Range queries need to include start, end and step parameters in the URL query string.
This example will work, but won't return any data - because you won't have any metrics stored for these dates:
curl 'localhost:9090/api/v1/query_range?query=fulfilment_in_flight_total&start=2021-07-11T00:01:30Z&end=2021-07-11T01:00:00Z&step=15s'
You'll see:
{"status":"success","data":{"resultType":"matrix","result":[]}}
You can use an RFC 3339 date or a Unix timestamp as the start and end values.
In PowerShell you can store the current date and one hour ago in variables like this:
$now=Get-Date
$end=(Get-Date -Date $now -UFormat %s)
$start=(Get-Date -Date $now.AddHours(-1) -UFormat %s)
OR in Linux/macOS:
now=$(date)
end=$(date -d $now +%s)
start="$(date -d "$now - 1 hours" +%s)"
Then query the API using the variables in the URL - this works for PowerShell and Bash:
curl "localhost:9090/api/v1/query_range?query=fulfilment_in_flight_total&start=$start&end=$end&step=30s"