A wallet connection that does not leak a seed phrase:
built with the encryption that keeping real money needs
Wallet integration ranges from a simple connect-and-sign flow to building a full multichain wallet from scratch. We have shipped both, including a ten-chain wallet with HD key derivation from one mnemonic, argon2id and AES-256-GCM encryption of seeds, and TOTP two-factor authentication.
What it is
Crypto wallet integration covers two genuinely different builds that both get called “wallet integration.” The lighter one connects your app to a wallet a user already has, MetaMask, Rainbow, Trust Wallet, through a standard protocol like WalletConnect, so your app never touches private keys at all. The heavier one builds an actual wallet, key generation, encrypted storage, multichain support, signing, from scratch, which is a meaningfully larger security and engineering undertaking because your application becomes directly responsible for keeping real money safe.
When you need it (and when you do not)
You need a connect flow when your product is a dapp, marketplace or service that needs users to sign transactions or prove ownership, and users already have or are expected to bring their own wallet; this is the lower-risk, faster path and the right default for most products. You need a full wallet build when owning the key management experience, a card-provider integration, a specific custodial product, a simplified onboarding that cannot assume users already have a wallet, is genuinely core to what you are building.
You do not need either if your product’s crypto functionality is this thin: displaying prices, accepting a payment through a payment processor that handles wallet interaction itself. Those cases need an API integration, not wallet infrastructure.
How we build it
For a connect flow, we integrate WalletConnect or a chain-specific SDK, so a user approves a connection from their existing wallet app and signs transactions there, with your app never handling private keys or seed data at all, which is both simpler to build and meaningfully lower security risk.
For a full wallet build, we derive keys using the BIP39/BIP44 standard from a single mnemonic phrase, extending across whichever chains are in scope, the same approach behind a ten-chain wallet we built spanning Ethereum, BNB Chain, Polygon, Arbitrum, Optimism, Base, Avalanche, Solana, Bitcoin and TON. Seed storage is encrypted with argon2id key derivation and AES-256-GCM encryption, with TOTP two-factor authentication as an additional layer, and the architecture built on a Turborepo monorepo with a Fastify backend, Next.js web client and Expo mobile client, so logic is shared rather than duplicated across platforms. Live price feeds run over WebSocket, and swap functionality integrates aggregators like 1inch for EVM chains and Jupiter for Solana to route trades at competitive pricing.
What to watch
A wallet holding real user funds is a fundamentally higher-stakes build than typical application software; a security mistake here is not a bug to patch, it can be money gone permanently. We treat this with the caution that implies: extensive testing, no shortcuts on encryption, and an honest recommendation against building a custom wallet when a connect flow would serve your actual use case with less risk.
Regulatory treatment of custodial wallet products varies significantly by jurisdiction, and holding user funds, even temporarily, can trigger licensing requirements we are not qualified to advise on; we will tell you plainly when your use case needs legal review before we build it.
Price and timeline
| Option | Price | What it covers | Timeline |
|---|---|---|---|
| Connect flow | from $4,000 | WalletConnect integration, signing flow, balance display | 4 to 6 weeks |
| Full wallet build | from $11,000 | HD key generation, encrypted storage, multichain support, swaps | 7 to 14 weeks |
Running cost depends on usage: a connect flow has minimal ongoing cost beyond standard hosting; a full wallet adds price feed and swap aggregator API costs, usually $20 to $150 a month depending on active user count.
Related
Pairs with smart contract and token launch and NFT minting and marketplace for products built around a specific token or collection. See the development service page for the full build. For our own multichain wallet build, see the ten-chain crypto wallet case study, and for platform and development work on a live crypto trading project, the crypto trading project PM case study.
Deciding between a connect flow and building your own wallet? Get in touch and we will recommend based on what your product actually needs.
FAQ
How much does crypto wallet integration cost?
From $4,000 for a WalletConnect-based connect flow letting users use their existing wallet (MetaMask, Rainbow, Trust) with your app. Building a full wallet from scratch, HD key generation, encrypted storage, multichain support, typically runs $10,000 to $20,000 depending on how many chains are in scope.
Should we build our own wallet or just support connecting existing ones?
Supporting existing wallets via WalletConnect is faster, cheaper and avoids the significant security responsibility of holding user keys. Building your own wallet makes sense when your product needs it as a core feature, a card-provider integration, a custodial product, a specific onboarding flow existing wallets cannot support, not as a default choice.
How do you keep seed phrases secure?
Through encryption at rest, argon2id for key derivation from a user's password, AES-256-GCM for encrypting the actual seed data, and TOTP two-factor authentication on top. Seeds are never stored or transmitted in plaintext, and the architecture is designed so even a database compromise does not directly expose usable seed data.
Which chains can be supported?
We have built support across Ethereum, BNB Chain, Polygon, Arbitrum, Optimism, Base, Avalanche, Solana, Bitcoin and TON from a single HD wallet mnemonic. Additional chains are generally addable using the same BIP39/BIP44 derivation standard where the chain supports it.
Can users swap tokens inside the app?
Yes, through swap aggregation integrations like 1inch for EVM chains or Jupiter for Solana, which route a swap through the best available price across multiple decentralized exchanges rather than a single pool.