You can make money on Polymarket without having any trades at all. Many markets offer Liquidity Rewards: you place bid/ask brackets close enough to the spread, and every minute Polymarket scores market makers around the spread and distributes rewards proportionally. Some markets distribute hundreds, and even thousands, of dollars per day.
At first glance, this looks simple. It is easy to vibe-code a bot that holds a bid/ask bracket around the mid price in a specific market and reposition orders as the market moves.
In practice, though, liquidity reward farming is tricky.
Calm markets with stable prices and decent rewards attract a lot of liquidity. Your reward share becomes small, so you will make very little unless you commit thousands of USDC.
You can find markets with little or no liquidity around the spread and dominate them. But that comes with significant jump risk. Your orders will eventually get filled, leaving you with a position. Then you need a solid strategy to unwind that position, and you will likely give back a meaningful part of your rewards through liquidation losses.
These jumps can also come from manipulators targeting naive market-making bots that keep quoting no matter what. In low-liquidity markets with wide spreads, a well-funded trader can create fake depth at lower prices, buy against MM bot liquidity, then move the market higher and sell back to those same bots for profit. Without protection from these scenarios, you will bleed money.
So your market-making algorithm needs many moving parts and safety checks if you do not want to get butchered by market jumps and manipulators.
Personally, I found a relatively safe approach: hunt for markets with an established spread where you can be the only active market maker. You can find such opportunities in markets paying around $10-$30 per day. If you are the only contender for the reward, you can hold the widest allowed spread, which gives at least some protection.
Example setup:
This setup earns rewards at about $30/day, and you only need about $100 allocated to maintain the bracket. Do not expect this to last all day, though. Eventually it will attract more market makers, your rate will drop, so you should constantly keep searching for the next opportunity.