[en] Future blockchain applications are anticipated to serve millions of users. Thus the evaluation of new blockchain applications have to consider large-scale assessment of the technologies behind the scene. Most of current testing approaches have been done either on simulators or via local small blockchain networks. Hence, the performance in real world conditions is unpredictable. This demonstration introduces BlockZoom, a large-scale blockchain testbed that runs on top of a highly reconfigurable and controllable HPC platform. BlockZoom presents a reproducible environment for experimenting distributed ledgers technologies and smart contract applications. Through different configuration scenarios developers can evaluate the applications performance and the blockchain behavior at a scale comparable to the production environment. The target audience of this demonstration includes researchers and developers in blockchain technology.