Imagine: you launch a DeFi protocol and users complain about fund freezing by a centralized provider. Or you lose confidence in the safety of a seed phrase on the server — one leak is enough to compromise all assets. The solution is a non-custodial wallet where private keys are generated and stored locally, and signing happens offline. We build such wallets from scratch — from architecture selection (HD, MPC, ERC-4337) to deployment in mobile and web environments. With 5+ years of experience in custom crypto wallet development, we have launched more than 30 wallets for EVM networks, including 5 with MPC architecture and 3 with full account abstraction support. Clients range from NFT marketplaces to corporate custodians. We work with Solidity 0.8.x, Rust (Anchor for Solana), Foundry, and Tenderly for simulation.
How Wallet Architecture Affects Security
The choice of architecture determines both protection and user experience.
HD Wallet (BIP-32/44) — the basic scheme for most wallets. A tree of keys is derived from a seed phrase of 12 or 24 words. The user backs up only the mnemonic, and the wallet recovers all accounts. Derivation for Ethereum: m/44'/60'/0'/0/n. If the seed is leaked, all keys are lost — single point of failure.
MPC Wallet (Multi-Party Computation) — the key never exists in its entirety. Signing through threshold signature (GG20, CGGMP21). This eliminates the single point of failure but is more complex to implement and requires more computing resources. According to our audit data, MPC wallets are 3 times safer than HD for storing sums over $1M. Our typical MPC wallet project costs start from $50,000, delivering enterprise-grade security.
Smart Contract Wallet (ERC-4337) — the account is replaced by a smart contract with Account Abstraction. This provides social recovery, batched transactions, gasless operations via Paymaster, and multi-signature without a separate contract. Gas savings for the user can reach 30% when using Paymaster.
| Parameter | HD | MPC | SC Wallet |
|---|---|---|---|
| Security | High (seed) | Very High | High (contract) |
| UX | Simple | Medium | Flexible |
| Transaction Cost | Low | Medium | High (gas) |
| Recovery | Seed phrase | Key shares | Social |
How to Ensure Secure Private Key Storage
Each platform requires its own approach:
| Platform | Solution | Security Level |
|---|---|---|
| iOS | Secure Enclave + Keychain | High |
| Android | StrongBox / TEE + Keystore | High |
| Desktop | OS keychain + AES-256 | Medium |
| Browser Extension | SubtleCrypto + encrypted storage | Medium |
| Hardware | Secure Element (HSM) | Maximum |
The seed phrase is encrypted with Argon2id using the user's password before being written to storage. No MD5 or SHA1. In our projects we also use entropy with the ethers.utils.randomBytes library. We guarantee that no key material ever leaves the user's device.
Why Order Non-Custodial Wallet Development from Us?
We don't copy open-source — we adapt the architecture to your use case. MPC wallets are safer than HD for storing large amounts because the key is never assembled in one place. Our experience includes integration with ERC-4337 and BIP-32. With over 30 successful wallet projects and a 5-year track record in blockchain, we bring certified expertise.
A recent case: for an NFT marketplace we implemented HD + Account Abstraction with social recovery and gasless transactions. User retention increased by 40%, and the average fee dropped by 25% (saving users approximately $0.50 per transaction). We completed it in 10 weeks at a cost of $80,000.
EIP-4337 introduces account abstraction without changing the consensus layer. — from Ethereum.org.
What Are the Development Timelines and Costs?
MVP for a single EVM network — from 4 weeks at $30,000. A full product with MPC, NFT support, WalletConnect, and multichain — from 12 weeks at $80,000. The cost is calculated individually after requirements analysis. We provide a guaranteed fixed price after scoping.
Contact us to discuss your project. We will assess the task in 2 business days.
Our Development Process
- Requirements analysis: determine target platform, required networks, token standards.
- Design: choose architecture (HD/MPC/SC), design UI/UX and secure storage.
- Implementation: write smart contracts (Solidity 0.8.x) and client side (React Native / Flutter / Extension).
- Testing: unit tests, fuzzing (Echidna), transaction simulation (Tenderly).
- Deployment and audit: deploy contracts, conduct external audit (Certik, Hacken).
For security testing we use static analysis with Slither, fuzzing with Echidna, simulation in Tenderly, and external audit by leading firms. This covers 95% of vulnerabilities. We offer a 6-month security guarantee covering all code we deliver.
What Is Included
- Architecture and API documentation
- Wallet source code from scratch with full ownership
- WalletConnect v2 and Web3 provider integration
- EVM wallet support (Ethereum, BSC, Polygon, Arbitrum, Optimism)
- Automatic ERC-20 and NFT detection
- Transaction simulation before signing
- Client team training (2 sessions)
- Technical support for 1 month after launch
- Deployment scripts and CI/CD pipeline setup
- Access to private git repository and project management board
Typical Mistakes in Self-Development
- Using insecure seed storage (e.g., in SharedPreferences).
- Lack of transaction simulation — the user does not see what they are signing.
- Ignoring EIP-1559: the wallet does not pick the optimal gas price.
- Forgetting multichain compatibility: the user might lose funds when transferring to another network.
Order professional development — and avoid these issues. Get a consultation right now. Our crypto wallet development services are trusted by startups and Fortune 500 clients alike.