Power to heat (P2H) is expected to be the first type of electrification that will drastically transform the chemical industry. This holds in particular for producing its major building blocks: the 300 Mt/yr light olefins via steam cracking at more than 800°C. e-CRACKER will implement P2H by so-called shockwave heating, enabling an increase in temperature to >1000°C in 10 ms, an order of magnitude faster than the current furnace-based technology in a revolutionary High-Mach reactor. When combined with insight in the pressuredependence of the cracking chemistry this will allow to avoid undesired side reactions and to increase olefin yields of ethane and plastic waste derived naphtha cracking by 10 wt.% compared to yield gains of 0.1 wt.%, at best, when applying alternative P2H such as resistive heating. e-CRACKER will: 1. generate new fundamental understanding of shock wave heating and kinetics under sub- and supersonic conditions; 2. demonstrate the practical applicability of an open-source, high fidelity Multiscale Modeling platform in combination with finite rate chemistry for turbulent reacting and rotating flows; 3. develop a compact, energy-efficient, electrified High-Mach reactor generating shockwaves and minimizing side products by avoiding back-mixing; 4. pave the way to avoid more than 200 Mt CO2/yr emissions with a scalable, flexible, step-by-step implementable technology driven by renewable electricity. Starting from fundamental local and global (non-)reactive data collection (WP1), and a high-fidelity open source Multiscale Modeling framework (WP2) novel 3D reactors will be designed in silico using advanced optimization (WP3). The power of the approach will be demonstrated in a 3D-printed High-Mach reactor, which, by operating under unconventional cracking conditions (lower pressures and faster heating) achieves yield increases of more than 10 wt% (WP4), contributing in a decisive way to the transition of the chemical industry.