File.io vs FileUp

File.io is an anonymous, one-time file-transfer service: uploaded files get a short-lived link that self-destructs after a configurable number of downloads, with a simple REST API returning JSON for uploads and deletions. A live OPTIONS preflight with an Origin header against the real host, www.file.io, returned a 403 with no Access-Control-Allow-Origin header, resolving cors from unknown to no; no API key is required for basic use, and HTTPS was reconfirmed. A free anonymous tier covers casual transfers, while a paid plan raises file-size limits and adds account-based management.

FileUp is a self-hosted, open-source temporary file-upload and sharing service built on .NET, offering a public REST API for anonymous uploads with configurable expiry times and view limits. A live OPTIONS preflight with an Origin header against the maintainer's own running instance, upload.sinasnp.com/api/public/upload, returned a 204 with no Access-Control-Allow-Origin header, resolving cors from unknown to no; the public upload endpoint requires no auth (only the separate admin panel uses Basic Auth), and HTTPS was reconfirmed. It's a free, open-source project with no paid tier.