Bonding-curve launchpads on BNB Chain: buying before and after graduation
How four.meme, Flap and Genius.fun price a new token on a curve, what graduation moves to PancakeSwap, the fees involved and what changes for you as a trader.
Most new tokens on BNB Chain do not start life in a normal liquidity pool. They start on a launchpad, where a contract sells the token along a price curve until enough has been raised. Then the token "graduates" and its liquidity moves to a DEX. Launchpads such as four.meme, Flap and Genius.fun work this way.
If you buy on a launchpad, you are trading against a formula, not against other liquidity providers. Knowing that formula, and what happens at graduation, tells you a lot about the price you get.
What a bonding curve is
A bonding curve is a contract that sets a token's price from how much of it has been sold. Buying pushes the price up, selling pushes it down. Binance Academy's explainer on bonding curves describes linear, exponential and other shapes.
Flap documents its curve openly. It is a constant-product formula with virtual reserves:
(x + h) × (y + r) = K
Here x is the number of tokens left in the curve, y is the quote currency raised (BNB, for example), and h and r are virtual amounts that set the opening price. The Flap documentation points out the key difference from a normal pool: nobody can add liquidity to the curve. Its depth is fixed by those parameters.
A worked example with real parameters
Flap publishes the parameters it uses for tokens priced in BNB on BNB Chain: r = 6.14, h = 107,036,752 and K = 6,797,205,657.28. It warns that the table may change and that each token's own parameters should be read from its contract, so treat what follows as an illustration of the shape.
Every Flap token has a supply of one billion. Plugging the numbers in, before Flap's 1 % trading fee:
| Tokens sold | BNB in the curve | Price vs the opening price |
|---|---|---|
| 0 | 0 | 1.0× |
| 100 million | 0.61 | 1.2× |
| 250 million | 1.79 | 1.7× |
| 500 million | 5.06 | 3.3× |
| 700 million | 10.56 | 7.4× |
| 800 million | 16.00 | 13.0× |
Two things follow. Early buyers get far more tokens per BNB: before the fee, 1 BNB at the very start buys about 155 million tokens, while 1 BNB after 700 million have been sold buys about 23 million. And the curve is shallow in absolute terms. The whole curve holds only 16 BNB when it ends, so even small orders move the price noticeably. A 1 BNB purchase is a large trade on a curve like this.
Graduation: where the liquidity goes
Each launchpad defines its own finishing line and its own destination. As documented on 2026-10-01:
- four.meme. A token has a supply of one billion. When the curve completes, at roughly 18 BNB for BNB pairs, 20 % of the supply and all the collected funds are paired on PancakeSwap. Since 2025-03-31, the product update says graduated liquidity goes to PancakeSwap V2 and the LP tokens are burned.
- Flap. When 80 % of the supply has been sold, the remaining tokens and the whole reserve become DEX liquidity. On BNB Chain the destination is PancakeSwap, chosen at launch. Tokens without a tax go to a concentrated-liquidity pool where possible and fall back to a V2 pool. Tokens with a tax can only go to V2.
- Genius.fun. About 714 million of the billion tokens can be sold on the curve, and for BNB launches the curve completes at 15 BNB raised. The rest seeds a full-range PancakeSwap Infinity pool whose position is locked in a contract with no withdrawal function, according to its integration docs.
After graduation the curve stops trading. four.meme's contract emits a TradeStop event, and Genius.fun's curve reverts sells once it is complete, with its docs pointing holders to the new pool. From then on the token trades like any other, against pool liquidity.
Fees and other things that bite
Launchpad trades are not free, and the fees differ:
- four.meme charges 1 % per trade on the platform, with a minimum of 0.001 BNB.
- Flap charges 1 % of every buy and sell on BNB Chain while the token is on the curve. The fee stops at graduation.
- Genius.fun charges 2 % on curve trades, and its pool hook takes 2 % on swaps after graduation.
There is more to watch:
- Tax tokens. four.meme and Flap both let creators launch tokens with a tax of 1 %, 3 %, 5 % or 10 % on trades. On Flap, since its V5.4.0 release, the tax applies on the curve too, on top of the 1 % fee. A 10 % tax plus a 1 % fee means you start 11 % behind.
- Anti-sniping windows. Some launchpads charge very high fees in the first moments of a launch. Genius.fun's opening window lasts 15 seconds and starts at 97 % of the amount spent, halving fourteen times. four.meme's X Mode uses a fee that decreases block by block after creation.
- Creator allocations. On four.meme, creators can buy part of their supply in the launch transaction.
- Thin markets at both ends. The curve is small by design, and a freshly graduated pool holds only what the curve raised.
Before graduation vs after
| On the curve | After graduation | |
|---|---|---|
| Where you trade | the launchpad's own contract | DEX pools, PancakeSwap first |
| Price set by | the curve formula and tokens sold | pool balances, moved by every trader |
| Liquidity | fixed by the curve parameters | the seeded pool, plus anyone who adds |
| Fees | launchpad fee, plus any token tax | pool fee, plus any token tax or hook fee |
Buying through Tirio
Tirio routes through four.meme, Flap and Genius.fun curves alongside regular pools, so a buy can go to the curve or to a pool, whichever pays more for the amount. Curve prices are read from the launchpads' own contracts, and the quote you sign is simulated as the complete transaction before it reaches you.
There is one limit to know about. On four.meme, Tirio only buys tokens that are still on the curve. In our testing, a four.meme token cannot be transferred outside four.meme's own contracts before it graduates, so a sale has to go through four.meme itself. Once the token graduates, Tirio routes it through its PancakeSwap pool like any other token, in both directions.
Taxed launchpad tokens need extra slippage room. Our guide to taxed tokens explains why, and our token checklist covers what to look at before buying something brand new. The full list of venues Tirio routes through is at /bsc/protocols.