This page is just a reference of all the known Steam APIs, I do not know how they work. Please do not email me with questions.
https://api.steampowered.com/ISaleFeatureService/GetAllUserActionDataForType/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
int32 Noenum
uint32 No
uint32 No
https://api.steampowered.com/ISaleFeatureService/GetFriendsSharedYearInReview/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 NoWhose friends we are looking
uint32 NoThe period being queried
bool NoValve/Support can also request private ones too
https://api.steampowered.com/ISaleFeatureService/GetMultipleUserActionData/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
fixed64[] No
int32 Noenum
UNDOCUMENTEDGetUserActionData
https://api.steampowered.com/ISaleFeatureService/GetUserActionData/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
fixed64 NoThat Event GID or Giveaway GID etc...
int32 Noenum
https://api.steampowered.com/ISaleFeatureService/GetUserSharingPermissions/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
uint32 No
https://api.steampowered.com/ISaleFeatureService/GetUserYearAchievements/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
uint32 NoThe period being queried
uint32[] NoThe apps to filter down to
bool NoIf true, we do not generate the game_achievements fields
https://api.steampowered.com/ISaleFeatureService/GetUserYearInReview/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
uint32 No
bool No
int32 NoEYearInReviewAccessSource
bool No
https://api.steampowered.com/ISaleFeatureService/GetUserYearInReviewShareImage/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
uint32 No
string No
https://api.steampowered.com/ISaleFeatureService/GetUserYearScreenshots/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
uint32 NoThe period being queried
uint32[] NoThe apps to filter down to
https://api.steampowered.com/ISaleFeatureService/GetYIRCurrentMonthlySummary/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
https://api.steampowered.com/ISaleFeatureService/SetUserSharingPermissions/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
fixed64 No
uint32 No
int32 Noenum