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Boulder

No phone app

6.0No. 14 of 18
in Public Key Infrastructure Software
  • Recognised40% of the score11
  • Phone app26% of the score0
  • Documented20% of the score81
  • Free plan14% of the score100
Free plan
Yes
Runs on
api, Linux, self-hosted
Visit site Alternatives

Summary

Boulder is ranked #14 of 18 in public key infrastructure software on Samsung Mobile US Press. It runs on API, Linux, Self-hosted. There is a free plan.

Boulder plans and pricing

All plans
Open 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

Best Boulder alternatives

See all 12
Entrust Certificate Manager No. 1 8.2 iPhone + AndroidEZCA No. 2 8.0 iPhone + Android$200/moXiPKI No. 3 7.8 No phone appFreeKeyTalk CKMS No. 4 7.6 iPhone + Android€5/moDigiCert Private CA No. 5 7.4 No phone appAppViewX PKIaaS No. 6 7.1 No phone app

Where it ranks on Samsung Mobile US Press

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Sources