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.
UNDOCUMENTEDGetPreferences
https://api.steampowered.com/ISteamNotificationService/GetPreferences/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
UNDOCUMENTEDGetSteamNotifications
https://api.steampowered.com/ISteamNotificationService/GetSteamNotifications/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
bool NoWhether to include notifications the user has hidden previously
int32 NoWhat language to get notifications in, for the general type that is pre-localized on the server, default english
bool NoWhether to include counts of pending confirmations
bool NoWhether to include counts of unclaimed gifts or pending friend requests
bool NoWhether to include read notifications
bool NoWhether to return only the count of unread notifications
UNDOCUMENTEDPOSTHideNotification
https://api.steampowered.com/ISteamNotificationService/HideNotification/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
uint64[] No
UNDOCUMENTEDPOSTMarkNotificationsRead
https://api.steampowered.com/ISteamNotificationService/MarkNotificationsRead/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
uint32 NoIf set, marks ALL notifications older than this timestamp read
int32 NoIf set, marks only notifications of a specific type read
uint64[] NoIf set, only the specified notification will be marked read
bool NoMark all of the user's notifications as read
UNDOCUMENTEDPOSTMarkNotificationsViewed
https://api.steampowered.com/ISteamNotificationService/MarkNotificationsViewed/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
uint64 No
uint32 No
UNDOCUMENTEDPOSTSetPreferences
https://api.steampowered.com/ISteamNotificationService/SetPreferences/v1/
NameValueTypeRequiredDescription
click to setstring Yes Access key
SteamNotificationPreference[] No
↳ ESteamNotificationType Noenum
↳ uint32 No