title: What are the restrictions on object IDs in Amazon S3?
body: <p>I recently found out that you can fake directory structure on S3 by putting slashes in your filenames. That got me thinking: are there any restrictions at all on object IDs? I'm sure there must be some. Length? Null characters (\0)? Arcane stuff like invalid UTF-8 characters? </p>
  
  <p>I'm sure there must be some restrictions, but I can't seem to find them anywhere in the documentation.</p>