Yes. It runs in your browser on phone or PC, with no download and no payment. An account is optional and only saves your rank and record across devices.

Is StackDraft made by Ubisoft?

No. StackDraft is an unofficial fan game made by TOPFRAG. It is not affiliated with or endorsed by Ubisoft.

How are the odds worked out?

The simulator plays 100,000 rounds of your five operators against the algorithm's five on that bomb site, using operator data checked against the wiki, Ubisoft's patch notes and creator videos. Your win chance is how often your stack wins, sharpened so a better draft wins clearly more often. The result is one roll on those odds, so upsets can still happen.

How does ranked work in StackDraft?

Ranked uses rank points (RP). After 5 placement matches you get a rank from Copper to Champion (Copper 1000, Bronze 1500, Silver 2000, Gold 2500, Platinum 3000, Emerald 3500, Diamond 4000, Champion 4500 RP). Winning as the underdog pays more, and a good draft softens a loss. The algorithm gets sharper as your rank rises.

What is the Daily Draft?

One round a day, the same draft for every player, on a site picked for the day. Your score goes on the day's board, and playing on consecutive days builds a streak with bonus XP. It resets at midnight UTC.

How to play StackDraft

StackDraft is a free browser game for Rainbow Six Siege players. You draft a five-operator stack against an algorithm that counter-drafts you, then a simulator plays 100,000 rounds to set your odds and plays one round out. Best of three, on real Siege maps and bomb sites.

A match, step by step

Coin flip. It decides which side you play first and who picks first.
Map and bans. A real Siege map is rolled. You and the algorithm each ban one attacker and one defender. Banned operators are out for both sides all match.
Site briefing. The bomb site with its breach walls, hatches and the official floor plan.
The draft. Snake order (1-2-2-2-2-1). On your pick you're offered three operators and keep one. Once a round you can Reroll your offers or Scout the algorithm's next offers, and once a match you get a Hint.
The algorithm counter-drafts. It tests its offers against your stack and usually takes the best one. In ranked it plays sharper as your rank rises.
100,000 rounds. The simulator plays your stack against theirs and shows your win chance and the matchups that decide it.
The round. One roll on those odds, played out with a kill feed. Sides swap, and the first to two rounds wins.

Modes

Casual: a looser algorithm, nothing at stake but XP.
Ranked: rank points from Copper to Champion, 5 placement matches, a demotion shield after a promotion, and the top 10 Champions get numbered badges.
Daily Draft: one round a day, the same draft for everyone, a daily board and streak XP.
Tutorial: a guided first round with a coach.

Tips

Answer the algorithm's picks: every operator page lists who counters who.
Read the site: hard breach walls, hatches and windows change which picks matter. See the map guides.
Ban the operator you least want to face on that map. Bans hold all match.
Combos count: operators that work together (like a hard breacher and someone who clears the denial) add up.

FAQ

What is StackDraft?: StackDraft is a free browser game for Rainbow Six Siege players. You draft a five-operator stack against an algorithm that counter-drafts you, then a simulator plays 100,000 rounds to set your odds and plays one round out. Best of three, on real Siege maps and bomb sites.
Is StackDraft free?: Yes. It runs in your browser on phone or PC, with no download and no payment. An account is optional and only saves your rank and record across devices.
Is StackDraft made by Ubisoft?: No. StackDraft is an unofficial fan game made by TOPFRAG. It is not affiliated with or endorsed by Ubisoft.
How are the odds worked out?: The simulator plays 100,000 rounds of your five operators against the algorithm's five on that bomb site, using operator data checked against the wiki, Ubisoft's patch notes and creator videos. Your win chance is how often your stack wins, sharpened so a better draft wins clearly more often. The result is one roll on those odds, so upsets can still happen.
How does ranked work in StackDraft?: Ranked uses rank points (RP). After 5 placement matches you get a rank from Copper to Champion (Copper 1000, Bronze 1500, Silver 2000, Gold 2500, Platinum 3000, Emerald 3500, Diamond 4000, Champion 4500 RP). Winning as the underdog pays more, and a good draft softens a loss. The algorithm gets sharper as your rank rises.
What is the Daily Draft?: One round a day, the same draft for every player, on a site picked for the day. Your score goes on the day's board, and playing on consecutive days builds a streak with bonus XP. It resets at midnight UTC.