YubiKeys are hardware security devices developed by Yubico that provide strong, possession-based authentication for accessing computers, networks, and online services. They are designed to enhance security by using cryptographic keys to verify user identity, making them resistant to phishing and other cyber threats. YubiKeys offer a combination of resilience and convenience, supporting multiple authentication protocols such as FIDO2/U2F for passwordless authentication, OTPs for generating single-use codes, and passkeys for cross-device authentication. Unlike passkeys stored on cloud services, those on YubiKeys are device-bound, enhancing security. Compared to authenticator apps, YubiKeys are more durable, isolated from vulnerable software environments, and do not require power, making them highly reliable. They are used across various industries, including remote workforces and high-security government sectors, due to their robust protection against cyber threats, ease of use, and durability. For developers looking to integrate YubiKey authentication, platforms like Descope provide tools to simplify the process, offering flexible solutions for implementing both passkey and OTP-based security.