Mark,  The latter scenario where you create a zero or small initial object and then use the range header to append updates is the correct approach.  Atmos requires that the content-length be set to a non-zero value unless your intention is to truncate the object.   Raj
I'm planning on writing HTTP requests to Atmos to store data using POST /rest/namespace/etc but I don't have all the data upfront. It's being fed in by another application. Does anyone know if I can use chunked transfer encoding (size + data, end with a zero size) to tramsit data because I don't know the Content-Length up front?  My plan B would be to write the first packet of data to a new object, then append each subsequent packet of data using a range header to stipulate "append". But this seems a bit clunky. Chunked encoding would be the way to go if supported.
Does Atmos support chunked transfer encoding?