Best Wallet

The crypto wallet space in 2024 was fragmented and frustrating. Most wallets supported only a handful of blockchains, forcing users to juggle multiple apps to manage their portfolios. The wallets that did support multiple chains were overwhelmingly technical — seed phrase management, gas fee calculations, and bridge interactions that alienated anyone who wasn't already deep in DeFi.

Leonardo Pavkovic and his team had a clear thesis: the next wave of crypto adoption would come from simplifying the multi-chain experience to the point where managing assets across Bitcoin, Ethereum, Solana, and 50+ other networks felt as intuitive as checking a bank account. No KYC barriers, no custodial risk, no PhD in blockchain required.

The technical challenge was immense. Each blockchain has its own signing algorithms, transaction formats, fee structures, and RPC endpoints. Cross-chain swaps require routing through multiple DEXs and bridges simultaneously to find optimal pricing. Staking involves different validator mechanisms across every proof-of-stake network. And all of this needed to be wrapped in an interface that a first-time crypto user could navigate confidently — while maintaining the security standards that experienced users demand (non-custodial key storage, biometric authentication, hardware wallet compatibility).

The team needed a development partner who understood both crypto infrastructure and consumer app UX — and could ship a production-ready multi-platform app within 20 weeks.

We built Best Wallet as a cross-platform Flutter application with a NestJS backend, designed from the ground up to abstract blockchain complexity behind an intuitive interface.

The wallet architecture uses a modular chain adapter pattern — each supported blockchain (60+) has its own adapter handling key derivation, transaction signing, balance fetching, and fee estimation. This pattern made it possible to add new chains rapidly (average 2 days per chain integration) without touching the core wallet logic. Private keys are generated and encrypted on-device using the Fireblocks SDK, with biometric authentication (Face ID, fingerprint) and optional 2FA for an additional security layer.

The cross-chain swap engine was the most technically demanding component. We built a DEX aggregator that queries 330 decentralised exchanges and 30 bridges simultaneously, comparing routes across multiple hops to find the optimal price with minimal slippage. The UI presents this complexity as a simple "Swap" button with real-time price quotes and estimated fees — one tap to swap ETH on Ethereum for SOL on Solana.

The staking aggregator scans hundreds of validators across every proof-of-stake network, comparing APY rates, commission percentages, uptime history, and lock-up periods. Users see a ranked list of staking opportunities across all their holdings, with one-tap delegation and auto-compounding options.

The portfolio dashboard provides a unified view across all chains — real-time balances, price charts, profit/loss tracking, and transaction history. We integrated Koinly and Blockpit APIs for crypto tax reporting, letting users generate tax documents directly from the app.

The DeFi browser gives users direct access to decentralised applications through an in-app WebView with injected Web3 provider, supporting WalletConnect for seamless dApp interactions without exposing private keys.

Infrastructure was deployed on AWS with auto-scaling groups to handle the volatile traffic patterns typical of crypto markets (price pumps drive 10-20x traffic spikes within minutes). Redis handles real-time price caching, and PostgreSQL stores user preferences and analytics.