Best Public Key Infrastructure Software in 2026
Updated
In short: OpenCA PKI is ranked #1 of 25 as of 7 October 2026, ahead of step-ca and OpenXPKI. The best-ranked option with a free plan is step-ca. The lowest first paid tier on this page is Microsoft Cloud PKI at $2/mo.
Public key infrastructure (PKI) software is used to manage digital certificates and the trust they establish. Compared on ACME, EST, and SCEP support, certificate profiles, and HSM integration, these entries also differ in deployment model, free-plan availability, and paid-from pricing. OpenCA PKI, step-ca, and XiPKI are among the options shown, alongside Boulder and Entrust Certificate Manager. Consider which enrollment protocols and certificate controls matter for your setup, then weigh the available deployment and cost details against your requirements.
25 public key infrastructure software ranked on what their makers publish — plans and prices, free tiers, platforms and the facts on their own pages.
6 of the 25 here have a free tier you can use, 0 have open-source code on record, and 0 have full bars: free, open, on most of your devices and documented.
| # | App | Signal | Free tier | Open code | Devices | From | Score |
|---|---|---|---|---|---|---|---|
| 1 | OpenCA PKIWeb · Mac · Linux · Self-hosted | Three bars | — | 3 of 6 | Free | 6.5 | |
| 2 | step-caWindows · Mac · Linux · Self-hosted · API | Three bars | — | 3 of 6 | Free | 6.5 | |
| 3 | OpenXPKIWeb · Linux · Self-hosted · API | Two bars | — | 2 of 6 | Free | 6.4 | |
| 4 | XiPKIMac · Linux · Self-hosted · API | Two bars | — | 2 of 6 | Free | 6.4 | |
| 5 | BoulderLinux · Self-hosted · API | Two bars | — | 1 of 6 | Free | 6.3 | |
| 6 | cert-managerLinux · Self-hosted · API | Two bars | — | 1 of 6 | Free | 6.3 | |
| 7 | SecureW2 Cloud NACWeb · Windows · Mac · Linux · Android · iPhone · API | Two bars | — | — | 6 of 6 | — | 5.8 |
| 8 | KeyTalk CKMSWindows · Mac · Linux · Android · iPhone · Self-hosted | Two bars | — | — | 5 of 6 | €5/mo | 5.7 |
| 9 | Cloudflare Serverless RegistryWindows · Mac · Linux · Self-hosted | Two bars | — | — | 3 of 6 | — | 5.6 |
| 10 | Entrust Certificate ManagerWeb · Linux · Android · iPhone · Self-hosted · API | Two bars | — | — | 4 of 6 | — | 5.6 |
| 11 | HashiCorp NomadWeb · Windows · Mac · Linux · Self-hosted · API | Two bars | — | — | 4 of 6 | — | 5.6 |
| 12 | DigiCert Private CAWeb · Linux · Self-hosted · API | One bar | — | — | 2 of 6 | — | 5.5 |
| 13 | Keyfactor PlatformWeb · Self-hosted · API | One bar | — | — | 1 of 6 | — | 5.5 |
| 14 | SSL.com Certificate Lifecycle ManagementWeb · API | One bar | — | — | 1 of 6 | — | 5.5 |
| 15 | EZCAWeb · Windows · Mac · Linux · Android · iPhone · Self-hosted · API | Two bars | — | — | 6 of 6 | $200/mo | 5.4 |
| 16 | GlobalSign AtlasWeb · API | One bar | — | — | 1 of 6 | — | 5.4 |
| 17 | EJBCAWeb | No signal | — | — | 1 of 6 | — | 5.1 |
| 18 | Sectigo Certificate ManagerWeb · API | One bar | — | — | 1 of 6 | $20.83/mo | 5.1 |
| 19 | AppViewX PKIaaSWeb · Self-hosted · API | One bar | — | — | 1 of 6 | — | 5.0 |
| 20 | AWS Private Certificate AuthorityWeb · API | One bar | — | — | 1 of 6 | $50/mo | 5.0 |
| 21 | Dogtag Certificate SystemLinux | No signal | — | — | 1 of 6 | — | 5.0 |
| 22 | Let's EncryptNo platforms listed | No signal | — | — | 0 of 6 | — | 5.0 |
| 23 | Smallstep ZTNAWindows · Mac · Linux · iPhone | One bar | — | — | 4 of 6 | — | 5.0 |
| 24 | Microsoft Active DirectoryWindows | One bar | — | — | 1 of 6 | $33.58/mo | 4.9 |
| 25 | Microsoft Cloud PKIWindows · Mac · Android · iPhone | One bar | — | — | 4 of 6 | $2/mo | 4.9 |
Compare all 25 in a table
| # | App | Score | Free plan | From | Free plan | Paid from | Deployment model | ACME support |
|---|---|---|---|---|---|---|---|---|
| 1 | OpenCA PKI | 6.5 | Free plan | Free | Yes | — | on_premises | — |
| 2 | step-ca | 6.5 | Free plan | Free | Yes | — | hybrid | Yes |
| 3 | OpenXPKI | 6.4 | Free plan | Free | Yes | — | — | — |
| 4 | XiPKI | 6.4 | Free plan | Free | — | — | on_premises | Yes |
| 5 | Boulder | 6.3 | Free plan | Free | — | — | on_premises | Yes |
| 6 | cert-manager | 6.3 | Free plan | Free | Yes | — | — | — |
| 7 | SecureW2 Cloud NAC | 5.8 | No | — | — | — | cloud | Yes |
| 8 | KeyTalk CKMS | 5.7 | No | €5/mo | — | — | — | — |
| 9 | Cloudflare Serverless Registry | 5.6 | No | — | — | — | on_premises | — |
| 10 | Entrust Certificate Manager | 5.6 | No | — | — | — | — | — |
| 11 | HashiCorp Nomad | 5.6 | No | — | Yes | — | — | — |
| 12 | DigiCert Private CA | 5.5 | No | — | — | — | hybrid | Yes |
| 13 | Keyfactor Platform | 5.5 | No | — | — | — | — | — |
| 14 | SSL.com Certificate Lifecycle Management | 5.5 | No | — | Yes | — | cloud | Yes |
| 15 | EZCA | 5.4 | No | $200/mo | No | 200 /mo | hybrid | Yes |
| 16 | GlobalSign Atlas | 5.4 | No | — | — | — | cloud | Yes |
| 17 | EJBCA | 5.1 | No | — | Yes | — | — | — |
| 18 | Sectigo Certificate Manager | 5.1 | No | $20.83/mo | — | — | cloud | Yes |
| 19 | AppViewX PKIaaS | 5.0 | No | — | No | — | cloud | Yes |
| 20 | AWS Private Certificate Authority | 5.0 | No | $50/mo | No | 50 /mo | cloud | — |
| 21 | Dogtag Certificate System | 5.0 | No | — | Yes | — | — | — |
| 22 | Let's Encrypt | 5.0 | No | — | Yes | — | — | — |
| 23 | Smallstep ZTNA | 5.0 | No | — | — | — | — | — |
| 24 | Microsoft Active Directory | 4.9 | No | $33.58/mo | No | — | — | — |
| 25 | Microsoft Cloud PKI | 4.9 | No | $2/mo | No | — | — | — |
Is your app on this list?
Numbered spots on this list can be sponsored, and a sponsored row is labelled as paid.
Questions about this list
Which public key infrastructure software is ranked first on Freedom251?
OpenCA PKI is ranked #1 of 25 with a score of 6.5. step-ca is second and OpenXPKI third.
How many of these have a free plan?
6 of the 25 on this page publish a free plan on their own pricing pages.
Which is the cheapest paid option?
On this page, Microsoft Cloud PKI has the lowest first paid tier we found: $2/mo.
How is this list ranked?
Ranked free-and-open first: a usable free tier and open-source code, then the platforms it runs on and its documentation.