Full (strict)

When you set your encryption mode to Full (strict), Cloudflare does everything in Full mode but also enforces more stringent requirements for origin certificates.

flowchart LR
    accTitle: Full - Strict SSL/TLS Encryption
    accDescr: With an encryption mode of Full (strict), your application encrypts traffic going to and coming from Cloudflare.
    A[Browser] <--Encrypted--> B((Cloudflare))<--Encrypted--> C[("Origin server (verified) #9989;")]

Use when

For the best security, choose Full (strict) mode whenever possible (unless you are an Enterprise customer).

Your origin needs to be able to support an SSL certificate that is:

• Unexpired, meaning the certificate presents notBeforeDate < now() < notAfterDate.
• Issued by a publicly trusted certificate authority ↗ or Cloudflare’s Origin CA.
• Contains a Common Name (CN) or Subject Alternative Name (SAN) that matches the requested or target hostname.

Note

In addition to Full (strict) encryption, you can also set up Authenticated Origin Pulls to ensure all requests to your origin are evaluated before receiving a response.

Required setup

Prerequisites

Before enabling Full (strict) mode, make sure your origin:

• Allows HTTPS connections on port 443.
• Presents a certificate matching the requirements above.

Otherwise, your visitors may experience a 526 error.

Process

Dashboard

To change your encryption mode in the dashboard:

1. Log in to the Cloudflare dashboard ↗ and select your account and domain.
2. Go to SSL/TLS.
3. Choose an encryption mode.

API

To adjust your encryption mode with the API, send a PATCH request with ssl as the setting name in the URI path, and the value parameter set to your desired setting (off, flexible, full, strict).

Limitations

Depending on your origin configuration, you may have to adjust settings to avoid Mixed Content errors or redirect loops.