BitBox02 Bitcoin-only vs Coldcard Mk4: Best Bitcoin Hardware Wallet in 2025?

BitBox02 Bitcoin-only and the Coldcard Mk4 are both excellent Bitcoin hardware wallets with distinct approaches—BitBox02 emphasizes simplicity and user-friendliness, while Coldcard excels in robust, advanced security features.

Quick Decision Guide

Here's a quick overview of which wallet might be best for your specific needs:

BitBox02 Bitcoin-only

Best For:

• Users seeking simple setup and an intuitive, guided experience via the BitBoxApp
• Want a compact, minimalist design with easy microSD backup

Coldcard Mk4

Best For:

• Power users wanting robust, air-gapped security
• Advanced workflows (PSBTs, multiple PINs)
• Flexible multisig and multiple seeds on one device

BitBox02

Designed with a minimalist approach, the BitBox02 focuses on ease of use and straightforward onboarding. Its compact form factor and intuitive BitBoxApp integration make it beginner-friendly, while retaining advanced features like passphrase protection and multisig support.

Coldcard Mk4

Coldcard’s design philosophy prioritizes robust security measures. From the specialized keypad to air-gapping via microSD or NFC, it caters to users who want maximum control over transaction signing and wallet configuration. Although it’s more complex to set up and operate, experienced users appreciate the in-depth features like duress wallets, full PSBT workflows, and strong anti-tampering checks.

BitBox02

Emphasizes open security. Its firmware, app, and hardware schematics are open-source and publicly auditable. The device uses a dual-chip architecture – a general microcontroller plus a secure element chip (ATECC608B) – to store secrets and prevent tampering.

However, the BitBox02 is not air-gapped; it must connect via USB to sign transactions (no option for offline signing by design). It lacks specialized on-device anti-phishing cues like login words, but its simplicity (and tamper-evident packaging) provides basic phishing and tampering protection.

You will rely on the trusted BitBoxApp, which can use Tor for privacy, and verify addresses on the BitBox02’s screen to avoid man-in-the-middle attacks. Overall, the security philosophy is transparency (open-source code) combined with a secure chip to resist physical hacks.

Coldcard Mk4

Built for maximal security, its code is source-available (users can inspect firmware code) but not fully FOSS in licensing. Uniquely, the Mk4 contains two secure element chips from different manufacturers (Microchip ATECC608C and Maxim DS28C36B) to store your seed, alongside a secure MCU. This dual-SE design means an attacker would need to compromise two independent hardware secrets plus the main processor – dramatically reducing single points of failure.

The Coldcard is designed for true offline use: it supports air-gapped workflows via microSD card or NFC, so you can sign transactions without ever plugging the device into an online computer. When you do use a PIN to unlock, the Coldcard shows two unique anti-phishing words on its screen after entering the first PIN half, which the user must recognize to ensure the device hasn’t been swapped or tampered with. Security features also include duress pins and dummy wallets – you can set a secondary PIN that leads to a decoy wallet, or a “Brick Me” PIN that instantly wipes the device if coerced.

Additionally, the Coldcard’s firmware is signed by the factory; on boot it verifies the signature and lights a green LED if firmware is genuine (or a red warning LED if something is off). All these layers – dual secure elements, air-gap capability, anti-phishing checks, and trick PINs – make the Mk4 exceedingly robust against both remote and physical attacks, albeit with added complexity in use.

Both wallets are BTC only. Shift Crypto sells two firmware editions – a dedicated Bitbox02 Bitcoin-only version and a separate “Multi” edition for altcoins. The Bitcoin-only firmware cannot be switched to support other coins (it’s locked at factory). If a user later needs altcoin support, they’d have to buy the Multi edition device or flash the multi-coin firmware, but out-of-the-box the Bitcoin-only BitBox02 keeps it strictly BTC.

Coldcard has never supported altcoins; it’s dedicated entirely to BTC signing.

Both wallets use standard BIP-39 recovery seeds, but they handle backups differently.

BitBox02

During setup, the device generates a 24-word seed (by default) and automatically saves an encrypted backup to the included microSD card. This is a user-friendly touch: you get an instant, plug-and-play backup without needing to write down the words if you don’t want to. (You can optionally view the seed phrases on screen to copy it to paper as an extra backup, which Shift Crypto encourages as a secondary method.)

BitBox02 does not support multiple simultaneous seed storages – it holds one seed at a time (though you can wipe and restore as needed). It supports BIP-39 passphrases (25th word) for an extra layer – you enter the passphrase via the BitBoxApp or mobile app, and the device will derive a completely separate wallet (the passphrase never leaves the device’s secure chip). This allows advanced users to create hidden accounts.

Backup-wise, the primary method is the microSD card file; the BitBoxApp will remind you to keep that card safe (and you can make additional copies). There isn’t a special Shamir sharing or seed-splitting feature – the philosophy is simplicity: either use the SD card backup or your written mnemonic.

Coldcard Mk4

Setup on a Coldcard yields a 24-word seed by default (12-word optional) which you must write down; Coldcard will not automatically save it for you. However, it offers powerful backup options after setup. Notably, you can create an encrypted backup file on microSD – Coldcard will encrypt your seed with a passphrase you choose and save it to the SD card.

This file can be stored as a digital backup and later restored on any Coldcard with the passphrase. The Mk4 also introduced a “Seed Vault” feature to store multiple seeds: you can have multiple wallets (seeds) on one Coldcard, switching between them using different PIN prefixes or via the Secure Element memory. This is useful for managing multiple accounts (e.g. business vs personal) or decoy seeds.

BitBox02 relies on external wallet applications like Electrum, Specter Desktop, and Sparrow Wallet to configure and manage multisig wallets. It can register up to 25 unique multisig setups, storing essential information such as extended public keys (xpubs) of co-signers, which facilitates verification processes.

Coldcard Mk4 offers native support for multisig wallets. Users can define multisig wallets directly on the device by importing configuration files via microSD card, NFC, or QR codes. The device stores details like the number of co-signers (N), required approvals (M), xpubs, extended fingerprints (XFPs), address formats, derivation paths, and wallet names.

BitBox02

BitBox02 connects via USB-C to the BitBoxApp, providing a direct, straightforward signing experience. There’s no built-in air-gap option, so all transactions must be signed while the device is plugged in. BitBoxApp can route over Tor for enhanced privacy. For most users, this USB-only workflow is fast and simple, with on-screen address verification serving as a final safeguard against man-in-the-middle threats.

Coldcard Mk4

Coldcard stands out for its offline signing capabilities. While you can connect over USB if needed, the recommended method is signing PSBTs via microSD card or NFC. This air-gapped approach ensures that your private keys never interact with an online machine, drastically reducing remote attack vectors. Although this workflow can be more involved – requiring extra steps to move transaction files back and forth – it appeals to security-conscious users who value the lowest possible risk exposure.

BitBox02

Sleek and compact, BitBox02 looks more like a small USB dongle. It has a single USB-C port, no external keypad, and a simple OLED screen. The touch sensors on the side of the device handle confirmations (such as tapping or holding for various inputs). Its low-profile shape and minimal branding help it blend in and remain discreet if carried around or stored in a home office.

The BitBox02’s interface revolves around its small screen and capacitive touch sliders. Users confirm addresses, PINs, and menu selections by touching or swiping the device edges. The OLED display is crisp, but limited in text space; navigation is primarily guided by the BitBoxApp on your computer or smartphone. This minimalism suits those who prefer a less cluttered setup, yet it might feel restrictive for users who want to manage everything entirely from the hardware wallet’s screen.

Coldcard Mk4

By contrast, the Coldcard Mk4 has a more utilitarian design: a robust plastic case, a numeric keypad, and a larger screen that displays multiple lines of text. The keypad facilitates PIN entry and menu navigation directly on the device, reinforcing its self-contained, offline philosophy. Its transparent case reveals internal circuitry – and the LED indicators (green/red) provide clear cues about firmware authenticity at boot time.

A larger screen and physical buttons make the Coldcard’s interface more granular – you can scroll through addresses, check transaction details, and confirm each step on-device without relying heavily on a companion app. The numeric keypad streamlines PIN entry and offers advanced menu functions for tasks like setting duress wallets or toggling specialized security features. While it may have a steeper learning curve, power users appreciate the robust functionality and autonomy that the Coldcard interface provides.

BitBox02

BitBoxApp is the official companion software, giving users a polished and user-friendly interface for managing their wallets. It supports easy firmware updates, transaction history, and additional security settings like passphrase entry. Beyond the official app, the BitBox02 integrates with popular Bitcoin software (Electrum, Sparrow, etc.) for those who prefer a more customizable setup or need multisig functionality. .

Coldcard Mk4

Coldcard users typically interface with desktop wallets such as Electrum, Sparrow, or Specter for transaction creation and signing (often via PSBT files). While there’s no official Coldcard “suite” akin to the BitBoxApp, the community and third-party software fill that gap. Coldcard firmware updates and security checks are often managed directly on the device via microSD. The broader ecosystem around PSBT workflows ensures that the Coldcard can integrate into complex setups, including large multisig arrangements, without locking users into proprietary tools.

Final Thoughts

Ultimately, choosing between the two wallets boils down to your technical comfort levels and your specific security requirements. The BitBox02’s streamlined approach and user-friendly BitBoxApp make it an ideal entry point and it still packs important features like BIP-39 passphrases and multisig compatibility. Meanwhile, the Coldcard Mk4 caters to Bitcoiners seeking comprehensive air-gapped protection, multiple PIN options, and advanced PSBT workflows. Both devices are excellent choices to safeguard your private keys; the best wallet is the one you’ll use confidently, ensuring that your Bitcoin remains securely under your control. Happy hodling! 🚀