Adventures in algorithmic trading on the Runescape Grand Exchange

Haha, in the heyday of Runescape it used to be possible to simply have buy and sell orders sitting in the GE for the same rare items simultaneously, and over time they’d both get filled for a profit. I guess you would call it “market making”.

This reminds me of when World of Warcraft had a mobile app that allowed you to both browse the auction house and list or buy items. The API was pretty trivial to reverse engineer, making it easy to write an auction house bot. I never got as sophisticated as any ML algorithm, just snagged grossly mispriced items and bought/sold based on the last week's price range; it was mostly about volume. Made a tidy profit, bought my 1mil gold mount then gave up. The app was taken down soon after, no doubt in part because I'm sure I was not the only person doing this.