Decide custodial or non-custodial first
A custodial wallet holds keys on behalf of users and carries operational and regulatory responsibility. A non-custodial wallet leaves keys with the user and shifts the burden to recovery and UX. Your partner should explain the trade-offs for your product rather than push one model.
Hybrid options such as MPC split a key into shares so no single device or server can move funds, which suits businesses that want security without a single point of failure.
Chains, tokens and standards
List the networks you need, such as Ethereum-compatible chains, Tron, Bitcoin or Solana, and ask which the team has shipped on. Multi-chain support means different address formats, fee models and confirmation rules, not just a longer dropdown.
Security review and recovery
Ask how keys are generated, backed up and recovered, how transactions are signed and whether an independent audit is included. For business wallets, check approval policies, spending limits, allow-listed addresses and audit trails.
A scorecard for wallet developers
Score vendors on key management design, supported chains, recovery options, transaction signing flow, security review practice, user experience and support for business controls such as approvals and spending limits. Key management and recovery should be weighted highest because they decide whether users or the business can lose funds.
Crypto wallet developer comparison at a glance
| What to check | A strong answer | A warning sign |
|---|---|---|
| Key management | Clear key generation, storage and backup design | Cannot say where keys live |
| Recovery | Defined path when a user loses a device | Recovery is “to be decided” |
| Business controls | Approvals, spending limits, allow-listed addresses | Any one admin can move funds |
| Chains | Shipped wallets on the networks you need | Lists every chain, has built few |
| Review | Independent security review included in the plan | Open-source code copied without review |
Questions to ask in the first call
Ask where keys are generated, where they are stored, what happens if a user loses a device, and how a company wallet requires more than one approver. Ask how fees are estimated and how stuck transactions are handled on each chain.
- Ask where keys are generated and where they are stored.
- Ask what happens when a user loses a device.
- Ask how a company wallet needs more than one approver.
- Ask how fees are estimated and stuck transactions are handled on each chain.
- Ask to see a wallet in production, not a prototype.
Phases of a wallet build
Typical phases are choosing the custody model and chains, designing key management and recovery, building the signing and transaction services, creating the apps and admin tools, testing on testnets and then mainnet with small amounts, an independent security review, and staged release.
Mistakes buyers make
Mistakes include copying open-source wallet code without reviewing it, choosing a custody model to match a competitor instead of your own risk profile, and treating recovery as an afterthought. Users forgive a plain interface far more readily than lost funds.
How NNT Software approaches wallet development
We build custodial, non-custodial and MPC wallets, multi-chain support, approval policies and the monitoring that keeps business funds safe. We respond to every enquiry within 10 minutes, set up a meeting to understand your requirements, share a demo within 24 hours of that meeting, and then send a proposal that matches your budget.
Wallet builds are tested on testnets, then on mainnet with small amounts, before wider release. A free 90-day defect warranty follows go-live and the keys, code and accounts remain yours.
Example scenario: a wallet for business treasury
Illustrative scenario, not a client case: a company wants to hold and move stablecoins for suppliers without any one person being able to send funds alone. The first decision is custody: a multi-party approach with approval policies, rather than a single key on one device.
The build defines who can propose, approve and release a payment, adds spending limits and an allow-list of destination addresses, and logs every action. It is tested on a test network, then on the main network with small amounts, and a recovery drill confirms that funds can be restored if a signer loses access.
Red flags to walk away from
Do not accept a wallet built by copying open-source code that nobody on the team has reviewed, or one where recovery is left until later. Users forgive a plain interface far more readily than lost funds.
Be wary of a custody model chosen only because a competitor uses it. The right design depends on who carries the risk, you or your users.
Experience and cost
Look for a working wallet in production, not just screenshots, and for an honest account of what went wrong in earlier builds. NNT Software’s rates are US$15–40 per hour; the final cost and timeline depend on the chains, features and team assigned, and are agreed after your requirements are final.
Sources and further reading
More buyer guides
How NNT Software delivers projects like this
- Discovery — workshops, requirements and a written scope with a fixed estimate within days.
- Design — user flows, a clickable prototype and an architecture review before coding starts.
- Build — two-week sprints with demos, a shared backlog and code in your own repository.
- Test — dedicated QA, automated regression tests, performance and security checks.
- Launch — zero-downtime deployment, monitoring and user training.
- Support — SLA-backed maintenance and continuous improvement after go-live.