rosterOS Best Ball Overlay

Best Ball draft overlay for Underdog and DraftKings: live player grades, roster guidance, stack analysis, and exposure tracking.

rosterOS is a free best ball draft assistant for Underdog Fantasy and DraftKings. It overlays live player grades, market ADP, custom rankings, stack analysis, and portfolio exposure right inside your draft room — so you make faster, sharper picks on the clock without switching tabs, opening a spreadsheet, or doing mental math. Every available player is graded in real time against YOUR roster and the live board — not a static cheat sheet. As picks come off the board, grades, badges, stack signals, and roster feedback update instantly. Built for NFL best ball drafters who care about every second on the clock. LIVE PLAYER BOARD Search, filter by position (QB / RB / WR / TE), and sort by Rank, Grade, or ADP. An A+ to F letter grade on every player, priced against market ADP, roster fit, and tournament upside. Value and Reach pills show at a glance whether a pick is a bargain or a stretch versus ADP. Optional board columns: exposure %, average draft position (full-season and last 14 days), Team / Division / Playoff / Week 17 correlation, and combo ownership. Expand any row for a deeper card — rank, ADP, projection, bye week, draft %, and stack context. BADGES THAT CATCH WHAT YOU'D MISS STK — the pick completes a same-team stack with a QB or pass catcher already on your roster. LEV — flags the leverage handcuff sitting behind a starting running back. QB — this player's quarterback is still on the board, so you can take the pass catcher now and back-stack the QB later. Bye — warns when a pick lands on a bye week you're already heavy at. STACKS, BUILT IN Your active stacks grouped by team, across QB+WR, QB+TE, WR+WR, and more correlation types. Available QB stack targets that pair with the pass catchers you already own. Back-stack candidates — take the QB now while his receivers are still on the board. Stack strength rated High or Moderate so you know which correlations are worth reaching for. ROSTER TRACKING Emerging Build — the draft pattern your roster is forming, in plain language. Capital by Position — where your picks are going, and where you're over- or under-invested. Roster View — your ADP value and league rank across every pick. Portfolio Combos — how your player pairings compare to the field so you can spot chalk and find leverage (Chalk Heavy / Balanced / Unique Heavy). FORMAT-AWARE GRADING rosterOS detects the tournament you're drafting and grades for how it actually pays out: Season + Playoffs — balanced floor and ceiling, tilted toward late-season upside. Survivor — every single week matters; consistency and floor are king. Weekly Prizes — weekly ceiling is everything; favor upside and correlated stacks. Playoff-week and Week 17 correlation, weekly ceiling, and roster balance are baked into every grade — not bolted on afterward. Override the detected format anytime. TUNE IT TO YOUR STYLE Strategy Preference — set positional tendencies per position (Zero RB, Hero RB, Robust RB, Elite QB, Late-Round QB, Double WR Start, and more). Rank Trust — how much your grades lean on your custom ranks vs market ADP (Very Low to Very High). Stack Aggressiveness — how hard the engine pushes correlation (Off to Heavy). Playoff Stacking and Week 17 Boost — dial up the weeks that decide tournaments. Capital Penalty — how much roster concentration is punished in the grade. CUSTOM RANKINGS Upload a rankings CSV with Name and Rank columns, for Underdog, DraftKings, or both. rosterOS reports exactly which names matched each site's board, so nothing silently misses. When your rank and the model disagree on a player, the board shows both numbers side by side. Players not in your file keep rosterOS ranks. Replace or clear anytime. PORTFOLIO SYNC & EXPOSURE Underdog: while you're signed in, rosterOS picks up your session automatically — no password — and pulls your full draft history in one click. DraftKings: signed in, one click syncs your best ball entries using your existing session. No credentials are ever stored. Filter by tournament type to focus your exposure, or upload an Exposure CSV instead, and re-sync anytime after new drafts. See your live exposure % right on the draft board so you never accidentally double up on the players and pairs you already own. WHY BEST BALL DRAFTERS USE ROSTEROS The pick clock is short — rosterOS puts grades, ADP, stacks, and exposure in one place so you're deciding, not guessing. Value and reach calls get easy when the context is right there on the board. Stack and back-stack windows are flagged automatically, so you never miss a correlation. Your portfolio exposure is built in, so you can see when you're doubling up on pairs you already have. Playoff upside and Week 17 leverage are priced into your build from round one. HOW IT WORKS Opens automatically when you join an Underdog or DraftKings best ball draft. Reads the live board — including each site's own ADP — and applies your preferences in real time. Updates grades, badges, stack signals, and roster feedback as picks happen. GETTING STARTED Install rosterOS and pin it to your Chrome toolbar. Open the popup and run through the quick onboarding. Join any Underdog or DraftKings best ball draft and the overlay appears automatically. Use the Player Board, Stacks, Roster, and Draft Preferences tabs during your pick windows. If the overlay doesn't show up, refresh the draft tab and confirm Overlay Enabled is on in the popup. FREE AND PRIVATE Free to use — no account required. Your session and draft data never leave your browser. Everything is processed locally on your device. Your Underdog session token lives only in session storage and is deleted automatically when you close your browser. Preferences and uploads are stored in extension storage, not on any server. rosterOS is built for Underdog and DraftKings best ball drafts. It is not affiliated with, endorsed by, or sponsored by Underdog Fantasy or DraftKings.