Local Notebook File I/O and Cloud APIFunction Sandbox: Resolving Path and Environment Differences Across Deployment Boundaries
A Wolfram Language notebook that reads and writes data using relative file paths such as "data/input.csv" executes correctly on a developer machine because the kernel resolves those paths against the notebook's directory. When deployed as an APIFunction in the Wolfram Cloud, the sandbox may redirect relative paths to a temporary working directory where write