During December 2025, Dev focused on backend reliability for the coinbase/x402 repository, specifically improving error handling in the SVM signer’s Solana RPC integration. Addressing a bug where BigInt values in error responses caused TypeErrors, Dev implemented a JSON serialization approach that converts BigInt values to strings, ensuring compatibility and reducing runtime errors. This solution was reinforced with targeted unit tests to validate correct serialization in simulation error scenarios, and repository hygiene was improved by updating configuration files. Working primarily with TypeScript, Dev emphasized maintainability and robust testing, prioritizing long-term stability over new features during this period of focused backend work.