During March 2025, Vaillant developed a Signer API for the 0xPARC/parcnet repository, focusing on secure and scalable private key handling for POD creation. Using Go, Vaillant designed a Signer struct that encapsulates private key parsing, decoding, and signing, centralizing these operations to reduce redundancy and improve robustness. The implementation included enhanced validation for private key formats, addressing input correctness and security concerns. By streamlining mass POD creation through a dedicated signer client, Vaillant’s work leveraged skills in API design, backend development, and cryptography. The project demonstrated depth in backend engineering, emphasizing maintainability and secure workflow improvements without bug fixes.