Company Overview

ZeroSSL was founded in 2016 by Greg Chisholm, headquartered in Vienna, Austria. It is a modern SSL certificate authority (CA) offering both free and paid SSL certificates. ZeroSSL is known for its clean, intuitive web management interface, native ACME protocol support, and RESTful API. Unlike traditional CAs, ZeroSSL was designed from the ground up with developer experience in mind, offering a cross-platform ZeroSSL Manager desktop application and multi-account management. It is the most popular free SSL alternative to Let's Encrypt, especially suited for users who prefer a web-based certificate management experience.

Related providers: ZeroSSL Services

Core Products

  • ZeroSSL SSL Certificates: Free 90-day SSL certificates (unlimited renewal), plus paid 1-year OV/EV enterprise-grade certificates.
  • ZeroSSL ACME Client: Built-in ACME automation client with Certbot-compatible command-line operations.
  • ZeroSSL Manager: Cross-platform desktop management tool (Windows/macOS/Linux) providing graphical certificate generation, installation, and monitoring.
  • Let's Encrypt Third-Party Management: ZeroSSL platform also supports managing and deploying Let's Encrypt certificates through its interface.

Core Strengths

  • Free 90-Day Certificates: Free SSL certificates with 90-day validity and unlimited auto-renewal — no payment required for continued use.
  • Web Management Panel: Intuitive online certificate management interface for request, deployment, and monitoring without CLI.
  • ACME + RESTful API: Supports both industry-standard ACME automation and RESTful API for custom integrations.
  • Cross-Platform Desktop Tool: ZeroSSL Manager desktop app covers all major operating systems for offline certificate management.

Key Milestones

  • 2016: Founded by Greg Chisholm as a certificate management tool platform.
  • 2019: Transitioned to a full certificate authority (CA), launching free SSL certificate service.
  • 2020: RESTful API and ZeroSSL Manager desktop app launched for Windows/macOS/Linux.
  • 2021: Paid OV/EV enterprise certificates introduced.
  • 2023: Multi-account management and team collaboration features added.
  • 2026: Ongoing expansion of certificate management ecosystem and ACME compatibility improvements.

Market Position

ZeroSSL competes with the following providers in the free SSL certificate market:

  • Let's Encrypt: Market leader in free SSL; ZeroSSL differentiates via its web UI and multi-platform management tools.
  • BuyPass SSL: Norwegian free CA offering longer 180-day free certificate validity.
  • SSL.com: Paid SSL certificate provider covering commercial and enterprise certificate needs.
  • DigiCert: World's largest paid CA for enterprise PKI/SSL solutions.
  • Sectigo: Global leading commercial CA with comprehensive SSL certificate products.