Disable Passkeys от TheConfax

As of 2026, this is the only way to have granular per-site control over passkey prompts and passkey autofill in Firefox.

This extension disables WebAuthn requests and can be configured to block passkey login, creation, or both. Passkey entries in autofill will be blocked as well.

Disable passkey prompts on every website, or use the filters to whitelist/blacklist specific domains, allowing you to use traditional passwords without interruption.

Source: https://github.com/TheConfax/Disable-Passkeys