How to Implement ZeroSSL Certificates in Apache and Nginx: An In-Depth Guide

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As an IT professional and cybersecurity enthusiast, I cannot stress enough the importance of utilizing HTTPS and SSL/TLS certificates to secure websites. Given the sophisticated cyber threats that exist today, taking steps to encrypt web traffic should be a top priority for any website owner.

While obtaining SSL certificates used to be an expensive and complex process, the emergence of free certificate authorities like ZeroSSL has helped democratize encryption for everyone. In this comprehensive guide, I‘ll walk you through everything you need to know to implement ZeroSSL‘s free certificates on Apache and Nginx – the two most popular web servers.

Why HTTPS and SSL Certificates Matter

Before we dive into the implementation details, it‘s worth understanding why HTTPS and SSL certificates are so important:

  • Data encryption – Encrypting connections prevents hackers from intercepting and stealing data like passwords, credit cards, etc. that are transmitted over the internet.

  • Identity verification – Certificates allow visitors to verify they are connecting to the real website, not an imposter site. This builds user trust.

  • SEO boost – Google prioritizes websites using HTTPS, giving them a ranking boost in search results.

  • Compliance – Many industry compliance standards like PCI DSS require the use of encryption. Certificates help meet these requirements.

According to EnterSecurity‘s 2022 Global Encryption Trends study, the use of HTTPS has exploded in recent years:

  • 90% of web traffic is now encrypted, up from just 50% in 2018
  • 78% of sites use HTTPS by default, up from 41% in 2018

However, small sites like personal blogs often still lack encryption. ZeroSSL aims to change that by providing free certificates to everyone.

Introducing ZeroSSL

ZeroSSL is a certificate authority founded in 2018 that provides free SSL certificates using basic domain validation. The key benefits over paid options include:

  • Free – $0 cost makes it accessible to everyone
  • Automatic – Validation and issuance is fully automated for ease of use
  • Unlimited – Can be used on unlimited domains and subdomains
  • Fast – Issued within minutes, ideal for rapid testing and development

The free certificates use domain validation only, meaning ZeroSSL automates checks confirming you control the domain. This level of validation suits most personal sites. Higher levels like extended validation (EV) require business verification for maximum trust, but cost money.

Step-by-Step Guide: Implementing ZeroSSL Certificates

Now, let‘s walk through the full process of obtaining a certificate from ZeroSSL and installing it on Apache and Nginx.

1. Obtain a ZeroSSL Certificate

First, request your free certificate from ZeroSSL:

  1. Create a ZeroSSL account
  2. In the dashboard, click "New Certificate"
  3. Enter your domain name (
  4. Select the 90 day free certificate
  5. Choose automatic CSR generation for simplicity
  6. Verify domain ownership via DNS, Email or File methods
  7. Download ZIP file containing certificate, private key, and bundle

The verification step proves to ZeroSSL you control the domain. For maximum reliability, use DNS verification if you have access to edit domain records.

The entire issuance process only takes a few minutes – significantly faster than paid SSL options. Once complete, you have all the files needed to install the certificate.

2. Install Certificate on Apache

Apache powers over 30% of all websites, making it the most popular web server. Here is how to install a ZeroSSL certificate on Apache:

  1. Install Apache if not already present using apt-get install apache2
  2. Create folder to store certs – mkdir /etc/sslCA
  3. Transfer the ZIP contents to the new directory
  4. Enable SSL mod with a2enmod ssl
  5. Edit Apache config file /etc/apache2/mods-available/ssl.conf
  6. Add certificate, key, and bundle directives:
<VirtualHost _default_:443>
  SSLEngine on
  SSLCertificateFile /path/to/cert.crt
  SSLCertificateKeyFile /path/to/private.key
  SSLCertificateChainFile /path/to/ca_bundle.crt
  1. Save changes and restart Apache – service apache2 restart

The site will now use HTTPS with the ZeroSSL certificate when accessed over port 443!

3. Install Certificate on Nginx

Nginx powers over 30% of websites also, competing closely with Apache. Here is how to install the certificate on Nginx:

  1. Install Nginx – apt install nginx
  2. Start Nginx – systemctl start nginx
  3. Create server block in /etc/nginx/conf.d/
server {
  listen 443 ssl default_server;

  ssl_certificate /path/to/fullchain.crt;
  ssl_certificate_key /path/to/private.key;  
  1. Add certificate directives to nginx.conf
  2. Restart Nginx – systemctl restart nginx

That covers the basic installation steps for Apache and Nginx. Next, let‘s discuss some additional tips for an optimal SSL configuration.

Additional Tips for Robust SSL Configurations

To ensure maximum security, here are some additional recommendations:

  • Automate renewals to avoid disruptions – certificates should be renewed every 90 days
  • Monitor expirations using tools like OpenSSL and Nagios to catch issues early
  • Use DNS verification for wildcard certificates on subdomains
  • Enable HSTS to enforce HTTPS connections
  • Test with SSL scanners like on Qualys SSL Labs to check for vulnerabilities

Proper SSL configuration requires vigilance, so be sure to follow security best practices after the initial installation.


I hope this guide provided a comprehensive overview of utilizing free certificates from ZeroSSL to securely implement HTTPS on your websites. Encrypting web connections has become a mandatory practice for all sites handling user data.

ZeroSSL makes it feasible for anyone to enhance their website security. The automated domain validation and issuance process makes obtaining certs easy and fast. And best of all – it‘s 100% free!

If you found this guide helpful, feel free to share it with anyone looking to add HTTPS to their own site. Together, we can encrypt the entire web! Please reach out if you have any other questions.


Written by Alexis Kestler

A female web designer and programmer - Now is a 36-year IT professional with over 15 years of experience living in NorCal. I enjoy keeping my feet wet in the world of technology through reading, working, and researching topics that pique my interest.