Short answer: in a non-custodial wallet the user holds the keys and the provider cannot move funds, in a custodial wallet the provider holds the keys on the user's behalf, and an MPC wallet splits a key into pieces so that no single device or party holds the whole thing. Each choice moves risk and responsibility around. None removes it.
This comparison is written for founders deciding which wallet design to build or buy. We build wallet software; we do not hold client funds, and the client is responsible for any licence a custodial service may need in its market. For what we build, see crypto wallet development.
What a wallet actually holds
A crypto wallet does not store coins. The coins live on the blockchain. The wallet stores or controls the private key that authorizes moving them. Whoever can use that key controls the funds. So the three wallet types differ in one question: who can use the key, and under what conditions.
Non-custodial wallets
In a non-custodial wallet the key is created and kept on the user's device, often protected by a recovery phrase. Your company never has access to it. This is the model behind most browser extension and mobile wallets.
- Upside: users keep control, you do not carry custody risk, and there is no central pool of funds for an attacker to target.
- Downside: if a user loses the recovery phrase or the device, nobody can restore access, and if a user is tricked into signing a bad transaction, it usually cannot be undone.
- Work for the builder: clear signing screens that show what a transaction does, safe backup flows, device-level protection such as secure enclave storage, and careful handling of connections to dApps.
Non-custodial wallets suit audiences that want self-custody and are comfortable with the responsibility. They need strong user education built into the product, because most support problems come from recovery and scams, not from bugs.
Custodial wallets
In a custodial wallet the provider holds the keys and keeps a record of what each user owns. Users sign in with an email or password, much like a bank app. Exchanges and many payment apps work this way.
- Upside: familiar sign-in, password reset, easier support, and the ability to offer features such as internal transfers without network fees, limits and fraud controls.
- Downside: you become the target. A breach of your key storage can affect every customer at once, and users depend on your honesty and solvency.
- Work for the builder: hot and cold wallet separation, withdrawal approvals, rate limits, monitoring, an auditable ledger, backup and recovery of the key material, and an incident plan.
Holding customer funds is regulated in many countries. Whether you need a licence, a registration or specific capital and reporting rules depends on where you operate and where your users live. That is a question for a lawyer, not a developer.
MPC wallets
Multi-party computation (MPC) wallets split a signing key into shares held by different parties or devices. To sign, the parties run a protocol that produces a valid signature without ever assembling the full key in one place. A common setup gives one share to the user's phone and one to a server, sometimes with a third share held as a backup.
- Upside: no single stolen device or server reveals the key, recovery can be designed without a seed phrase, and policies such as limits or approvals can be enforced during signing.
- Downside: the cryptography is complex and should rely on well-reviewed libraries, the design depends on how shares are stored and refreshed, and signing may need network round trips.
- Work for the builder: choosing a protocol, handling share storage and recovery, designing what happens if the server is down or the phone is lost, and reviewing the whole flow carefully.
It is worth being plain about one point. MPC reduces some risks but does not make a wallet unhackable. Whoever controls enough shares, or the process that approves signing, still controls the funds. Ask exactly who holds each share and what happens if the provider disappears.
Related designs you will hear about
- Smart contract wallets: the account is a contract with rules, such as spending limits, social recovery or batched actions. Support differs by chain and costs more to run on some networks.
- Multi-signature wallets: several separate keys must approve a transaction. Common for company treasuries.
- Embedded wallets: created inside an app so users do not need to install anything. They may be custodial, MPC or non-custodial depending on the provider.
How to choose
Work from your users and your obligations, not from fashion.
- Who are your users, and can they manage their own recovery phrase?
- Do you want, and are you permitted, to hold funds on their behalf?
- What happens when a user loses access? Decide the answer before you build recovery.
- Which chains do you need? Key formats, account models and fees differ across networks.
- What features depend on the design: fiat purchases, swaps, staking, limits, team approvals?
- Who is responsible for support, fraud handling and incident response?
A consumer app aimed at beginners often leans toward MPC or a custodial design for easier recovery. A tool for experienced users often leans toward non-custodial. A company treasury often uses multi-signature or MPC with approval policies.
Risks that apply to all three
Phishing, malicious dApp requests, compromised devices and mistakes in transaction details affect every wallet type. Good wallet software helps by showing clear transaction previews, warning about unusual approvals and keeping secrets out of logs. It cannot stop a user from approving something harmful, and no design is free of risk. Independent review of key handling and signing code is sensible whichever model you pick, and it reduces risk without removing it.
If you are weighing a wallet build and want to talk through the options, chat with us on WhatsApp at +1 (929) 450-3261 or on Telegram.