DigiCert, Sectigo, or Let's Encrypt — Comparing the Major CAs

All browser-trusted Certificate Authorities issue certificates that your users' browsers will accept. The differences are in price, automation, validation depth, support, and features. Here's a practical comparison.

Let's Encrypt

Let's Encrypt is the clear choice for DV automation. Free, ACME-based, 90-day certificates with auto-renewal via Certbot or your hosting provider. It handles the vast majority of new TLS deployments. Limitations: DV only, no OV/EV, 90-day expiry requires automation.

ZeroSSL

ZeroSSL also offers free ACME DV certificates and is a common fallback when Let's Encrypt rate limits are hit. Also offers paid plans with longer validity and OV options. Interface is more user-friendly for those who prefer a GUI over CLI.

DigiCert

DigiCert is the enterprise-grade CA of choice for organizations that need OV, EV, and code signing at scale. Strong validation processes, high-trust brand, and comprehensive account management tools. More expensive than alternatives. Acquired GeoTrust, Thawte, and RapidSSL — all issue under the DigiCert root now.

Sectigo

Sectigo (formerly Comodo CA) offers the full range: DV, OV, EV, and code signing at competitive prices. Good option for organizations that need OV/EV without DigiCert pricing. High issuance volume makes them one of the largest commercial CAs.

GlobalSign

GlobalSign is widely used in enterprise and IoT contexts. Strong API tooling for automated issuance at scale. Good option for organizations managing large certificate inventories programmatically.

AWS Certificate Manager

ACM issues free TLS certificates for use with AWS services (CloudFront, ALB, API Gateway). Auto-renews, integrates seamlessly — but certificates can't be exported to non-AWS infrastructure.

Identifying the Issuing CA

When you decode a certificate with the SSL Certificate Decoder, the Issuer field shows which CA signed it — including the organization name and the specific intermediate CA used.