Hyperliquid Aims to Challenge Polymarket? Zero Trading Fee Enters $63.5 Billion Prediction Market

April 30th — Decentralized exchange Hyperliquid unveiled its "Outcome Tokens" fee structure, a key milestone ahead of its mainnet launch as it gears up to go head-to-head with top prediction markets Polymarket and Kalshi. The core feature of the fee design: zero fees to open positions; fees only apply when closing or settling trades. Traders using the platform’s "quote alignment tokens" get extra perks: 20% lower taker fees and 50% higher maker rebates. The full fee schedule is now accessible to developers. Outcome Tokens rolled out under the HIP-4 upgrade proposal, letting users trade binary real-world event contracts in the same account as Hyperliquid’s existing perpetuals and spot positions. The timing is strategic: Polymarket just announced this week that "perpetual trading is coming soon," setting up direct competition between the two. For context, the prior upgrade — HIP-3 — launched permissionless perpetual contracts in October 2025; trading volume from those contracts already makes up over 35% of the platform’s total volume. The prediction market space is booming: industry trading volume jumped over 300% year-over-year in 2025 to $63.5 billion. Right now, Outcome Tokens are still in testnet; the mainnet launch date hasn’t been set yet.