Bitcoin Multisig Comparison: Unchained vs Casa vs Nunchuk vs Sparrow

Bitcoin Multisig Solutions Compared

Bitcoin multisig (multi-signature) wallets require multiple private keys to authorize a transaction, eliminating the single point of failure that comes with standard single-key self-custody. A 2-of-3 setup, for example, means any two out of three keys must sign before funds can move. If one key is lost, stolen, or destroyed, the remaining two can still recover the bitcoin.

The market for multisig tooling ranges from fully managed commercial services like Unchained and Casa to open-source coordinators like Sparrow and Caravan. Each approach makes different tradeoffs between convenience, cost, privacy, and trust. This guide compares the major options across the dimensions that matter most: pricing, key holder structure, inheritance planning, hardware wallet support, and recovery process.

For background on how multisig works at the protocol level, see our research article on Bitcoin multisig wallets explained. To plan your own quorum configuration, try the multisig planner tool.

Overview: Pricing and Feature Snapshot

The following table summarizes the six most common approaches to Bitcoin multisig, from managed commercial vaults to fully DIY setups using Bitcoin Core.

Commercial Multisig Services

Unchained

Unchained offers a collaborative custody model where you hold two signing devices and Unchained holds a third key as a backup co-signer. Since you control two of three keys, you can always withdraw funds independently without Unchained needing to approve or co-sign. Unchained's key exists solely for recovery scenarios.

The entry-level product is a personal vault at $250 per year. The Signature plan ($6,000 first year, $4,500/year renewal) adds concierge onboarding, multi-vault management, and 5-key vault configurations. Unchained also offers Bitcoin IRAs ($250/year), trading at a 1.0% flat fee, and Premium Service Suites ($1,650 to $3,400 one-time) that bundle onboarding, two hardware wallets, and the first year of vault service.

Unchained supports Trezor, Ledger, Coldcard, BitBox, and Blockstream Jade. Their Inheritance Protocol provides step-by-step documentation enabling non-technical heirs or executors to recover bitcoin, and it integrates with trust structures and transfer-on-death beneficiaries.

Casa

Casa takes a mobile-first approach to multisig. On the Standard plan ($250/year), you get a 3-key vault (2-of-3) where the keys are distributed across your phone (mobile key), a hardware wallet (hardware key), and Casa's recovery server. The Premium plan ($2,100/year) upgrades to a 5-key vault (3-of-5) with keys distributed across multiple devices and locations.

Casa supports a wide range of signing devices: Coldcard (Mk3 through Q), Ledger (Nano S, Nano S+, Nano X, Flex, Stax), Trezor (One, Safe 3, Safe 5, Model T), Keystone Pro 2, Foundation Passport, and even YubiKey 5C NFC.

Inheritance is included on all plans. Casa uses a 6-month claim process: the designated recipient requests access, the account holder is notified and can reject the claim, and after 6 months of inactivity the recipient gains access to the mobile key plus Casa's recovery key. Premium adds 1-on-1 inheritance onboarding, while Private Client includes a 75-minute attorney consultation.

Nunchuk

Nunchuk bridges the gap between commercial services and open-source tools. The free tier provides full DIY multisig wallet creation and management with no restrictions on quorum size. The Iron Hand plan ($120/year) adds Nunchuk as an assisted co-signer in a 2-of-3 setup where you hold two hardware keys and Nunchuk holds one platform key.

Higher tiers expand key distribution: Honey Badger ($480/year) offers 2-of-4 with a dedicated inheritance key, and Honey Badger Premier ($2,100/year) provides 3-of-5 with two inheritance keys. Nunchuk supports the broadest range of hardware: TAPSIGNER, Coldcard, Blockstream Jade, TwentyTwo Portal, SeedSigner, Trezor, Ledger, BitBox02, Foundation Passport, and Keystone, with connection methods spanning NFC, USB, QR code, and MicroSD.

Nunchuk's inheritance system is distinctive: it supports both autonomous mode (on-chain timelocks via Miniscript, requiring no trust in Nunchuk) and flexible mode (off-chain timelocks coordinated through the Nunchuk platform). The autonomous option is especially powerful for users who want trustless inheritance without relying on any third party.

Open-Source Multisig Coordinators

Sparrow Wallet

Sparrow is a desktop-only Bitcoin wallet focused on power users. It is completely free, open source (Apache 2 license), and supports any M-of-N multisig configuration. Sparrow does not hold any keys, provide custodial services, or offer inheritance planning. It is a coordinator: you supply the keys, Sparrow handles wallet creation, UTXO management, and transaction construction.

Sparrow was built around the PSBT (Partially Signed Bitcoin Transaction) standard. PSBTs can be created, inspected, edited, saved, and shared via file, QR code, or clipboard. Sparrow supports both air-gapped signing (SD card, QR via UR standard) and USB-connected hardware wallets including Coldcard, Trezor, Ledger, BitBox02, Foundation Passport, SeedSigner, Blockstream Jade, and Keystone.

Additional features include advanced coin control with multiple UTXO selection algorithms (Branch and Bound, Knapsack), Whirlpool coinjoin integration, transaction visualization, connection to your own Bitcoin node or Electrum server, and Tor support. Sparrow runs on Windows, macOS (Intel and Apple Silicon), and Linux.

Caravan

Caravan is Unchained's open-source multisig coordinator, available under the MIT license. It runs entirely in the browser and is stateless: it does not store wallet data between sessions. Users must manage their own wallet configuration files and backups.

Caravan supports up to 7 keys with adjustable quorum thresholds and includes the first open-source PSBTv2 implementation via the @caravan/psbt package. It supports Ledger, Trezor, Coldcard, and BitBox02 directly, with air-gapped device support (SeedSigner, Passport) added via BCURv2 QR codes. Caravan is the free tool that Unchained's commercial platform is built on: it provides the signing infrastructure without the managed key, financial services, or customer support.

DIY with Bitcoin Core

Bitcoin Core natively supports PSBT creation, signing, combining, and finalizing via CLI commands. You can build any M-of-N multisig wallet using output descriptors and Miniscript. This approach offers maximum control and zero third-party trust.

The tradeoffs are significant: you need deep familiarity with Bitcoin scripting and key management, there is no guided setup or health checks, hardware wallet integration is manual, and a single configuration mistake can make funds unrecoverable. You must also run a full node (500+ GB of blockchain data). DIY multisig is best suited to experienced developers who want full sovereignty over every aspect of their setup.

Key Holder Structure Compared

Who holds the keys determines the trust model of your multisig setup. The following table breaks down key distribution across solutions. For a deeper look at threshold signature schemes and how they compare to on-chain multisig, see our research on FROST threshold signatures.

In every commercial option, the company holds exactly one key and cannot move funds unilaterally. This is a critical property: the company key exists only for recovery assistance. You always retain enough keys to transact independently. For more on custody models, see our research on Bitcoin custody solutions compared.

Hardware Wallet Compatibility

Hardware wallet support determines which cold storage devices you can use with each solution. Broader support means more flexibility in your security architecture.

• Unchained: Trezor, Ledger, Coldcard, BitBox, Blockstream Jade
• Casa: Coldcard, Ledger, Trezor, Keystone Pro 2, Foundation Passport, YubiKey 5C NFC
• Nunchuk: TAPSIGNER, Coldcard, Jade, TwentyTwo Portal, SeedSigner, Trezor, Ledger, BitBox02, Passport, Keystone (NFC, USB, QR, MicroSD)
• Sparrow: Coldcard, Trezor, Ledger, BitBox02, Passport, SeedSigner, Jade, Keystone (USB and air-gapped via UR QR codes)
• Caravan: Ledger, Trezor, Coldcard, BitBox02 + air-gapped via BCURv2

Nunchuk offers the widest hardware wallet support across the most connection methods. Sparrow follows closely with strong air-gapped signing support. For a broader comparison of hardware wallets themselves, see the hardware wallet comparison tool.

Inheritance and Recovery

Inheritance is one of the hardest problems in Bitcoin self-custody. If the primary key holder dies or becomes incapacitated, heirs need a reliable way to access funds without the key holder's active participation. Each solution approaches this differently.

Unchained provides an Inheritance Protocol with step-by-step documentation designed for non-technical executors. It integrates with trust structures, transfer-on-death designations, and family key access arrangements. This is included in the Signature plan.

Casa uses a time-based claim process: the designated recipient submits a request, and if the account holder does not reject it within 6 months, the recipient gains access to the mobile key and Casa's recovery key. This provides a built-in dead-man's switch without requiring on-chain timelocks.

Nunchuk offers the most technically sophisticated inheritance system. Autonomous mode uses on-chain timelocks encoded via Miniscript, making inheritance trustless: after a specified period of inactivity, the inheritance key can co-sign without Nunchuk's involvement. This requires Miniscript-compatible hardware (Coldcard, Jade, or Ledger for the inheritance key).

Sparrow, Caravan, and DIY setups offer no built-in inheritance. Users must arrange their own inheritance planning, which typically involves distributing seed phrases and wallet descriptors to trusted parties or placing them in geographically separated secure locations. For an overview of spending policy options, see our research on Miniscript spending policies.

How to Choose a Multisig Solution

The right multisig setup depends on your technical comfort, the amount of bitcoin you are securing, and how much you value convenience versus sovereignty.

If you want a guided experience with minimal technical overhead: Casa is the most beginner-friendly option. The mobile app walks you through setup, health checks, and key rotation. The 6-month inheritance claim is simple to explain to family members.

If you want strong inheritance planning and financial services: Unchained combines collaborative custody with Bitcoin IRAs, trading, and a detailed Inheritance Protocol designed for estate planners.

If you want the best of both worlds (assisted + open source): Nunchuk offers a free DIY tier, paid assisted tiers with trustless on-chain inheritance, and open-source code (GPLv3). It is the most flexible option for users who may start with DIY and later want professional co-signing.

If you are a power user who wants full control: Sparrow provides the deepest feature set for UTXO management, coin control, privacy (coinjoin), and PSBT workflows. You handle all key management yourself.

If you are a developer building or testing multisig workflows: Caravan is ideal for prototyping and verifying setups in the browser. Bitcoin Core is the reference implementation for CLI-based multisig.

PSBT Workflow Support

PSBT (Partially Signed Bitcoin Transaction, BIP 174) is the standard format for constructing and signing multisig transactions across multiple devices. All six solutions support PSBT, but the depth of support varies.

Sparrow and Caravan offer the most advanced PSBT tooling. Sparrow uses PSBTv2 as its default internal representation and supports BIP375 PSBT fields. Caravan includes the first open-source PSBTv2 implementation. Nunchuk was built around PSBTs and the descriptor language from the start. Unchained and Casa support PSBT signing through their respective apps, with Unchained leveraging the same Caravan PSBT libraries under the hood. Bitcoin Core supports PSBT natively via CLI commands.

To inspect and debug PSBTs directly, use the PSBT inspector tool.

Frequently Asked Questions

What is the cheapest Bitcoin multisig setup?

Sparrow, Caravan, and Nunchuk (free tier) all offer free multisig wallet creation. Sparrow and Nunchuk are the most practical free options: Sparrow provides a full desktop wallet with advanced UTXO management, while Nunchuk provides cross-platform support including mobile. Caravan is free but stateless, meaning it does not persist wallet data. The total cost also includes hardware wallets: budget at least $60 to $150 per signing device, and a 2-of-3 setup requires at minimum two devices.

Is multisig better than a single hardware wallet?

Multisig eliminates single points of failure. With a single hardware wallet, losing the device and its seed phrase backup means permanent loss of funds. A compromised seed phrase means theft. Multisig distributes risk: an attacker needs to compromise multiple keys stored in separate locations. The tradeoff is complexity, as multisig requires managing multiple devices, backups, and wallet descriptors. For holdings above a personal threshold (often cited as 0.5 to 1 BTC), the added security of multisig is generally worth the operational overhead.

Can I recover funds if the multisig company shuts down?

Yes, for all commercial solutions listed here. In Unchained's 2-of-3 model, you hold 2 keys and can withdraw independently at any time. In Casa's 2-of-3, you hold the mobile key and hardware key, which is sufficient. In Nunchuk's assisted tiers, you hold enough keys to meet the quorum without the platform key. The critical step is ensuring you have a backup of your wallet descriptor (the xpub information and derivation paths for all keys in the quorum). Without the descriptor, recovering a multisig wallet from seed phrases alone is extremely difficult.

What hardware wallets work best for multisig?

Coldcard is the most universally supported across all multisig solutions and offers native multisig features including PSBT signing via MicroSD for fully air-gapped operation. Trezor and Ledger are supported by all commercial services. For budget-conscious setups, SeedSigner (a DIY signing device built on a Raspberry Pi Zero) works with Sparrow and Nunchuk via QR codes. Foundation Passport and Blockstream Jade are strong mid-range options with broad compatibility.

How does multisig inheritance work?

Commercial services offer structured inheritance. Casa uses a 6-month inactivity-based claim process. Unchained provides detailed documentation for executors through its Inheritance Protocol. Nunchuk offers on-chain timelocked inheritance via Miniscript, which is the most trustless option: after a defined period of inactivity, the inheritance key gains signing authority automatically, with no reliance on any third party. For DIY setups, inheritance planning requires manual distribution of seed phrases and descriptors to trusted parties, often using a combination of safety deposit boxes and sealed envelopes with instructions.

What is the difference between multisig and MPC wallets?

On-chain multisig uses Bitcoin's native scripting to require multiple signatures, making the quorum enforced by the blockchain itself. MPC wallets use cryptographic key-splitting so that multiple parties each hold a share of a single private key, and they collaboratively produce one standard signature. Multisig is transparent on-chain (the spending conditions are visible in the script), while MPC produces a single-signature transaction that looks like any other. MPC can be cheaper in transaction fees but introduces cryptographic protocol complexity and is not natively enforced by Bitcoin consensus. For related threshold approaches, see our research on MuSig2 multisignatures.

Do I need to run a full Bitcoin node for multisig?

Only for DIY Bitcoin Core multisig. Sparrow can connect to your own node or a public Electrum server. Caravan can use a public block explorer or your own node. Commercial services (Unchained, Casa, Nunchuk) run their own infrastructure so you do not need a node. Running your own node improves privacy and trustlessness by verifying transactions locally rather than relying on third-party servers.

This tool is for informational purposes only and does not constitute financial advice. Pricing, features, and availability are based on publicly available information and may change. Always verify current details on each provider's website before making custody decisions.