id

Integer /[0-9]+/

The (unique) id of a resource.

matchday

Integer /[1-4]*[0-9]*/

For the leageTable subresource, the matchday defaults to the current matchday. For former seasons the last matchday is taken. For the fixture resource, it’s unset.

season

String /\d\d\d\d/

Defaults to the current year, given as 4 digit like '2021'

head2head

Integer /[0-9]+/

Define the the number of former games to be analyzed in the head2head node. Defaults to 10.

venue

home|away

Define the venue of the fixtures to be returned.

league

(comma separated) String /[\w\d]{2,4}(,[\w\d]{2,4})*/

A (list of, comma separated) league-code(s). Default is unset and means all available. See the soccerseason list resource for currently available leagues or the appendix of the full documentation for a table of all league codes

while reading and editing documentation I came across the timeFrame argument. That was

timeFrame

p|n[1-9]{1,2}

The value of the timeFrame argument must start with either p(ast) or n(ext), representing a timeframe either in the past or future. It is followed by a number in the range 1..99. It defaults to n7 in the fixture resource and is unset for fixture as a subresource. For instance: p6 would return all fixtures in the last 6 days, whereas n23 would result in returning all fixtures in the next 23 days.

timeFrameStart

\d\d\d\d-\d\d\-\d\d

The start date of the resources to be returned, e.g. 2016-08-01

timeFrameEnd

\d\d\d\d-\d\d\-\d\d

The end date of the resources to be returned, e.g. 2016-08-08