Crypto wallet development with institutional-grade security

A custodial wallet means a third party (your platform) holds and manages the private keys on behalf of users. This is similar to how a traditional bank holds funds — users log in with email and password, and the platform handles key management, transaction signing, and recovery. Non-custodial wallets give users full control of their private keys, typically stored on-device or in a hardware wallet. The user is solely responsible for key backup and recovery. Custodial wallets offer better UX and easier onboarding (critical for mainstream adoption), but require more regulatory compliance — in Malta, custodial wallet providers fall under the MFSA VFA framework and need appropriate licensing. Non-custodial wallets have fewer regulatory requirements but shift all security responsibility to the end user. Many modern platforms use a hybrid approach — MPC (multi-party computation) wallets that split key shares between the user, the platform, and a recovery service, combining institutional security with user sovereignty.

MPC (Multi-Party Computation) and multisig are both threshold security mechanisms, but they work very differently. Multisig requires multiple independent on-chain signatures (e.g., 2-of-3) to authorise a transaction — each signer has a complete private key, and the multisig logic is enforced by the smart contract. This means multisig wallets are chain-specific, have higher gas costs (multiple signatures verified on-chain), and the multisig configuration is publicly visible on the blockchain. MPC, by contrast, splits a single private key into multiple shares distributed across different parties (user device, server, recovery service). These shares are never combined — instead, each party computes a partial signature, and the results are combined into a single standard signature. MPC is chain-agnostic (works on any blockchain without special smart contract support), produces standard transactions with no additional gas cost, and keeps the threshold configuration private. For institutional-grade wallet infrastructure, we typically recommend MPC with HSM (Hardware Security Module) backing for server-side key shares.

The cost depends significantly on the wallet type, supported chains, and feature set. A basic single-chain non-custodial mobile wallet with send/receive, transaction history, and token management starts at EUR 30,000 to EUR 50,000. A multi-chain non-custodial wallet supporting Ethereum, Bitcoin, Solana, and major L2s with WalletConnect integration, NFT display, dApp browser, and swap aggregation typically ranges from EUR 60,000 to EUR 100,000. A custodial or MPC wallet platform with institutional-grade key management, KYC/AML integration, multi-approval workflows, and MFSA VFA compliance architecture ranges from EUR 100,000 to EUR 200,000+. Enterprise wallet-as-a-service platforms with white-label capabilities, API access, and multi-tenant architecture can exceed EUR 200,000. We recommend starting with a focused MVP covering your primary use case and target chain, then expanding features based on user feedback.

We build multi-chain wallets supporting all major blockchain ecosystems. For EVM-compatible chains — Ethereum, Polygon, Arbitrum, Optimism, Base, BNB Chain, Avalanche, and any EVM chain — we use a unified architecture since they share the same address format and transaction signing. Bitcoin requires a separate UTXO-based transaction model. Solana uses Ed25519 key pairs and a distinct account model. We also support Cosmos SDK chains (via IBC), Tron, and other ecosystems as needed. For HD (Hierarchical Deterministic) wallet architecture, we implement BIP-32/BIP-39/BIP-44 standards so users can manage multiple chains from a single seed phrase. Multi-chain support extends to token standards — ERC-20, BEP-20, SPL tokens, and native assets across all supported chains. We also integrate cross-chain bridges and swap aggregators so users can move assets between chains directly within the wallet.

Security is the foundational concern in wallet development. Our security architecture includes multiple layers: key generation uses cryptographically secure random number generators with entropy from multiple sources. For non-custodial wallets, private keys are encrypted with AES-256 and stored in the device secure enclave (iOS Keychain / Android Keystore). Biometric authentication (Face ID, fingerprint) gates access to signing operations. For custodial and MPC wallets, we implement HSM (Hardware Security Module) integration for server-side key storage — keys never exist in plaintext outside the HSM. Transaction signing happens within the secure enclave or HSM. We implement transaction simulation to show users exactly what a transaction will do before they sign, protecting against phishing and malicious dApp interactions. Rate limiting, withdrawal limits, address whitelisting, and multi-factor authentication provide additional layers. For enterprise deployments, we add role-based access control, multi-approval workflows, and IP whitelisting.

ERC-4337 is an Ethereum standard that enables smart contract wallets with programmable logic — moving beyond the limitations of traditional externally owned accounts (EOAs). With account abstraction, wallets can support gas sponsorship (users do not need to hold ETH to transact), batched transactions (multiple operations in a single user action), social recovery (recover access via trusted contacts instead of seed phrases), session keys (approve a dApp to sign transactions on your behalf for a limited time), and custom validation logic (e.g., spending limits, time locks). For consumer-facing wallet applications, we strongly recommend implementing ERC-4337. It dramatically improves the user experience — users can onboard with just an email, never need to manage gas tokens, and can recover their wallet without a seed phrase. We build ERC-4337 wallets using battle-tested infrastructure from Biconomy, Alchemy, or Pimlico for bundler and paymaster services, with custom smart account implementations based on the Safe or Kernel architectures.

Yes. We build cross-platform mobile wallet applications using React Native, which allows us to ship native iOS and Android apps from a shared codebase while maintaining access to platform-specific security features — iOS Keychain, Android Keystore, biometric APIs, and push notifications. For the security-critical cryptographic layer (key generation, transaction signing, encryption), we use native modules written in Swift (iOS) and Kotlin (Android) that run within the device secure enclave. The UI layer, networking, and business logic are shared across platforms. This approach gives you 80-90% code reuse while ensuring the most sensitive operations use platform-native security. We also build web-based wallet interfaces and browser extensions for desktop users, using the same backend infrastructure and key management services.

WalletConnect is the industry-standard protocol for connecting mobile wallets to decentralised applications. We implement WalletConnect v2 with full support for multi-chain session management — users can connect to dApps on Ethereum, Polygon, Arbitrum, and other chains simultaneously. The integration includes QR code scanning for desktop-to-mobile connection, deep linking for mobile-to-mobile flows, push notifications for incoming signing requests, and transaction simulation before approval. Beyond WalletConnect, we implement direct dApp browser functionality within the wallet — an embedded WebView that injects a Web3 provider, allowing users to interact with any dApp directly from the wallet without switching apps. We also support EIP-6963 for browser extension wallets, ensuring your wallet is automatically discovered by dApps alongside MetaMask and other installed wallets.