Can POST requests in web development be considered safe for repeated execution and having the same effect?

POST web requests are usually not considered safe for repeated execution and are not idempotent, meaning that repeated calls can lead to different results (for example, creating multiple records).

Unlike GET, which should be idempotent and safe, POST is intended for creating or modifying data. Repeating a POST request can cause duplication of operations if the server does not implement protection.

To avoid issues, the following are often used:

• Using unique tokens (such as CSRF tokens or unique transaction identifiers) to prevent reprocessing.
• Redirecting after POST (Post/Redirect/Get) to prevent form resubmission when refreshing the page.

Example in C# ASP.NET:

[HttpPost]
public IActionResult CreateItem(ItemModel model)
{
    if (ModelState.IsValid)
    {
        // Check for uniqueness to avoid duplication
        if (!ItemExists(model.UniqueId))
        {
            SaveItem(model);
            return RedirectToAction("Success");
        }
    }
    return View(model);
}