How does the count parameter affect the history result when both start and end timestamps are specified?

The count parameter restricts the number of messages to return (with a max of 100 per request). This remains true regardless of other parameters used in the request - start, end or reverse

If both start and end parameters are provided, the reverse parameter is ignored and the traverse direction is assumed to be from start towards end always. The request will return a max of 100 messages if no count is provided, otherwise the result will be restricted to whatever the count parameter is set to if < 100.

See more about using history in the tutorials and the API reference on our docs site.