ZeroSSL

Overview

Founded in 2019 and headquartered in Vienna, Austria, ZeroSSL is a modern SSL certificate authority (CA) focused on simplifying certificate management. ZeroSSL's mission is to make SSL certificate management accessible to everyone — offering free DV certificates through three management modes: an intuitive web dashboard, the standard ACME protocol, and a REST API.

As of 2026, ZeroSSL has issued over 5 million certificates, making it the most popular free CA alternative to Let's Encrypt. Its key differentiator is the web management interface: users can generate CSRs, request certificates, and configure auto-renewal directly in their browser without installing Certbot, acme.sh, or any client software. This "no-install" approach is ZeroSSL's answer to the complexity barrier that has prevented many non-technical website owners from adopting Let's Encrypt.

Key Strengths

• Web-Based Management, Zero Installation: No need to install Certbot, acme.sh, or other clients. Generate CSRs, request certificates, download, and configure renewal entirely in the browser. For non-technical users (WordPress site owners, small business operators), this is the most user-friendly SSL management approach available. Works seamlessly with website builder tools and control panels.
• Dual Management Modes (Web + ACME): Offers both a web interface for manual operations and standard ACME protocol plus REST API for automation. Developers can use ACME clients (acme.sh, Certbot) or programmatic API access. This dual-mode architecture means ZeroSSL serves both non-technical users and DevOps teams on the same platform. See CDN and SSL/TLS configuration best practices for guidance on choosing the right management approach.
• REST API for Bulk Operations: Full REST API supporting batch certificate enrollment, renewal, and revocation. Designed for developers and large-scale deployments requiring programmatic certificate management, integrating with environment deployment pipelines, CI/CD workflows, and container orchestration systems.
• Flexible Paid Plans: Free plan offers 90-day DV certificates; paid plans ($8-$20/month) provide 1-2 year validity, priority support, custom branding, and OV/EV certificate options. This tiered approach lets users start free and upgrade as needs grow.
• In-Browser CSR Generation: No OpenSSL or command-line tools needed. Generate CSRs and private keys directly in the browser with 2048-bit or 4096-bit RSA options. Private keys are generated client-side and never transmitted to ZeroSSL servers.

Product Ecosystem

Free DV Certificate (90-Day)

ZeroSSL's flagship free product. Supports web management, ACME protocol, and REST API. Includes auto-renewal configuration via the dashboard. Suitable for personal websites, blogs, and any HTTPS deployment where 90-day renewal is acceptable.

Starter Plan DV

$8/month ($96/yr). 1-year validity DV certificates. Priority support queue. Same web and API management as free plan. Suitable for users wanting longer validity without the 90-day renewal cycle.

Professional Plan (DV + OV)

$14/month ($168/yr). DV and OV certificates with 1-2 year validity. Custom branding options for certificate details. Suitable for small businesses needing organizational identity verification.

Enterprise Plan (DV + OV + EV)

$20/month ($240/yr). Full DV, OV, and EV certificate support with 1-2 year validity. Priority support and all features. Suitable for e-commerce and financial platforms requiring maximum user trust.

Limitations

• Free Tier DV Only: The free plan only offers DV certificates — no OV or EV. Scenarios requiring organizational identity display must upgrade to paid plans or use a commercial CA like Sectigo.
• Limited Free Support: Free users rely on knowledge base articles and community forums. Support response times can be slow, and there is no phone or live chat support for free accounts.
• ACME Ecosystem Compatibility: While ZeroSSL supports the ACME protocol, integration with mainstream clients like Certbot and acme.sh is less mature than Let's Encrypt. Some advanced automation scenarios (e.g., specific DNS-01 challenge configurations for wildcard certificates) may require manual configuration adjustments.
• Brand Trust Building: As a CA founded in 2019, ZeroSSL's brand recognition and track record are not as established as Let's Encrypt or traditional CAs like DigiCert and Sectigo. Enterprise security and compliance teams may require more time to build confidence in ZeroSSL's operational maturity.

Use Cases

Pricing

Note: Prices are subject to change. Visit the ZeroSSL website for current pricing.

FAQ

• What's the difference between ZeroSSL and Let's Encrypt? Both offer free DV certificates with ACME protocol support. ZeroSSL's key differentiator is its web management interface (no command-line needed) and REST API. Let's Encrypt has a more mature ACME ecosystem and larger community. See CDN and SSL/TLS configuration best practices for guidance.
• Is the ZeroSSL free plan sufficient? Yes for personal blogs, small websites, and testing environments. The free plan supports DV certificates, web management, and ACME protocol. Upgrade to a paid plan if you need OV/EV certificates or longer validity periods—see CDN and SSL/TLS configuration best practices.
• Does ZeroSSL support wildcard certificates? Yes. Both free and paid plans can issue wildcard DV certificates (via DNS-01 challenge). Paid plans can issue wildcard OV certificates—see CDN and SSL/TLS configuration best practices.
• Is ZeroSSL private key handling secure? Yes. ZeroSSL supports in-browser CSR generation — private keys are generated client-side and never transmitted to ZeroSSL servers. Users can choose between 2048-bit or 4096-bit RSA keys—see the website security checklist.
• Is ZeroSSL a publicly trusted CA? Yes. ZeroSSL certificates are publicly trusted in all major browsers and operating systems. The CA operates under rigorous audit and compliance with CA/Browser Forum baseline requirements—see CDN and SSL/TLS configuration best practices.