Foundation Passport vs Coldcard Mk4: Which Air-Gapped Bitcoin Wallet Wins? (2026)

Foundation Passport vs Coldcard Mk4: two of the most serious Bitcoin hardware wallets available. Both are air-gapped (no USB required for signing), both are built specifically for Bitcoin, and both attract users who have graduated past beginner hardware wallets. The difference is in philosophy and execution: Passport is fully open source and built for human beings; Coldcard is a fortress of cryptographic security that rewards patience.

Here is the direct comparison.

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At a Glance

Feature	Foundation Passport	Coldcard Mk4
Price	$199 (Passport 2) / $99 (Passport Core)	$157
Air-gap method	QR codes (camera)	microSD (PSBT files)
Open source	Fully (hardware + firmware)	Firmware only
Made in USA	Yes	No (Canada)
Secure element	Yes (ATECC608)	Yes (dual: ATECC608A + SE050C)
Screen	Large color touchscreen	Small monochrome OLED
Connection	USB-C (power only), QR, microSD	USB-C, NFC, microSD
Battery	Yes (rechargeable)	No (USB power only)
Companion app	Envoy (mobile)	No official app (use Sparrow)
Bitcoin-only firmware	Yes (default)	Yes (always BTC only)
Multisig support	Yes (Sparrow, Envoy)	Yes (Sparrow)
Difficulty level	Intermediate	Advanced
Passphrase support	Yes	Yes

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Foundation Passport

Foundation Devices (/cold-storage/foundation-passport) built the Passport with a single priority: maximum transparency. The Passport 2 is the first major hardware wallet to be fully open source — not just the firmware, but also the hardware schematics and PCB layout. Anyone can audit every component.

The QR Air-Gap Advantage

Passport signs transactions via QR codes. The workflow:

1. Create an unsigned transaction in Sparrow Wallet or Envoy app
2. The app displays a QR code representing the PSBT (Partially Signed Bitcoin Transaction)
3. Passport's camera scans the QR code
4. Passport signs the transaction internally
5. Passport displays a new QR code with the signed transaction
6. Sparrow scans the signed QR and broadcasts to the network

At no point does any data transfer via physical connection. The Passport camera is the only input. This makes it impossible for malware on your computer to interact with the device through a data channel — there is no data channel.

The Envoy App

Foundation's Envoy mobile app is genuinely excellent for a hardware wallet companion — clean UI, clear transaction verification, and step-by-step guidance for new Passport users. You can manage your wallet on your phone via Envoy while keeping the Passport in a drawer. Signing still requires the physical device.

For users who prefer desktop, Passport integrates fully with Sparrow Wallet.

Open Source Philosophy

The source code for Passport's firmware is on GitHub. The hardware schematics are also published. This means the security community can (and does) audit Foundation's work. For users who consider trust minimization a core value, Passport offers something Coldcard does not: complete verifiability.

Passport Core

Foundation also offers Passport Core (/cold-storage/passport-core) at $99 — a smaller, lighter version with the same open-source firmware and QR air-gap capability, but without the color touchscreen. For users who want the Passport philosophy at a lower price point, Core is worth considering.

Passport Limitations

• QR signing requires your phone or computer camera to be working reliably. Poor lighting or camera degradation can disrupt the workflow.
• Less battle-tested than Coldcard — Foundation is a newer company.
• The $199 price is higher than Coldcard for most users' needs.

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Coldcard Mk4

Coldcard Mk4 (/cold-storage/coldcard-mk4) from Coinkite is the most feature-rich hardware wallet available. It has been around since 2018 and has earned its reputation as the paranoid Bitcoin holder's tool of choice.

Dual Secure Elements

Coldcard Mk4 uses two separate secure elements from different manufacturers (ATECC608A from Microchip and SE050C from NXP). This is unique in the hardware wallet market. The idea: if one secure element manufacturer is compromised or coerced, the attacker still cannot access your keys without also compromising the second. The design distributes trust across two independent supply chains.

The microSD Air-Gap Workflow

Coldcard signs transactions via microSD cards (PSBT files). The workflow:

1. Create an unsigned PSBT in Sparrow Wallet
2. Export to microSD card
3. Insert microSD into Coldcard
4. Review and sign on Coldcard
5. Remove microSD, insert into computer
6. Sparrow reads signed PSBT and broadcasts

This requires a dedicated microSD card and the physical process of moving it between devices. It is more friction than QR signing but some users prefer it — there is nothing wireless, and the data format is a standard file you can inspect.

Security Features No Other Wallet Has

• Brick-me PIN: a special PIN that irreversibly destroys the secure element if entered. For situations where you are forced to hand over your PIN.
• Duress wallets: set up a secondary wallet with a small amount of Bitcoin that opens under a different PIN — if coerced, hand over the duress PIN
• Login countdown: configure a waiting period before the device unlocks, even after a correct PIN
• Anti-phishing words: two words displayed after entering the first portion of your PIN confirm you are on your real device, not a spoofed interface
• NFC: sign via NFC tap on supported wallets (optional, can be disabled)

PSBT Standard (Bitcoin Protocol Native)

Coldcard was an early pioneer of PSBT (BIP174) signing — the standard format for partially signed transactions now used across the Bitcoin ecosystem. If you are building advanced setups involving multiple signers or third-party coordinators, Coldcard's adherence to Bitcoin standards is a practical advantage.

Coldcard Limitations

• Interface is intentionally minimal — small monochrome screen, numeric keypad. The UX is functional but not friendly. Plan to read the documentation.
• No official companion software — use Sparrow Wallet (excellent, but requires setup).
• The microSD workflow requires managing physical media that most users do not otherwise use.
• Not open-source hardware schematics (firmware only).

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Head-to-Head Analysis

Security Architecture

Coldcard wins on depth of security features. Dual secure elements, brick-me PIN, duress wallets, and login countdown give paranoid users tools that Passport does not offer. For threat models involving physical coercion or sophisticated supply chain attacks, Coldcard's architecture is more comprehensive.

Passport's single secure element and open-source hardware is excellent security for typical users — the transparency of auditable hardware is a meaningful counterargument to Coldcard's closed hardware.

Verdict: Coldcard for adversarial threat models; Passport for audit-focused security.

Air-Gap Usability

Passport wins. QR signing is genuinely easier than microSD signing for regular use. No physical media to manage, works from your phone, and the scanning experience is fast once you learn it. For people who sign transactions weekly or monthly, the QR workflow reduces friction considerably.

The microSD approach is reliable and secure, but it requires having a microSD card, a reader, and the patience to move files between devices.

Verdict: Passport for usability; Coldcard for users who prefer physical media.

Open Source

Passport wins decisively. Foundation publishes both hardware schematics and firmware. Coldcard publishes firmware only. For users who consider "don't trust, verify" to be a first principle, Passport is the only option in this comparison that can be fully verified.

Verdict: Passport for maximum transparency.

Beginner Friendliness

Passport wins. The color screen, the Envoy app, and the QR workflow are noticeably more accessible than Coldcard's numeric keypad and documentation-required setup. Neither is truly beginner hardware — both require some learning — but Passport has the shorter on-ramp.

Verdict: Passport for new-to-advanced users; Coldcard for dedicated learners.

Price

Coldcard wins at $157 vs Passport's $199. The Passport Core at $99 changes the equation — Core brings open-source firmware and QR air-gap at a lower price than Coldcard, but sacrifices the color screen.

Verdict: Coldcard vs Passport 2 — Coldcard is cheaper. Passport Core at $99 changes the comparison.

Ecosystem

Coldcard wins on ecosystem depth. Coldcard has been around since 2018 and has the broadest support of any hardware wallet among advanced Bitcoin software tools, coordinators, and third-party integrations. Passport works well with Sparrow and Envoy but has a shorter track record and less community tooling.

Verdict: Coldcard for ecosystem maturity.

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Who Should Buy Each

Buy the Foundation Passport if:

• You value fully auditable, open-source hardware AND firmware
• You want an air-gapped wallet with a user-friendly QR workflow
• You manage Bitcoin from a mobile phone (Envoy app)
• Open source is a non-negotiable for your threat model
• You are a US buyer who prefers USA-made hardware

Buy the Coldcard Mk4 if:

• You want the deepest security feature set available
• Your threat model includes physical coercion (duress PIN, brick-me PIN)
• You prefer a battle-tested device with years of production history
• You are comfortable with a technical setup process
• You want dual secure elements from separate manufacturers

Consider alternatives if:

• You are a beginner — look at Trezor Safe 3 or Ledger Nano X first
• You want a simpler air-gapped QR device at lower cost — Blockstream Jade at $65 is worth considering (see Blockstream Jade vs Coldcard Mk4)

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FAQ

Does Foundation Passport work with Sparrow Wallet?

Yes. Passport integrates fully with Sparrow for both single-sig and multisig setups via QR codes. Sparrow is the recommended desktop coordinator for Passport users who prefer a desktop workflow over the Envoy mobile app.

Can Coldcard Mk4 do QR signing?

Coldcard Mk4 does not have a camera, so it cannot scan QR codes. It uses microSD for PSBT-based signing. The Coldcard Q (/cold-storage/coldcard-q) model adds a keyboard and QR display capability, but does not have an inbound camera.

Is Foundation Passport truly open source?

Yes. Foundation publishes the firmware source code and hardware schematics on GitHub. The hardware uses commercially available components (not custom ASICs) so the design can be replicated and audited. This is genuinely different from competitors who publish firmware but keep hardware designs proprietary.

Which is better for multisig?

Both work excellently in multisig setups via Sparrow Wallet. For a 2-of-3 setup, many advanced users combine a Coldcard with a Passport and a Trezor — different manufacturers, different supply chains, different firmware codebases. This eliminates any single vendor as a point of failure.

Are there newer versions of these wallets?

Foundation also offers Passport Core ($99) as a more affordable option. Coinkite also makes the Coldcard Q ($249+) with a full QWERTY keyboard. Both Mk4 and Passport 2 remain their manufacturers' primary flagship devices as of 2026.

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The Verdict

For most security-focused Bitcoin holders: Foundation Passport. The combination of fully open-source hardware and firmware, QR air-gap, and the excellent Envoy app makes it the most transparently trustworthy hardware wallet available. The $199 price is justified.

For adversarial threat models: Coldcard Mk4. Dual secure elements, duress PIN, brick-me PIN, and years of battle-testing make it the right choice for users with genuine coercion concerns or who demand maximum cryptographic depth.

You cannot go wrong with either. Both are serious tools for serious Bitcoin holders.

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See also: Blockstream Jade vs Coldcard Mk4 · Coldcard vs Trezor vs BitBox · Best Bitcoin Cold Storage Devices 2026 · Browse all hardware wallets