Most of the existing smart contract symbolic execution tools perform analysis on bytecode, which loses high-level semantic information presented in source code. This makes interactive analysis tasks—such as visualization and debugging—extremely challenging, and significantly limits the tool usability. In this paper, we present SolSEE, a source-level symbolic execution engine for Solidity smart contracts. We describe the design of SolSEE, highlight its key features, and demonstrate its usages through a Web-based user interface. SolSEE demonstrates advantages over other existing source-level analysis tools in the advanced Solidity language features it supports and analysis flexibility. A demonstration video is available at: https://sites.google.com/view/solsee/.