Confirm the write at its destination
Record the bucket and key used for the upload, then inspect the operation result for an error. A successful request confirms acceptance by the storage interface, while a follow-up read or metadata check confirms the object is available where your application expects it.
For large or important files, verify size, content type, and a checksum when available. These checks help distinguish a complete upload from an object with incorrect metadata or truncated content.
Handle retries without overwriting good data
A timeout can occur after the service stores the object but before the caller receives confirmation. Before retrying, read the key or compare its metadata with the intended file; avoid replacing a valid object unnecessarily.
If the destination key is versioned or shared, use a unique temporary key for staging and update the application reference only after verification. Keep a recovery copy for critical data and make cleanup of temporary objects an explicit step.