Party Animals

There are 3 factors for earning xp in this game.
1. Your First win of the day.
2. Winning a match.
3. The length of the game.

edit: Credit to Jayowski for this information as of as of today (2023/12/19) the most-recent patch removed the custom game daily xp limit.
I have been AFKing custom matches with bots for over three hours now and I am still not capped!
If you do not want to login daily just to hit lv100 now it's your time to grind it out.
Your first win of the day gives 2000 xp, every match you win gives 2000 xp, and the time played goes anywhere from 500 xp-800 xp so if you get a win with first win of day bonus thats around 4500-4800 xp and if you are winning matches youd get around 2500 xp-2800 xp a game and if losing around 500-800 xp. Xp can also be earned in custom games for the same amount as quick match but there is a daily xp cap. You can do a good amount of games and a few levels before you hit the daily cap. You know youve hit the cap when you finish a custom game and it will say daily custom games xp limit has been reached in grey text on your xp bar. The more full the lobby is with human players in customs the more xp you get so if you have a full lobby of 8 human players (not bots) youd get 2000 xp per win and it drops by 250 for every less player in the lobby so if u have 6 players its 1500 xp for a win. If you want to just do your Fwotd and hop off or just farm daily cap in customs i would recommend doing ichiban last stand (2 teams) and set the HP modifier to 1 % so 1 hit Ko’s the other team. The match ends super fast and you can take turns winning on either team until you hit the custom games xp cap.

For people wanting to grind this out solo, here's an easy way to gain XP in custom games (until you reach the daily custom game XP cap at about 4 levels worth of XP)

Go into Custom Games

Create Match

Click the lock so the game is private

Select Maps: Last Stand

Select all maps EXCEPT Blackhole

Settings:

Max HP = 1%

Last Stand Teams = 2 Teams

Teams:

Add 3 AI bots to your team with hard difficulty

Add 1 AI bot to the other team with easy difficulty


Once you start the game just sit still and the AI will win the game for you. each map takes around 1 minute, and it will cycle through all 8 maps before you have to check back in and hit start again.

The first win of the day will grant you 2000 XP. And every single game after that you will gain around 600 XP.

Takes around 30 - 45 minutes to hit this cap. But doing this is MUCH faster than playing quick matches and hoping you win.


If you want to do this even FASTER you could grab friends and do the same method but replace the bots with real people and you can hit the XP cap within 10-15 minutes as XP per win goes up for every real person you have in the game.

But this method can get you around 3-5 levels a day if youre willing to spend 30-45 minutes AFKing. I know 3-5 is not what you wanna hear but the XP per minute is way faster in custom games than quick matches. So you can do this every day, then spend the rest of the day in quick matches until you get 100.