Boulder
C
C tier on Public Key Infrastructure SoftwareScore 5.4 · #21 of 25
- Android app
- Not listed
- Free plan
- Yes
- Runs on
- api, Linux, self-hosted

Summary
Boulder is ranked #21 of 25 in public key infrastructure software on Everything Xiaomi. It runs on API, Linux, Self-hosted. There is a free plan.
Boulder plans and pricing
All plansOpen source Free MPL-2.0 licensed · production deployment requires separate implementation and security work github.com · 4 Oct 2026
Compared on public key infrastructure software
- Deployment model
- on_premisesgithub.com
- ACME support
- Yesgithub.com
Facts
- Purpose
- Boulder is an ACME-based certificate authority written in Go and is the software that runs Let's Encrypt.github.com · 4 Oct 2026
- Certificate workflow
- ACME lets a certificate authority verify control of an identifier and lets subscribers issue and revoke certificates for identifiers they control.github.com · 4 Oct 2026
- Components
- Boulder includes web front ends, registration and validation authorities, a certificate authority, storage authority, publisher, and CRL updater.github.com · 4 Oct 2026
- Security design
- The component model separates CA functions by security context, with the certificate authority receiving instructions from the registration authority.github.com · 4 Oct 2026
- Interfaces and storage
- Boulder uses gRPC for communication between components and stores ACME accounts, authorizations, challenges, orders, and certificates.github.com · 4 Oct 2026
- Development setup
- The maintainers recommend Docker and Docker Compose for development and experimentation, and the README says this setup is unsuitable for production.github.com · 4 Oct 2026
- Client compatibility
- The README documents running Certbot or another ACME client against a local Boulder instance.github.com · 4 Oct 2026
- Production fit
- Boulder is built for Let's Encrypt and Web PKI baseline requirements, and the maintainers say it is often not a good fit for other organizations' production use.github.com · 4 Oct 2026
- Production security
- The deployment guide says components use mutual TLS issued from a special-purpose CA and describes firewalling components and limiting exposed ports.github.com · 4 Oct 2026
- Production readiness
- The Docker development environment uses publicly available private key material, exposes debug ports, and is described as brittle to component failure.github.com · 4 Oct 2026
- Support
- The maintainers prioritize support and development work that advances Let's Encrypt's mission and warn that timely support may not be available for other deployments.github.com · 4 Oct 2026
- License
- The project is licensed under the Mozilla Public License 2.0.github.com · 4 Oct 2026
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Sources
- github.com/letsencrypt/boulder· checked 4 Oct 2026
- github.com/letsencrypt/boulder/wiki/Deployment-%26· checked 4 Oct 2026
