Mass File Submission Software

I need a purpose-built tool that lets my travel company push both text files and PDF files to roughly 100–200 social-media-style sites in one go. The workflow should be simple: I pick or drag-and-drop the files, paste in the list of destination URLs (or load them from a CSV), hit “Submit,” and the software handles the rest. Because our focus is only on rapid indexing with Bing, I do not need any post-submission tracking or reporting—just reliable, simultaneous uploading.

Key functions I expect
• Accepts text and PDF inputs in bulk
• Handles 100–200 destinations per batch without throttling issues
• Lets me store site credentials or API keys securely for future runs
• Runs on Windows; a lightweight desktop app or a well-documented script (Python, Node, or similar) is fine as long as setup is straightforward

If you have experience building multi-poster tools, especially for social platforms, your input on efficient request handling and anti-blocking tactics is welcome. Please outline your proposed approach, estimated timeline, and any third-party libraries you intend to use.