blockchain-integration-builder

Choose a blockchain by matching requirements to chain properties: Ethereum L1 for maximum security, Arbitrum or Base for low-cost EVM, Solana or Sui for sub-second finality, and Cosmos for sovereign appchains. The decision matrix maps throughput, cost, privacy, and interoperability needs to specific chains.

Prevent reentrancy by following the checks-effects-interactions pattern: validate inputs, update state, then make external calls last. Add a nonReentrant mutex modifier that blocks recursive calls, and prefer pull-based payments where users withdraw funds instead of contracts pushing transfers.

Transparent proxies route admin calls to proxy logic and user calls to the implementation, keeping upgrade logic in the proxy. UUPS places the upgrade function inside the implementation contract itself, reducing proxy size and gas costs but requiring each implementation to include upgrade authorization.

Migrating from EVM to Solana requires a full rewrite because Solana uses Rust, stateless programs with separate data accounts, and explicit signer passing instead of msg.sender. Budget two to four times the original development effort and commission a fresh security audit.

Keep computation, storage, and user experience off-chain where it is fast and cheap, and put verification, settlement, and ownership on-chain where trustlessness matters. Bridge the two with oracles, merkle proofs, or signatures, and use indexers like The Graph to query emitted events.