Abstract: A system and methodology for data processing combining stream processing and spreadsheet computation comprises: one or more Cloudscale Stream Processors (CSPs), a Cloudscale-enabled spreadsheet (including a plug-in module), a web services architecture, and one or more data sources. Each CSP takes a set of streams of input data and outputs a set of streams of data. Each stream is a time-ordered stream of files which when concatenated together comprise the stream. The Cloudscale-enabled spreadsheet is includes a plug in module that operates in conjunction with a spreadsheet program and one or more stream processors. The Cloudscale-enabled spreadsheet provides tools and technologies for user authentication, stream discovery, data source extraction and new stream design. It includes features for design of new stream processors, as well as features for checking and validation, cycle and synchronization controls for stream processors and spreadsheets.