Jupyter kernels Jupyter is a server but also an ecosystem of tools for data exploration. JupyterLab is a web interface to notebooks which can be used to document, visualize and perform computations. Computations in Jupyter are performed by a kernel, a separate component that understands how to perform calculations on request and return the result back to Jupyter. As such, a single JupyterLab installation can have multiple kernels with different configurations for different needs.