Combos
A combo puts 2 to 10 picks in one slip and backs them as one position. It pays only if every pick lands. With money it is a Polymarket Combo, exactly as Polymarket itself offers them: one position, one price from Polymarket for the whole slip. If any pick misses, the combo pays nothing.
How a combo works with real money
When your slip has two or more picks, Polymarket prices the whole slip. It answers in well under a second with one blended price for the whole set of picks, and the slip shows exactly what the combo pays if every pick lands, the price as odds, the combined chance it implies, and how long the price holds (a few seconds; the slip gets a new price when it runs out). Press Back and your own wallet signs one order; Polymarket fills it and you hold one combo position. Backd never prices a combo and never takes the other side.
The maths
The combined chance multiplies: 58% × 64% × 72% = 26.7% that all three land. Before a price comes in, the slip shows an estimate of stake ÷ that chance, clearly marked as an estimate: Polymarket sets the final price when you back it. Its blended price is the real combined chance you're getting; the position pays $1 a share, so $10 at a blended price of 30¢ buys about 33 shares and pays about $33.33 if every pick lands. Backd's 1% fee is inside the total shown.
The rules
One pick per match or event: picks from the same match move together (a home win makes “3 or more goals” likelier) and Polymarket rejects picks that contradict each other. Only combo-enabled markets can go in; the slip marks any that can't. The stake is for the whole slip, at least $1; Polymarket decides how big a combo it will price, and the slip tells you when it won't. The combined chance must be at least 0.001%, so take out a long shot if the slip refuses.
Every price is re-read on the server when the slip is checked, and the price expires a few seconds after it arrives, so sign promptly. If Polymarket declines at the last moment or the price runs out before you sign, nothing is charged and you get a new price.
How a combo settles
The combo position settles once every pick's market has resolved. If every pick landed it pays $1 a share into your wallet (the settle job claims it for you where it can; otherwise the combo page shows Claim, one signature). If any pick missed it pays nothing. A win earns XP of about 10 ÷ the combined chance, up to 1,000.
Building one
Tap a side on any market and it goes in your slip, which follows you round the site. The Combos page has a builder with search, filters and ready-made combos to start from. Or swipe one together in a minute.
A pick you've already backed on its own can go in a combo too: your bet's page and the Your position card on its market have Add to a combo. The combo is a new position with its own stake; the single bet stays as it is.