You buy into a caper by sending XRD to its bonding curve from the buy panel on the caper’s own page. The curve mints you new tokens on the spot and sets the price itself, so there is no counterparty to find, no order to fill and no listing to wait for. The smallest buy the contract accepts is 0.001 XRD. What you get back is a token that carries three things a plain token does not: a claim on a treasury the group owns, weight in the votes that spend it, and a right to leave with your share.
What am I buying?
Tokens that did not exist until you bought them. A caper does not sell you inventory another holder is unloading – the curve mints against a fixed notional cap of 100,000,000,000 tokens, and your purchase moves circulation up that cap by however much your XRD pays for. The contract refuses any buy that would push circulation past the cap.
Holding those tokens is what makes you part of the caper rather than a spectator. The same balance is read three ways: as your stake in the treasury, as the multiplier on your voting weight, and as the amount you can redeem when you leave. There is no separate membership token to acquire and no application to be accepted.
How is the price set?
By a formula, not by a market. The price of the next token depends only on how much of the curve has already been sold. Writing s for the fraction in circulation – tokens sold divided by the 100bn cap – the marginal price is
P(s) = 0.001 × √s / (1 − s)
which starts near zero, rises as a square root through the early range, and steepens sharply as the curve approaches fully sold. Every buy advances s, so every buy raises the price for the buyer after you. That is the whole pricing mechanism: no order book, no market maker, no oracle, and nobody quoting a spread.
Because the price is a function of circulation, a large buy does not clear at one price. It walks up the curve as it fills, so the average you pay is worse than the price you saw before you pressed the button. That is slippage, and it is a property of the shape rather than a fee anyone charges.
Where does my money actually go?
Your XRD is split three ways before any of it prices your tokens:
- A trade fee off the gross. Governance sets the rate, and the contract caps it at 10%. Do not read a rate quoted anywhere as permanent – read the cap, which is the part the contract guarantees.
- The founder’s collateralization skim. A slice of what is left, taken partly in XRD and partly as a share of the tokens minted. This is the founder’s reward for launching, and it is deliberately front-loaded.
- The remainder into the reserve. Everything else lands in the curve vault, which is the pool that pays sellers and backs the token.
The skim is the part a buyer should understand before committing, because it is not flat. It is a straight-line taper: largest at s = 0, falling steadily, and exactly zero once 30% of the curve is in circulation. Past that point every buy is fee-split between the trade fee and the reserve alone, and the founder takes nothing further from new buyers. The contract bounds the peak too, so the founder’s share of the mint can never exceed roughly 5% however governance is tuned – that ceiling is peak × 1/3 × 30/31, and the remaining thirty-first of the token leg goes to the Commons treasury rather than the founder.
The practical reading: you pay the most to the founder for being early, and the earliest buyers pay it precisely because the reserve behind their tokens is thinnest.
Is my money safe? What backs the token?
Part of it is backed and part of it is not, and the split is a known number rather than a promise. At genesis a caper’s curve holds two thirds of its market capitalisation as XRD in the reserve vault. That is not a policy choice – it falls out of the curve’s shape. A curve priced as supply to the power n holds exactly 1/(n+1) of its capitalisation in reserve, and caper’s curve is a pure square root at the origin, so n = ½ and the fraction is 2/3.
The other third is a claim on buyers who have not arrived yet. If nobody else ever buys, that third is not there. This is the honest shape of any bonding curve and it is worth stating plainly rather than discovering later: the reserve can pay every holder the curve price at the current circulation, but it was never sized to pay every holder what the token is nominally worth.
What the reserve does guarantee is that the sell side always works. There is no scenario where you hold tokens and cannot find a buyer, because the curve is the buyer and the vault is already funded.
Can I sell, and how much do I get back?
Yes, at any time, and the amount is computed in closed form rather than negotiated. Selling walks the same curve backwards: the payout is the reserve required at your circulation before the sale minus the reserve required after it. There is one curve in both directions – no separate buy and sell price, no bid–ask spread – so the price you sell at is exactly the price the next buyer would have paid to reach that same point. A trade fee comes off the payout on the way out.
The consequence people underestimate: because you are selling back down a rising curve, selling into a caper that has grown since you bought returns more than you paid, and selling one that has shrunk returns less. Nothing about the mechanism protects you from that, and nothing about it depends on anyone else agreeing to trade with you.
Does buying make me a voter?
Buying makes you a member; it does not by itself give you weight. Caper’s vote weight is
w = (t × v) / (V × T)
where t is what you hold, v is how many votes you have cast, V is the total votes cast across the caper, and T is the tokens in circulation. Your holdings are a multiplicative factor, so a large balance genuinely counts for more – but so is your participation, and a zero anywhere in the numerator produces zero weight.
That has a consequence worth knowing before your first proposal: a member’s very first vote carries zero weight, because their vote count is still zero at the moment it is recorded. Weight is something you accumulate by turning up, and a holder who never votes never converts their balance into influence. Buying a large position the day before a contested vote does not buy the vote.
What are my ways out?
Two, and they pay from different pots.
Sell back to the curve. The route above. You are paid out of the reserve vault at the curve price, and the tokens return to inventory for the next buyer. Fast, always available, and it pays you nothing from the treasury.
Exit. The right the whole model is built around: you surrender your tokens and take a proportional share of the treasury the caper has accumulated. Your share is your vote weight – the same (t × v) / (V × T) – so the exit pays out on participation as well as holdings. Leaving a caper covers the mechanics in full.
The two are not alternatives to pick between at the moment you buy. They answer different questions: the curve answers “what is my token worth right now”, and the exit answers “what is my share of what we built”.
What buying does not give you
Stated plainly, because the gap between these and what a token sale usually implies is where people get hurt:
- No yield. Holding tokens pays nothing by itself. A caper’s treasury grows or shrinks by what its members vote to do with it.
- No claim on the founder. The skim is theirs once taken, and no mechanism claws it back.
- No guaranteed floor. The reserve backs the curve price at the current circulation, not the price you paid.
- No control proportional to money alone. Weight needs participation, per the formula above.
- No say in whether the caper does anything. A treasury sits until a proposal passes; see Paying someone from a caper’s treasury.
Will the price go up?
Nobody can tell you, this page will not try, and you should treat anyone who does tell you as selling something. The curve fixes what a token costs at a given circulation; it fixes nothing about whether anyone else will buy. A caper’s price rises when people buy and falls when they sell, and there is no emission schedule, no yield and no mechanism anywhere in the contract that pushes it in either direction.
So the question “how do I invest in a caper” is worth reframing before you act on it. What you can actually assess in advance is not a price path but three things that are all readable on-chain right now: how much XRD sits in the reserve behind the token, how much sits in the treasury the exit would pay out of, and whether the caper has ever passed a proposal and spent any of it. A group that has never executed anything has not yet shown it can turn money into work – which is the only thing that would make its treasury worth more than the XRD already in it.
How do I buy into a caper?
- Open the caper’s page from the roster on caper.network. Every caper has one.
- Connect a Radix wallet holding XRD. You need XRD for the purchase itself and a little more for the network fee.
- Enter an amount – at least 0.001 XRD – in the buy panel. The panel shows the tokens you receive at the current circulation.
- Sign. The tokens arrive in the same wallet, and you are a member from that transaction onward.
- Vote on something. It costs little and it is the only thing that converts your balance into weight.
Before you buy into any caper, read its treasury and its proposal history rather than its description. Both are on-chain and both are on the caper’s page – a caper that has never passed a proposal has never demonstrated it can spend what it has raised.
Where next
What is a caper covers the model itself, and Leaving a caper the exit right in full. For the pricing mathematics rather than the buyer’s view, see Bonding curve and Trading. If you are on the other side of this – launching rather than backing – start at Getting started. If you are reading this through an AI agent, Querying a caper from an AI agent documents the read-only MCP servers that expose a caper’s live treasury and proposal history.