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I will build non custodial crypto wallets and web3 dapps
Senior Blockchain Engineer and Web3 , DeFi Specialist
I build production-grade smart contracts, DeFi platforms, and Web3 systems that ship to real users.
I'm Anisul, a Senior Blockchain Engineer with deep expertise in Solidity smart contract development...
About this Gig
I build non-custodial Web3 wallets, dApps, and token-gated access systems blockchain backend infrastructure built to hold up in production.
I've shipped real systems handling stablecoin settlement across Celo and Polygon, multi-chain wallet analytics across Ethereum, Polygon, and BNB Chain, and wallet-based authentication using Sign-In with Ethereum (SIWE).
What I can build for you:
- Non-custodial wallet integration (MetaMask, WalletConnect, Coinbase)
- Multi-chain support (Ethereum, Polygon, BNB, Base, Celo)
- Token-gated access (ERC-20 / ERC-721 verification)
- RPC integration with automatic failover (Alchemy, Infura)
- Smart contract integration & dApp backend (Node.js/NestJS)
- Real-time blockchain event monitoring (webhooks + queues)
Why work with me:
Most wallet tutorials stop at "connect MetaMask." I build the reliability layer underneath failover, queueing, error handling so your app doesn't break when one RPC provider hiccups.
Message me with your project details before ordering so I can confirm scope and recommend the right package.
Keep your assets and information safe
Cryptocurrency services focus solely on developing and programming. Never share sensitive information or private keys with others.
My Portfolio
FAQ
Do you need my private keys or seed phrase?
Everything I build is non-custodial — you and your users always keep control of private keys. I only need a public wallet address or testnet credentials to build and test against.
Which blockchains do you work with?
Ethereum, Polygon, BNB Chain, Base, and Celo are all within scope. Need a different EVM-compatible chain? Message me first to confirm I can support it.
I'm not sure which package I need
Send me a quick project brief before ordering — what you're building and which chains or wallets matter — and I'll recommend the right package or a custom quote.
Can you build the smart contract too, not just the backend?
Yes, for standard ERC-20/ERC-721 patterns. Highly custom contract logic may need a separate quote — message me with details first.
Do you sign NDAs?
Yes — happy to sign an NDA before you share sensitive project details.
