How ZeroSSL and Let's Encrypt differ on deployment, pricing, openness and what each is actually built for.
| ZeroSSL | Let's Encrypt | |
|---|---|---|
| Type | Public CA (freemium) | Public CA (free) |
| Deployment | SaaS (ACME) | SaaS (ACME) |
| How it works | Issues DV certificates over ACME like Let’s Encrypt, plus a browser console for teams that would rather click than script. Paid plans from $9.99/month add multi-domain certificates, a management console and support. Owned by HID Global, part of ASSA ABLOY. | Issues domain-validated TLS certificates at no cost, exclusively through the ACME protocol. Short 90-day lifetimes force automation, which is the point: renewal is a cron job, not a calendar reminder. |
| Pricing* | Free tier; paid from $9.99/mo | Free |
| Free tier | Yes | Yes |
| Open source | — | Boulder (MPL-2.0) |
| Compliance | WebTrust, CA/B Forum | WebTrust, CA/B Forum |
| Best for | ACME with a UI and a support path | Public web TLS on anything you can automate |
Choose ZeroSSL for acme with a ui and a support path. Choose Let's Encrypt for public web tls on anything you can automate.
* Indicative list pricing (vendor documentation and public pricing pages, August 2026).