Duolingo Private API

duodroid-api.md

Duolingo Private API

I was bored and I wanted to know how to force a friend quest, so I decided to figure out which endpoint is used to do so. The method I used was using Proxyman to intercept the app's requests and decompiling the apk to read the .smali files.

Endpoint

The endpoint that the APP uses is https://android-api-cf.duolingo.com/, sometimes https://android-api-cf.duolingo.com/2017-06-30/ is used to indicate the API version (I think?).

Auhtorization

In order to use the API, you need to send an Authorization header, which is a Bearer token.

Friends Quests

Quest Object Structure

name	type	description
questId	string	the quest ID, in this format: startTimeSeconds|goalId|friendId
goalId	string	the goal ID of the quest, can be one of the found here
questThreshold	integer	this is the threshold that must be reached to complete the quest
questState	string	this is the current state of the quest, can be one of the found here
?completed	boolean	whether the quest is completed
?acknowledged	boolean	whether the quest is acknowledged that it's completed (?)
goalCategory	string	the goal category, can be one of the cound here
questPoints	integer	the number of points that will be added to the user's monthly goal when the quest is completed
otherQuestParticipants	Quest Participant object	the data of the other quest participants

Match Object Structure

name	type	description
matchSameClient	boolean	unknown
matchSameCourse	boolean	whether the match is the same course
matchedUser	match user object	the matched user's
potentialMutualFriends	number	the number of potential mutual friends that you could have started a match with (?)
user	match user object	your own match user
userTriggeredMatch	boolean	whether the own user started the match

Goal IDs

value	description
xp_friends_quest	friend quest with xp goal
lessons_friends_quest	friend quest with lessons goal

Goal States

value	description
FINISHED	friend quest is finished
NOT_STARTED	friend quest has not started

Goal Categories

value	description
FRIENDS_QUESTS	the goal is a friend quest

Quest Participant

name	type	description
userId	string	the ID of the participant
displayName	string	the displayed name of the participant
avatarUrl	string	the url of the other participant
historicalStats	Historical Quest Stats object	the historical stats of the other participant

Historical Quest Stats

name	type	description
goalCategory	string	the goal category
streak	string	the streak of that goal category

Match User

name	type	description
id	integer	the user's ID
name	string	the user's name
picture	string	the user's picture

GET - /users/{user_id}/quests (note: this endpoint doesn't require API version)

Gets the own user's last and active friends quests.

Parameters

name	description
timezone	the timezone (not sure if this is even used)

Response

name	type	description
quests	list of quests	the list of last and active friends quests

GET - /friends/users/{user_id}/friends-quests/match (note: this endpoint does require the API version)

Gets the current friends quests match.

Response

name	type	description
match	Match object	the current friends request match

POST - /friends/users/{user_id}/friends-quests/match (note: this endpoint does require the API version)

Start a friends quests match with someone.

JSON Parameters

name	type	description
targetUserId	string	the ID of the user you would like to start a match with

Response

name	type	description
success	boolean	whether starting the match succeed