  We introduce jiant, an open source toolkit for conducting multitask and
transfer learning experiments on English NLU tasks. jiant enables modular and
configuration-driven experimentation with state-of-the-art models and
implements a broad set of tasks for probing, transfer learning, and multitask
training experiments. jiant implements over 50 NLU tasks, including all GLUE
and SuperGLUE benchmark tasks. We demonstrate that jiant reproduces published
performance on a variety of tasks and models, including BERT and RoBERTa. jiant
is available at https://jiant.info.
