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.
GETGetSteamIDForBadgeID
https://api.steampowered.com/IDOTA2Ticket_570/GetSteamIDForBadgeID/v1/
NameValueTypeRequiredDescription
string Yes The badge ID
POSTSetSteamAccountPurchased
https://api.steampowered.com/IDOTA2Ticket_570/SetSteamAccountPurchased/v1/
NameValueTypeRequiredDescription
uint64 Yes The 64-bit Steam ID
uint32 Yes Badge Type
GETSteamAccountValidForBadgeType
https://api.steampowered.com/IDOTA2Ticket_570/SteamAccountValidForBadgeType/v1/
NameValueTypeRequiredDescription
uint64 Yes The 64-bit Steam ID
uint32 Yes Valid Badge Type 1
uint32 Yes Valid Badge Type 2
uint32 Yes Valid Badge Type 3
uint32 NoValid Badge Type 4