Launching a token

There are two ways in, and they differ only in whether the creator buys in the same transaction.

Use launchAndBuy if the creator wants tokens at all. A separate buy afterwards is a race against everyone watching the chain, on a pool that opens at its lowest price.

launchAndBuy needs the router to be the factory's launchForwarder. It can be switched off in an emergency, so check GET /v1/protocol → launchAndBuy.enabled before offering it. Plain launchToken keeps working either way.

TokenParams#

All limits are in UTF-8 bytes, not characters, so an emoji in a name costs four.

creatorFeeBps has no default worth relying on. Leaving it at zero is outside the bounds and reverts CreatorFeeOutOfBounds, so a launch can never land on a rate nobody chose.

The ticker#

Symbols are unique because HyperCore tickers are. Whoever lands first owns the ticker for good. These are reserved and can never be used: HYPE, USDC, USDT, USDE, USDH, PURR, BTC, ETH, SOL, UBTC, UETH, USOL, HFUN. The owner can reserve more.

Check before you show a form:

const free = await client.readContract({
  address: FACTORY, abi: factoryAbi, functionName: "isSymbolAvailable", args: ["MINE"],
});

GET /v1/launch/symbol?symbol=MINE gives the same answer with a reason: ok, invalid, reserved or taken.

The salt and the token address#

The token address is CREATE2, salted with keccak256(abi.encode(deployer, salt, creatorFeeRecipient, creatorFeeBps, launchConfigId)), and the metadata is part of the creation code. So:

• your salts are your own, and nobody can land a launch at an address derived from your account;
• an address commits to exact terms, so a vanity salt only works for the recipient, tranche, config and metadata it was mined for.

Do not compute the address by hand. Call deployer.predictLaunchAddress, or POST /v1/launch/predict with a session, which also returns the pool key and floor price so you can draw the token before it exists.

For a holder-rewards launch, use a fresh salt every time. A distributor's address depends only on creator, salt and quote, so reusing one reverts HolderRewardsDistributorTaken.

expectedEconomics#

The digest is:

keccak256(abi.encode(quoteToken, startingTick, tickSpacing,
                     protocolFeeBps, creatorFeeBps, maxInternalPriceImpactBps, launchFee))

previewLaunchEconomics(configId, creatorFeeBps) computes it. If any input moves between your read and your transaction, the launch reverts with LaunchEconomicsMismatch(expected, actual).

Metadata cannot be fixed later#

Everything on the token is permanent. The contract has no setter, and the name and symbol must never change because Elysium's bridge keys a token's mirror on them. Check spelling, the ticker and the logo before you sign.

What can change is creatorFeeRecipient: the current recipient can hand it on with factory.transferCreatorFeeRecipient(token, newRecipient). The creator tranche itself is frozen.

Common reverts#

CreatorFeeOutOfBounds comes from the hook, so a client holding only the factory ABI sees the raw selector 0x87ab5572. Decode with the combined tartarus.json from the ABI page, or look any selector up on the Errors page.