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.
GETGetPlayerItems
https://api.steampowered.com/IEconItems_440/GetPlayerItems/v1/
NameValueTypeRequiredDescription
uint64 Yes The Steam ID to fetch items for
GETGetSchema
https://api.steampowered.com/IEconItems_440/GetSchema/v1/
NameValueTypeRequiredDescription
string NoThe language to return the names in. Defaults to returning string keys.
GETGetSchemaItems
https://api.steampowered.com/IEconItems_440/GetSchemaItems/v1/
NameValueTypeRequiredDescription
string NoThe language to return the names in. Defaults to returning string keys.
int32 NoThe first item id to return. Defaults to 0. Response will indicate next value to query if applicable.
GETGetSchemaOverview
https://api.steampowered.com/IEconItems_440/GetSchemaOverview/v1/
NameValueTypeRequiredDescription
string NoThe language to return the names in. Defaults to returning string keys.
GETGetSchemaURL
https://api.steampowered.com/IEconItems_440/GetSchemaURL/v1/
GETGetStoreMetaData
https://api.steampowered.com/IEconItems_440/GetStoreMetaData/v1/
NameValueTypeRequiredDescription
string NoThe language to results in.
GETGetStoreStatus
https://api.steampowered.com/IEconItems_440/GetStoreStatus/v1/