The Problem with Local Blockchain Development Developing against a live blockchain network is slow by default. Transactions confirm in seconds at best. Reproducing a precise on-chain state for testing requires replaying a sequence of transactions in the right order, signed by the right keys. The alternatives are mocking the chain or stubbing the indexer. Both trade one problem for another. You end up testing against a model of the blockchain rather than the blockchain itself. That gap has a way of hiding bugs until the worst possible moment. For UVerify, we needed something better. The UVerify sandbox built with Yano and Yaci Store is the result. The Stack The UVerify sandbox runs six Docker services. Three of them are the interesting ones. Yano is a local running Java Cardano node . It produces blocks, exposes a Cardano node-to-node (N2N) port for downstream indexers, and provides a Blockfrost-compatible REST API.…