SentSpace is a modular framework for streamlined evaluation of text. SentSpace characterizes textual input using diverse lexical, syntactic, and semantic features derived from corpora and psycholinguistic experiments. Core sentence features fall into three primary feature spaces: 1) Lexical, 2) Contextual, and 3) Embeddings. To aid in the analysis of computed features, SentSpace provides a web interface for interactive visualization and comparison with text from large corpora. The modular design of SentSpace allows researchers to easily integrate their own feature computation into the pipeline while benefiting from a common framework for evaluation and visualization. In this manuscript we will describe the design of SentSpace, its core feature spaces, and demonstrate an example use case by comparing human-written and machine-generated (GPT2-XL) sentences to each other. We find that while GPT2-XL-generated text appears fluent at the surface level, psycholinguistic norms and measures of syntactic processing reveal key differences between text produced by humans and machines. Thus, SentSpace provides a broad set of cognitively motivated linguistic features for evaluation of text within natural language processing, cognitive science, as well as the social sciences.