HexPrism is a hex editor designed for CTF competitions and digital forensics work. The tool runs entirely in the browser, providing a client-side environment for file analysis without requiring data to be uploaded to external servers. The editor provides byte-level editing capabilities, allowing users to modify individual bytes within files. It includes file analysis features to examine file structures and contents at the hexadecimal level. The tool incorporates automatic header repair functionality to fix corrupted or modified file headers. HexPrism operates as a lightweight application that processes files locally in the browser. This architecture ensures that files remain on the user's system during analysis and editing operations. The tool is available as an open-source project on GitHub under the BnHany organization. The editor is positioned for use cases including CTF challenge solving, forensic file analysis, and general hex editing tasks where privacy and local processing are priorities.