Boulder vs EZCA

Boulder is an open-source ACME certificate authority written in Go and used to run Let’s Encrypt. ACME lets a certificate authority verify control of an identifier and allows subscribers to issue or revoke certificates for identifiers they control. Boulder divides its work among web front ends, registration and validation authorities, a certificate authority, storage authority, publisher, and CRL updater. These boundaries separate CA functions by security context, with the certificate authority receiving instructions from the registration authority. Components communicate through gRPC, and the software stores ACME accounts, authorizations, challenges, orders, and certificates. Boulder is free under the Mozilla Public License 2.0 and is listed for API, Linux, and self-hosted use. Maintainers recommend Docker and Docker Compose for development and experimentation, and document connecting Certbot or another ACME client to a local instance. That Docker environment is not suitable for production: it uses publicly available private key material, exposes debug ports, and is described as brittle when components fail. Boulder is built for Let’s Encrypt and Web PKI baseline requirements; maintainers say it often does not fit other organizations’ production needs.

EZCA is a cloud PKI service for running certificate authorities without operating the underlying PKI infrastructure yourself. It issues certificates through ACME, EST, and SCEP, and provides APIs for applications and workflows. Certificate uses include users, devices, applications, Wi-Fi, VPN, web services, and IoT, including device authentication for Azure IoT Hub and Azure IoT Central. Integrations include Azure, Entra ID, Intune, Azure Key Vault, and Azure applications; Intune and Jamf are supported for device certificates. EZCA can chain to an existing on-premises CA or bring an AD CS CA into a cloud setup. The maker says its CAs are HSM-backed, with Basic using FIPS 140-3 Level 2 and Premium Level 3. CA changes, requests, and approvals are logged for export to a preferred SIEM, and revocation checks use CRLs and OCSP. Basic costs $200 a month per CA, and a 30-day trial is available; there is no free plan. Plans differ in throughput, support, availability, and infrastructure options.