Working guides to handling file uploads in PHP — the configuration that trips people up, the security decisions that matter, and the techniques behind a modern upload experience. Every example is plain PHP you can use without our component.
How to Upload Multiple Files in PHP
Handling the $_FILES array when a form posts several files at once, and the pitfalls of its unusual shape.
PHP Upload Size Limits Explained
upload_max_filesize, post_max_size, memory_limit and the web-server caps that silently override them.
PHP Upload Error Codes (UPLOAD_ERR_*)
Every value $_FILES['file']['error'] can hold, what actually causes it, and how to fix it.
Secure File Uploads in PHP: A Checklist
Extension allow-lists, MIME verification, storage outside the web root, and the mistakes that lead to remote code execution.
Uploading Large Files in PHP Without Timeouts
Why big uploads fail, how chunked transfer solves it, and what to do about memory and execution limits.
Building an AJAX Upload with a Progress Bar
XMLHttpRequest upload events, FormData, and why fetch() still cannot report upload progress.
Drag-and-Drop File Uploads in PHP
The DataTransfer API, a drop zone that works with the keyboard too, and wiring it to a PHP endpoint.
Where to start
If you are building an upload form from scratch, read multiple file uploads first for the shape of $_FILES, then the security checklist before you accept anything from real users. If something is already broken, the error-code reference and the size-limit guide between them explain almost every upload failure in PHP.
For the experience side — progress bars, cancellation, drag-and-drop and files too large for a single request — see AJAX uploads with a progress bar, drag-and-drop uploads and large file uploads.