Mysainsburys is an employees portal designed for Sainsbury’s to access to the resources such as HR related services, Payroll, Work Schedules and paystubs online at official website mysainsbury.co.uk Sainsbury’s,officially known as J Sainbury plc, is a Second largest supermarket chain in the United Kingdom. Established in 1869 by John James Sainsbury, the company started with a store located in Drury Lane, London.