A multichain crypto wallet,
your keys, your custody, your brand
A wallet app is a trust product before it is a feature list. One leaked seed or one bad swap quote and a user is gone for good. We build non-custodial wallets the way we built our own. Ten chains from one mnemonic. Keys generated and encrypted on the user's device. Swap pricing a user can actually verify.
Why a wallet lives or dies on the keys
A crypto wallet app lets a user hold, send, receive and swap assets across one or more blockchains, without handing custody to anyone else. The hard part is never the send button. It is the key management: how a seed gets generated, encrypted and recovered. It is also how a swap quote gets checked against a real market rate, instead of trusted blindly. And it is how the app behaves when an RPC node is slow or a chain is congested.
This fits anyone adding multichain support, their own token, a swap feature or a card-ready balance to an existing fintech product. It also fits a team launching a standalone wallet as the product itself.
What is inside
HD key generation, a BIP39 seed phrase with BIP44 derivation paths, means one mnemonic covers every chain you support. Keys are generated and encrypted on the user’s device using AES-256-GCM, with argon2id for password hashing. Never plaintext, never in logs, never on our servers.
A swap screen pulls quotes from more than one aggregator and shows the user the comparison, not just the number we think is best. Live balances and prices update over WebSocket instead of a refresh button. TOTP two-factor authentication sits on top of the password. The backend is structured so adding a card provider later, Visa, Mastercard or a regional processor, is a configuration step, not a rebuild.
How we build it
We start with the chain list: which networks matter to your users now, which you will add later. Derivation paths and signing logic differ enough between an EVM chain, Solana, Bitcoin and TON that bolting one on later is real work, not a toggle.
We build the key management and encryption layer first, and get it reviewed before any screen exists. A shortcut here costs a user their funds, not just a bug report. Swap aggregation and pricing come next, wired to more than one source so a quote can be sanity-checked. The mobile app and web client share this core logic through a monorepo structure. We used Turborepo on our own build. A fix in the wallet logic never needs doing twice.
We built exactly this for our own product: ten networks from one seed, two swap aggregators, a card-ready structure waiting on provider credentials. Every build goes through a weekly demo cadence, so you see the wallet working on testnet before it ever touches mainnet funds. The first production deployment happens only after the key-management and encryption layer gets reviewed independently.
We also test how the app behaves when an RPC node is slow or temporarily down, a common condition on less mature chains. A wallet needs to handle that gracefully, not with a confusing error, and never with a stale balance shown as current. A dedicated review pass covers the recovery flow too. A seed phrase a user cannot correctly restore from does just as much damage as one that was never encrypted properly.
Timeline and price
| Tier | Price | What it covers |
|---|---|---|
| MVP | from $4,000 | Core flow, one platform or chain, ready to test with real users |
| Production | from $9,000 | Full feature set, handover docs, we keep working with you if you want that |
| Full control (handover-ready) | from $10,000 | Same scope, built and documented for your own team to run with zero dependency on us |
Timeline: 4 to 8 weeks for an MVP. Production builds typically run longer depending on integrations.
What you own at the end
The full repository, backend and mobile app sit in your GitHub or GitLab from the first commit. Infrastructure runs on a server or cloud account in your name, with deployment, backups and monitoring documented in a handover file. You hold the signing keys to your own release builds on the App Store and Google Play. Nothing about running this product depends on us after handover. Our fee for ongoing changes is the same one any other developer would charge for a codebase they know well.
Related
Part of our custom development work. See related builds: crypto exchange swap interface, defi dashboard, token smart contract launch. On the technical side: crypto wallet integration, two factor authentication. Related case study. Ready to scope yours? Get in touch and we will send back a written plan with a fixed price.
FAQ
How much does a crypto wallet app cost?
A single-chain wallet with send, receive and a swap screen starts at $4,000. A multichain wallet across five or more networks with card-ready infrastructure runs $9,000 to $10,000, depending on how many chains and integrations are in scope. We give you a fixed number after the first call.
How long does it take to build?
4 to 8 weeks for an MVP on one or two chains with core send, receive and swap flows. A production build across multiple chains with a mobile app on both platforms typically takes 8 to 14 weeks.
What is the stack?
Backend in Node.js or Python/FastAPI with PostgreSQL and Redis. Mobile apps on React Native and Expo. Chain libraries such as viem for EVM, @solana/web3.js, bitcoinjs-lib and @ton/ton. Swap aggregators like 1inch and Jupiter, and CoinGecko or a similar feed for pricing.
Who owns the wallet and the keys?
You do, by design. This is a non-custodial product. Keys are generated and encrypted on the user's device, never on our infrastructure. We never hold user funds, and the full repository is yours from the first commit.
What support do we get after launch?
A handover document covering key management, chain RPC dependencies and the swap integration, plus 30 days of fixes after launch. Ongoing security review and new-chain support are available as a monthly arrangement.