Updated September 29, 2026 · ShieldCue Editorial Team
OnlyKey vs Thetis
OnlyKey vs Thetis: the differences
| Compare | OnlyKey ReviewSee alternativesSee alternatives |  Thetis |
|---|---|---|
| Price | €49.95 | $24.99 to $49.99 |
| Protocols | Fido2, U2f, Otp | Fido2, U2f, Otp, PivCovers more |
| Connectors | USB a, USB c | USB a, USB c, NFCCovers more |
| Biometric unlock | No | YesHas it |
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Key differences
- Thetis scores higher overall: 9.3 vs 8.2.
- Protocols: only Thetis offers Piv.
- Connectors: only Thetis offers NFC.
- Biometric unlock: only Thetis.
- Support channels: only OnlyKey offers Community.
- Founded is lower at Thetis: 2014 vs 2016.
Our verdict on each
OnlyKey
OnlyKey suits buyers who want a hardware key that handles passkeys, TOTP codes and password storage together, with open source firmware and a logging policy that keeps customer secrets off the vendor's side. The Duo costs €49.95 as a device, above Token2 and the Google Titan Security Key.
Thetis
Thetis suits anyone who wants a hardware key with the full protocol set and a broad connector choice at a budget price, plus the option of keeping a spare. Budget keys run $24.99 to $49.99, which starts at the cheaper end and leaves room for a backup.
Score breakdown
| Area | OnlyKey | Thetis |
|---|---|---|
| Cost | 8.0The Duo costs €49.95 and ranks 14 of 15 on price across the site. | 9.7Higher |
| Offer | 8.6 | 9.2Higher |
| Privacy | 8.0 | 8.8Higher |
What each covers
| Protocols | OnlyKey | Thetis |
|---|---|---|
| Fido2 | Yes | Yes |
| U2f | Yes | Yes |
| Otp | Yes | Yes |
| Piv | No | Yes |
| Connectors | OnlyKey | Thetis |
|---|---|---|
| USB a | Yes | Yes |
| USB c | Yes | Yes |
| NFC | No | Yes |
How they place
| Ranking | OnlyKey | Thetis |
|---|---|---|
| Hardware security keys | 8 of 18 | 2 of 18 |
Every fact side by side
| Fact | OnlyKey | Thetis |
|---|---|---|
| Pricing model | Not confirmed | Budget |
| Legal entity | CryptoTrust LLC | Razzo Tech Corporation DBA Thetis.io |
| Headquarters | United States | United States |
| Founded | 2016 | 2014Lower |
| Support channels | Email, Help centre, CommunityCovers more | Email, Help centre |
Privacy tools
| Fact | OnlyKey | Thetis |
|---|---|---|
| Price from | €49.95 | Not confirmed |
| Free plan | No | Not confirmed |
| Platforms | Windows, MacOS, Android, Linux, Chrome OS | Not confirmed |
| Logging policy | Zero knowledge: no customer keys or sensitive data stored by the company | Not confirmed |
| Jurisdiction | US | Not confirmed |
| Open source | Yes | Not confirmed |
Password managers
| Fact | OnlyKey | Thetis |
|---|---|---|
| Passkeys | Yes | Not confirmed |
| Encryption | AES-256-GCM, PIN protected with wipe after 10 failed unlock attempts | Not confirmed |
| Features | TOTP | Not confirmed |
Pros and cons
OnlyKey
Pros
- Open source firmware, paired with a logging policy in which the company states it holds no customer keys or sensitive data.
- The Duo carries usb a and usb c in the same unit, so machines with either port are covered by the same purchase.
- It speaks fido2, u2f and otp and also handles totp codes, so the same key covers security keys, authenticator codes and passwords.
Cons
- Biometric unlock is no, which leaves the PIN and its wipe rule carrying the security of the device.
- The free plan is no, so the only route to the features is buying hardware at €49.95.
- The price runs above Token2 at €7 to €37 and the Google Titan Security Key at $30 to $35.
Thetis
Pros
- The protocol list is fido2, u2f and otp, covering FIDO2 alongside the older U2F, OTP and PIV standards on the same device.
- Biometric unlock is standard, so a fingerprint replaces a typed password on the services that offer it.
- Connectors come in usb a, usb c and nfc, so the same key suits a desktop, a laptop and a phone.
Cons
- Support runs on email and help centre only, so a buyer whose key fails on a work laptop reaches a mailbox rather than a voice.
- The top of $24.99 to $49.99 runs above Google Titan Security Key at $30 to $35 and above the SoloKeys Solo 2 at $35, so the range is not the cheapest choice for every reader.
- Token2 lists €7 to €37, which starts under the Thetis range, though that quote sits in a different currency to $24.99 to $49.99.
Who each suits
OnlyKey
Who it suits
- People who want a physical key for passkeys and authenticator codes and who treat open source firmware as a requirement rather than a bonus.
- Mixed-port desks that need USB-C and USB-A covered by usb a and usb c in a single purchase.
- Buyers who would rather own the key outright and can accept a PIN instead of biometric unlock.
Who should look elsewhere
- Not for the tightest budget, since Token2 runs €7 to €37 against OnlyKey at €49.95.
- Not for people who expect to pick up a phone, because OnlyKey lists email, help centre and community as its support routes.
Thetis
Who it suits
- First-time hardware key buyers who want biometric unlock without paying the top of the range.
- People running mixed accounts, since fido2, u2f and otp covers current sign-in and the protocols older services still ask for.
- Households and small teams that need a device to cover a desktop, a laptop and a phone, given usb a, usb c and nfc.
Who should look elsewhere
- SoloKeys Solo 2, if a fixed $35 suits the budget better than the $24.99 to $49.99 range.
- Token2, if a lower starting price matters more than biometric unlock, since €7 to €37 opens below the budget range.
- Google Titan Security Key, if a tighter price band works better, at $30 to $35.
Questions about each
OnlyKey
What does an OnlyKey cost, and what do rivals charge?+
The Duo is priced at €49.95, and entry prices start at €49.95. The figure buys the hardware, so the outlay at entry is the outlay later on, and the device price is the only price on offer here. Cheaper rivals exist: Token2 runs €7 to €37 and the Google Titan Security Key runs $30 to $35.
Which protocols and passkey methods does it support?+
The protocol list is fido2, u2f and otp, and passkeys are supported as well. That lets the same device act as a passkey authenticator, a security key for a login prompt and an OTP token for codes. Password storage sits on the key too, so a login, a code and a saved credential are handled by the same purchase rather than by separate tools.
Thetis
How much does a Thetis security key cost?+
Thetis budget keys sit at $24.99 to $49.99, against a group median of €30.69 for the security keys compared here. The range starts at the cheaper end of the field and climbs past the €46.24 that covers most of the group, so the model suits a first key or a pair rather than a top-end purchase.
Do Thetis keys come with a subscription or a renewal price?+
Thetis keys are hardware, so $24.99 to $49.99 is the purchase figure for the budget model rather than a rate with a term attached. Readers who dislike a recurring charge have nothing to cancel and nothing to reprice at renewal, which is the clearest difference between a device like this and a service. The only repeat cost is buying a spare.