Let's Encrypt - Free SSL Certificates

Basic Information

• Product Name: Let's Encrypt
• Organization: Internet Security Research Group (ISRG)
• Country/Region: United States
• Official Website: https://letsencrypt.org/
• Type: Free, Automated Certificate Authority (CA)
• Founded: December 2015 (Public Release)

Product Description

Let's Encrypt is a free, automated, and open certificate authority operated by the non-profit organization ISRG. It uses the ACME protocol to automate the acquisition and renewal of SSL/TLS certificates, enabling anyone with a domain name to obtain trusted certificates for free, thereby enabling HTTPS encryption. As of 2026, Let's Encrypt holds a 63.9% share of the SSL certificate market, with the majority of the over 112.8 million SSL certificates on the internet issued by Let's Encrypt.

Core Features/Characteristics

• Completely Free: Obtain trusted SSL/TLS certificates at no cost
• Automated: Automatically acquire, configure, and renew certificates via the ACME protocol
• Transparent: All issued and revoked certificates are publicly recorded
• Domain Validation (DV): Supports single-domain and wildcard certificates
• Wide Compatibility: Trusted by almost all modern browsers and operating systems
• Short-Term Certificates: 90-day validity (planned to shorten to 45 days by 2027-2028)
• ACME Clients: Various client tools like Certbot, acme.sh, etc.

Important Updates in 2026

• Removed the "TLS Client Authentication" extended key usage in February 2026
• Plans to shorten certificate validity to 64 days in 2027 and to 45 days in 2028
• Market share reached 63.9%, with over half of the internet's certificates

Business Model

ISRG is a 501(c)(3) non-profit organization, relying on sponsors (Cisco, Akamai, Mozilla, Chrome, etc.) and donations for operation.

Pricing

Completely free.

Statistics (2026)

• Market Share: 63.9% of SSL certificates
• Global SSL Certificates: Over 112.8 million
• Daily Issuance: Millions of certificates

Relationship with OpenClaw

1. VPS Deployment: SSL certificates are needed to protect API communication when OpenClaw is deployed on a VPS
2. Webhook Security: HTTPS is required for webhook callbacks from messaging platforms (WhatsApp, Telegram, etc.)
3. Web Interface: The management web interface of OpenClaw needs HTTPS protection
4. Zero Cost: No additional operational cost for OpenClaw

Advantages

• Completely free, lowering the barrier to HTTPS adoption
• Highly automated (almost zero maintenance with Certbot)
• Widely trusted (almost 100% of browsers/devices)
• Promotes the widespread adoption of internet encryption
• Active community and extensive documentation

Limitations

• Supports only Domain Validation (DV), not Organization Validation (OV) or Extended Validation (EV)
• Short certificate validity (90 days), requiring automatic renewal
• Not suitable for enterprise scenarios requiring OV/EV certificates
• Occasional service outages may affect renewal
• No commercial support

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