #10: Certification Request SyntaxIETF·RFC·Accessed January 2026
- RFC 5280 - X.509 PKI Certificate ProfileIETF·RFC·Accessed January 2026
- Web Crypto API SpecificationW3C·Standard·Accessed January 2026
- NIST SP 800-57 Key Management GuidelinesNIST·Standard·Accessed January 2026
Ready to Use These SSL Tools?
Access all 7 free SSL certificate tools instantly. No registration required, 100% client-side processing, completely free.
Access Free SSL Tools