There will be an enormous need for sustainable textile processing solutions globally in the future due to evolving legislation and consumer demand. R&D in the field has been active during the recent years and many great process innovations are already operating in lab or pilot scale, some even at demonstration or commercial scale. Upscaling of the technologies is a real test for the feasibility of each technology and reveals if it will be a winner in a race towards circular textile production. Valmet has a broad expertise in fiber processing, innovation, R&D, piloting and scaling-up of processes in the pulp, paper and energy industries and wants to use its knowhow in the sustainable development of the textile fiber industry. Together with innovative companies we can pilot and upscale processes for textile recycling and manufacturing of man-made cellulosic fibers. The paper will discuss the challenges, existing and future solutions as well as opportunities in piloting and upscaling of sustainable textile fiber processes, from the perspective of technology developer and equipment manufacturer, based on the lessons learned and best practices identified.