Stake $5–$100. Hit your goal, get it back. Miss, your friends collect. The commitment device with real teeth.
18+ · Available in every country Stripe supports · Not a chance-based game
No chance involved
There's no random outcome, no house edge, no draw. You either follow through on the promise you wrote or you don't.
You decide whether you win
Every promise is set by you, judged by you and the friend witnesses you choose. Promise doesn't pick winners or set odds.
A 20-year-old idea
Behavioural economists call these “commitment devices” and have been studying them since the 1990s. The model is well understood — we just made it one tap.
Product tour
Four taps from idea to a real-money commitment. Here's every screen you'll see.
Step 1 of 3
What do you promise?
01 · Write your promise
One sentence. Pick a category and a deadline. Done in 10 seconds.
Step 2 of 3
Skin in the game
Your stake
$20
Held by Stripe. Charged only if you break the promise.
02 · Put cash on it
$5–$100. Card held by Stripe, never charged unless you slip.
Day 5 of 7
Run 3x this week
“5k along the river — splits negative.”
03 · Show your work
Photo, text or screenshot. Your friends see it. The streak lives on the receipts.
Promise kept.
Run 3x this week · 7-day streak
04 · Stake comes back
Kept it? Hold is released, no fee. Broke it? Witnesses split the pot.
How it works
No habit tracker. No journalling. No willpower. Just stakes.
"Run 3x this week." "No doomscrolling after 10pm." Set a deadline, pick who holds you to it, decide if you want to challenge a friend to do it with you.
Your card is held (not charged) via Stripe until the promise resolves. A small processing fee covers Stripe's costs and is disclosed before you confirm.
Keep your promise and your stake comes back. Break it and your friends split the pot (minus our 15% platform fee). Streaks, badges, and a weekly leaderboard come for free.
How your money is handled
You're putting real money on the line. Here's exactly where it goes, who touches it, and how you get it back.
Payments are processed by Stripe (the same processor used by Lyft, Shopify and Substack). We never see your card number and Promise can't move money without your authorisation.
When you make a promise, Stripe places a hold on your card for the stake amount. Nothing is debited until the promise resolves. Keep it and the hold simply expires.
If you break your promise, the stake is split between the witnesses you chose when you set it up — not us, not strangers. Promise keeps a 15% platform fee, disclosed up front.
Challenge a friend and they decline? Cancel before the deadline? The hold is released in full. No partial fees, no “processing” surprises.
Promise is open to anyone 18 or older in countries supported by Stripe. Stakes are person-to-person transfers between friends, similar to Venmo or Splitwise — not gambling, not a contest, and not a regulated wager. See our Terms and Privacy Policy for the full picture.
Why it works
We didn't invent any of this. Behavioural economists have been saying it for decades. Promise just makes it one-tap easy.
Losing $20 feels roughly twice as bad as winning $20 feels good. That’s loss aversion — the single strongest behaviour nudge we’ve got. Promise puts real money on the line so your future self can’t quietly opt out.
Goals you tell friends about are 2–3× more likely to stick. Goals with money attached stick harder. Promise stacks both so there’s nowhere to hide.
Vague check-ins let you lie to yourself. Daily photo, text, or screenshot evidence doesn’t — and your streak lives and dies by the receipts your friends can actually see.
Free to join. Takes 60 seconds. 18+ only.
Not ready? and we'll ping you on launch day.