Solo 2

Solo 2 is a physical security key for people who want phishing-resistant sign-in and passkeys kept under their control. It fits individuals, security professionals, and teams that use services supporting hardware authentication, while the Hacker model targets developers and makers. Its open design and wide standards support are compelling, but recovery requires disciplined backup-key and PIN management.

Overview

Solo 2 supports FIDO2, WebAuthn, and U2F, covering the authentication standards used by many modern account providers. Basic operation needs no driver or companion software, so it can add a hardware factor without another desktop installation. A capacitive sensor with three contact points requires a touch to confirm authentication, adding a deliberate physical check rather than silently approving a sign-in.

The key works with security-key-enabled services such as Google, Microsoft, Facebook, Salesforce, GitHub, Dropbox, and Twitter/X. It stores credentials and passkeys on the physical key, with capacity for approximately 100 passkeys and no cloud copy. That is a good fit for users who prefer local custody of credentials, but it makes loss recovery a responsibility: resetting after a forgotten PIN deletes the stored passkeys, so registering a backup key is a sensible requirement rather than an optional extra.

Key features

• Broad authentication support: FIDO2, WebAuthn, and U2F let one key cover current passkey flows and older security-key deployments.
• Local passkey storage: About 100 passkeys can remain on the device instead of a cloud service. Users gain control and lose cloud-based recovery.
• Open-source licensing: Software is dual licensed under Apache 2.0 and MIT, hardware under CERN-OHL-S, and documentation under CC-BY-SA 4.0. This is particularly relevant to security-conscious teams and developers who value inspectable, reusable components.
• Touch confirmation: The capacitive three-contact sensor makes authentication an intentional physical action, useful when preventing unattended approvals matters.
• Management utility: The solo2-cli tool handles passkeys, firmware updates, PINs, PIV, and OpenPGP settings. A graphical Solo 2 interface is still described as coming soon, so command-line management is the practical option for advanced administration.
• Attestation choices: Standard Solo 2 devices ship with locked firmware and SoloKeys attestation certificates. The Hacker model omits attestation and is unlocked for custom firmware, making it better suited to experimentation than policy-driven enterprise enrollment.

Pricing

Solo 2 is sold as a one-time hardware purchase, with no free plan or trial. The entry option is Solo 2C Security Key at $34, paid once; it uses USB-C and has no NFC, making it the lowest-cost choice for USB-C computers and phones that do not need contactless sign-in.

The Solo 2 USB-A Security Key costs $35, paid once and has USB-A without NFC. The Solo 2 USB-A Hacker is also $35, paid once, with USB-A, no NFC, and firmware unlocked for custom work; choose it for development or research, not when attestation is required.

For contactless use, Solo 2C+ NFC Security Key and Solo 2A+ NFC Security Key each cost $46, paid once, with USB-C or USB-A respectively and NFC support. The premium is justified for compatible mobile workflows; the cheaper models give up NFC rather than authentication standards.

Platforms

Solo 2 is offered across Android, iOS, Linux, macOS, the web, and Windows. The maker also lists Windows, macOS, Linux, Android, ChromeOS, and xBSD as supported operating systems, plus Chrome, Edge, Safari, Brave, and Firefox browsers. NFC authentication on compatible Android and iOS devices is supported by Solo 2+ models, not the standard no-NFC versions.

Who it's for

Everyday users protecting email, social, development, and business accounts get a simple hardware factor with broad service coverage. Enterprise teams can use the standard, attested model when locked firmware and a conventional security-key posture matter. Developers, security researchers, and makers have a more specialized option in the Hacker model because custom firmware is possible, although its lack of attestation rules it out for some controlled deployments.

Pros and cons

Pros

• Standards coverage: FIDO2, WebAuthn, and U2F support reduces the need to maintain separate keys for different account systems.
• Local control: Passkeys stay on the key and are not backed up to cloud services.
• Open hardware and software: Published licenses suit organizations that need an inspectable platform.
• Multiple connectors: USB-A, USB-C, and NFC configurations cover desktops and compatible mobile devices.

Cons

• PIN-reset risk: Forgetting the PIN and resetting the device erases all stored passkeys, so a second registered key is important.
• No graphical manager yet: Advanced key, firmware, and credential administration relies on solo2-cli while the GUI is forthcoming.
• NFC costs more: Contactless models cost 46.00 USD, above the 34.00–35.00 USD wired options.
• Hacker model lacks attestation: Its unlocked firmware is unsuitable where device attestation is part of an access policy.

Alternatives

Security Keys is the broader category to browse when you want to compare other hardware authenticators.

Choose Yubico Authenticator instead if you want free, open-source companion software for Android, iOS, Linux, macOS, and Windows; it requires a YubiKey to store credentials and generate codes.

Deepnet SafeKey is an alternative hardware-key family with Android, iOS, macOS, web, and Windows coverage and quote-based pricing.

SafeNet MobilePASS+ is another paid option for Android, iOS, macOS, and Windows.

Pick Swissbit iShield Key 2 when you need USB-A or USB-C plus NFC and prefer purchasing through a sales partner.

TrustKey T110 is a paid alternative focused on web and Windows support.

FEITIAN ePass FIDO-NFC Security Key costs $35, paid once and combines USB-A or USB-C, NFC, FIDO U2F/FIDO2, and HOTP/TOTP.

Token2 T2F2-NFC-Slim is a paid USB-A alternative with volume pricing and a product-page price of £18.80 in Great Britain.

Choose YubiKey 5 Series instead if you want a paid key family with USB-A, USB-C, and NFC models, including 58.00 USD options.

Verdict

Solo 2 is a strong choice for users and teams seeking an open-source, touch-confirmed key that supports major authentication standards and keeps passkeys local. Its main reason to choose it is the combination of broad compatibility and transparent hardware/software licensing at a one-time price from 34.00 USD. Look elsewhere if you need cloud-style credential recovery, a ready graphical management console, or attestation on an unlocked development key.