Best ball analytics lab — visual portfolio analysis for Underdog Fantasy.
bblab is a Chrome extension that connects to your Underdog Fantasy account and gives you a full analytics dashboard for your best ball portfolio. Simulate lobby advance rates, visualize your draft value, track stacks, and analyze week 17 matchup exposures across all your entries.
- Value Map — bubble chart of your avg draft price vs current ADP, with best/worst value rankings
- Rosters — all your draft cards with archetype tags, luck scores, and lobby simulation
- Exposures — searchable player exposure table with headshots, WK17 matchup flags, and drill-down popups
- Stacks — team stack breakdown with partner frequency and week 17 pair detection
- Lobby Simulation — 3,000-iteration Monte Carlo simulation showing advance % for all 12 teams in a room
- Draft Luck Score — measures how far players fell to you vs ADP
- Week 17 Matchups — highlights correlated boom/bust pairs on your rosters
bblab is not yet on the Chrome Web Store. Install it manually in a few steps:
- Download — click the green Code button on this page → Download ZIP, then unzip the folder
- Open Chrome extensions — go to
chrome://extensionsin your address bar - Enable Developer mode — toggle it on in the top right corner
- Load unpacked — click the button and select the
bblabfolder you unzipped - The bblab icon will appear in your Chrome toolbar
- Visit app.underdogfantasy.com and log in
- bblab auto-detects your session — you'll see bblab ✓ appear in the top nav
- Click the bblab button → Open bblab →
That's it. No copy-pasting tokens required.
| File | Purpose |
|---|---|
manifest.json |
Extension config |
background.js |
Service worker — token storage and auto-refresh |
content.js |
Injected into Underdog — detects session and injects nav button |
app.html |
The full bblab app |
app.js |
All app logic — data fetching, rendering, simulation engine |
bbm_final_model.json |
Historical best ball model used for simulation |
chart.umd.js |
Chart.js for the bubble chart |
bblab-logo.png |
Logo |
icons/ |
Extension icons (16px, 48px, 128px) |
If bblab saves you some draft stress, feel free to buy me a coffee ☕
- bblab reads your Underdog data locally — nothing is sent to any external server
- Works with Best Ball Mania and other Underdog best ball tournaments
- Requires Chrome (or any Chromium-based browser like Brave, Edge)