Polymarket Reviewing Its Developer Program, Several Mirror Apps Openly Teach Users to "Trade with Insider Traders"

**April 15th Update** Prediction market platform Polymarket has kicked off a review of third-party startups in its Builders Program, launched last November to let external developers build trading apps on its infrastructure. Some 200 developers have joined so far, eligible for up to $2.5 million in grants and weekly rewards—but a key issue has emerged: top participants in the program are all building copy-trading apps. These apps curate trading accounts with abnormally high win rates, flag suspicious timing/trade amounts, and let users copy trades with one click. Kreo’s selling point is helping users “spot insider traders faster than others,” while Polycool lists an “Insider Trading Guide for Polymarket” on its site, noting: “This isn’t the stock market—betting on non-public info won’t land you in jail; decentralized prediction markets have totally different rules.” The Builders Program has driven Polymarket’s trading volume from $100 million last November to over $600 million in March, accounting for 16% of its monthly total. PolyGun (a copy-trading app) founder says its weekly volume once made up 11% of the platform’s entire trading. But security risks have surfaced: PolyGun was hacked via a code flaw in February, stealing ~$70k in user funds; another copy-trading app, Polycule, was previously hacked for ~$230k. Most copy-trading teams are anonymous, reachable only via Telegram—PolyGun’s press release lists three aliased executives, with operations run primarily by one person. Insider trading suspicions aren’t limited to copy-trading. On April 7, four accounts bet on a U.S.-Iran ceasefire and netted $663k. Blockchain firm Lookonchain found all four were created/funded the same day, with no prior transaction history. Last month, Polymarket partnered with Palantir to boost sports betting compliance and updated rules to ban trades using “stolen confidential info.” But it lacks user verification—many traders use VPNs to hide locations and switch accounts, making enforcement far harder than rival Kalshi (which requires authentication). Polymarket’s March volume hit ~$23 billion (10x last year’s same period) and is raising funding at a $20 billion valuation (up from $9 billion in October 2023). Kalshi raised $22 billion-valued funding in March. Both face scrutiny from U.S. state lawmakers, who argue prediction markets are illegal gambling services skirting state laws.