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, encrypted at rest, with swap pricing a user can actually verify.
What it is and who needs it
A crypto wallet app lets a user hold, send, receive and swap assets across one or more blockchains without handing custody to a third party. The hard part is not the send button, it is the key management: how a seed is generated, encrypted and recovered, how a swap quote is checked against a real market rate instead of trusted blindly, and how the app behaves when an RPC node is slow or a chain is congested. Anyone adding multichain support, their own token, a swap feature or a card-ready balance to an existing fintech product needs this, as does a team launching a standalone wallet as the product itself.
What is inside
HD key generation (BIP39 seed phrase, BIP44 derivation paths) so one mnemonic covers every chain you support, with seeds encrypted at rest using AES-256-GCM and argon2id for password hashing, never plaintext, never in logs. A swap screen that 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 over WebSocket instead of a refresh button. TOTP two-factor authentication on top of the password. A backend structured so that 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, because the derivation path 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, this is the part a shortcut here costs you a user’s funds, not 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) so a fix in the wallet logic does not mean fixing it 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, and the first production deployment happens only after the key-management and encryption layer has been reviewed independently. We also test the app’s behavior when an RPC node is slow or temporarily down, a condition that is common on less mature chains and that a wallet needs to handle gracefully rather than showing a confusing error or, worse, a stale balance presented as current. A dedicated review pass covers the recovery flow too, since a seed phrase a user cannot correctly restore from is as damaging as one that was never encrypted properly in the first place.
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, agency keeps running it with you |
| Full control (handover-ready) | from $15,000 | 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, 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 $15,000 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 (viem for EVM, @solana/web3.js, bitcoinjs-lib, @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: seeds are encrypted and stored on infrastructure in your name, 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.