Smart Contract Backend Build

I need a complete blockchain-powered backend whose main role is to run and interact with smart contracts. Your task is to design, code, test, and deploy those contracts and then expose their functions through a clean API that my front-end team can consume. The choice of chain and contract language is open; whether you prefer Ethereum, Hyperledger, or Binance Smart Chain, and whether you work best in Solidity, Rust, or Vyper, I am happy to follow your technical lead as long as the solution is secure and maintainable.

Security, gas or resource efficiency, and clear documentation matter most to me. The API should support standard CRUD-style interactions with contract state and include basic authentication so we can drop it straight into our staging environment.

Deliverables
• Fully tested smart-contract source code
• Deployment scripts and configuration files for the agreed network
• Server-side REST or GraphQL API wired to the contracts
• Concise hand-off guide with build, test, and deployment steps

The project is complete when your tests pass on a local fork and I can verify the contract address and ABI on the chosen testnet or mainnet.