Legality in California
Both are CFTC-regulated event-contract platforms, legal in all 50 US states including California. Neither has a regulatory advantage over the other for California residents.
Markets and coverage
Sleeper covers game-level markets (winners, totals, spreads-as-probability) across NFL, NBA, MLB, NHL, and soccer. Chalkboard specializes in player props — individual player performance contracts — with the deepest coverage in the NBA and NFL. Sleeper's player prop coverage is growing but significantly narrower than Chalkboard's.
Pricing & fees
Both charge per-contract fees disclosed at order entry. Neither has a house margin. Effective cost is similar on comparable markets.
User experience
Sleeper's interface is fantasy-forward — your leagues and group chats are part of the experience. Chalkboard's interface is player-grid-focused — dozens of player lines visible at once, optimized for rapid prop trading during games. Different audiences, different designs.
Who should use which
Use Sleeper if: you want game-level trading, you already use Sleeper for fantasy, you want a social layer to your trades. Use Chalkboard if: you trade player props specifically, you follow individual athletes more than team outcomes, you want the deepest NBA and NFL prop coverage available.