ParlayLab

Parlays are sold as a fun way to chase a big payout, but the math is brutal: the sportsbook's edge compounds with every leg you stack. Most bettors have no idea what their implied probability actually is on a slip, let alone what their expected value is per dollar. ParlayLab is the tool that finally shows them.

The parlay builder is three leg slots — sport, market, pick, book odds, and the calculated implied probability sitting on each one. Add legs, edit legs, watch the combined odds, implied probability, stake, and payout update in real time. A right-rail "your edge" callout compares the user's fair odds against the market's — the percentage edge is the entire story in one number.

The EV breakdown page takes the same three-leg parlay and decomposes it. A horizontal bar chart shows each leg's implied probability. A payout distribution shows the two outcomes — win-all versus lose-any — with the dollar values stacked next to each. A side-by-side fair-vs-market chart lets the user see, leg by leg, where the book is taking their cut. KPI tiles surface combined odds, true probability, implied probability, edge %, EV per $100, and a suggested Kelly stake.

The "Build your parlay" walkthrough is the four-step pitch: pick legs, check implied probabilities, see your edge, decide your stake. Each step is shown with a styled HTML mockup of the ParlayLab UI for that screen.

Built as a static Astro 6 site with Space Grotesk headlines, Inter body, and JetBrains Mono numerals on tabular-nums. Lab-white background (#fafafa) with electric-violet (#7c3aed) accents, thin 1px borders, and pure inline SVG for every chart. Every page reads like a precision instrument.