Systems, methods, and apparatuses relating to multicast in a configurable spatial accelerator are described. In one embodiment, an accelerator includes a first output buffer of a first processing element coupled to a first input buffer of a second processing element and a second input buffer of a third processing element; and the first processing element determines that it was able to complete a transmission in a previous cycle when the first processing element observed for both the second processing element and the third processing element that either a speculation value was set to a value to indicate a dataflow token was stored in its input buffer (e.g., as indicated by a reception value (e.g., bit)) or a backpressure value was set to a value to indicate that storage is to be available in its input buffer before dequeuing the dataflow token from the first output buffer.