On-chain integration

For code that signs transactions or reads the chain directly. Same on Base and Robinhood Chain against each chain’s contracts; differences are marked. Indexed data only? Use the REST API.

Trading

Pools live in the canonical Uniswap v4 PoolManager with a custom fee hook. Wallets cannot call the PoolManager directly; trade through the router.

// SwapRouter - exact-in only. Approve the input currency first.
function swap(PoolKey key, bool zeroForOne, uint256 amountIn, uint256 minOut, address to)
    returns (uint256 amountOut)
// zeroForOne: false = buy the token, true = sell it - when the token is currency0.
// A B20-mode token can be currency1, and then the two are swapped.

The PoolKey

Field	Value
`currency0`	the launched token - it sorts below its pair on every launcher except B20 mode, where it can be either side
`currency1`	the pair token - `pairToken` in the API record
`fee`	`0` on V7 pools, `3000` on every other launcher, B20 mode, Robinhood Chain and Arc
`tickSpacing`	`60`
`hooks`	the token’s own hook - `curve` in the API record

A pool’s identity includes its hook, and Base alone has ten hooks with pools on them. Assume one hook for every pool and the other launchers’ swaps never match your pool ids - those tokens chart flat while trading normally.

Three things every integration must handle

	Rule	Source of truth
The tax is inside the swap	quote `minOut` with at least the direction’s rate of headroom or it reverts	`buyTaxBps` / `sellTaxBps` in the API record, or `AdvancedFeeHookV6.taxFor(PoolKey, bool zeroForOne)`
A fresh launch may be tolled	for up to 30 min, buys can pay a rate decaying from 99% to the buy tax. Sells never.	`taxFor` returns the live decayed rate - quote from it, not from the stored rate
Max wallet reverts oversized buys	surface as reduce size, not a generic failure	oversized sells near launch price revert `CurrencyNotSettled` - the sell floor

Launching programmatically

Base - AdvancedLauncherV6
Robinhood Chain - RhLauncher

struct LaunchParams {
    string  name;
    string  symbol;
    uint256 supply;
    string  metadataUri;
    address creator;
    address pairToken;
    uint256 marketCapUsd;
    uint16  buyTaxBps;        // each capped at 1000
    uint16  sellTaxBps;       // independent of buyTaxBps
    uint16  burnBps;
    uint16  liquidityBps;
    uint256 buyPair;          // dev buy, in pair-token units
    uint16  maxWalletBps;
    uint16  rewardsBps;
    uint64  vestCliff;        // seconds
    uint64  vestDuration;     // seconds; 0 = no vault
    uint32  sniperWindow;     // seconds, 10-1800; 0 = no toll
    uint16  sniperStartBps;   // must exceed buyTaxBps
    PayoutBasket basket;
    bytes32 salt;
}
struct PayoutBasket {
    address[] tokens;
    uint16[]  weights;
    address[] issuers;        // for ecosystem tokens
    uint16    vaultShareBps;
    bool      renounceBasket; // freeze in the launch transaction
}

launchDirect and launchGated take the same fields with startSqrtPriceX96 in place of marketCapUsd.

	Pair	Basket assets
Vetting	none - any ERC-20 the gate can price through a route	must pass `RoutedQuoteGate.isVetted` (or `isVettedBy` with the matching `issuers` entry)

launchGated is how a creator-chosen pair launches: usdPerPair(token, route) verifies the route hop by hop and prices the opening. The API’s gatedroute discovers a route for any address. The basket menu: basket-assets.

// RhLauncher.launch(LaunchParams p, Payee[] payees)
// Every field as Base's, in the same order, except the basket:
struct PayoutBasket {
    address[] tokens;
    uint16[]  weights;
}

No issuers, vaultShareBps or renounceBasket - there is no basket seat to describe. marketCapUsd bounded $250 - $15,000. Every basket asset must pass RhPairRegistry.isAdmitted, the same predicate that admits the pair.

The token’s creation code differs (a different compiler profile). A salt mined against Base’s AdvancedLaunchToken bytecode predicts an address the Robinhood launcher never creates and reverts TokenMustSortBelowPair. Mine against the 4663 build.

Rule	Enforced by
The CREATE2 salt is bound to the caller: `keccak256(abi.encode(msg.sender, salt))`	a mempool copier cannot deploy your address first
`vestDuration > 0` requires `buyPair > 0`	`VestRequiresDevBuy`
A vested dev buy skips the 10% cap	the whole buy routes into the vault

The basket controller seat

Base - HolderRewards
Robinhood Chain - RhHolderRewards

function setBasket(address[] tokens, uint16[] weights) external
function transferBasketControl(address to) external
function renounceBasket() external            // one way

function setBasket((address asset, uint16 weightBps)[] slots) external
function setController(address c) external   // to a burn address to freeze

Find the distributor from the token’s rewardTracker() or the API’s rewardsDistributor.

`setBasket` enforces
Slots	1 - 10; empty arrays mean back to pair currency
Weights	sum to exactly 10,000 bps; none zero
Assets	no duplicates, no zero address, never the launch token
Vetting	none on rebuilds - an unroutable slot pays the pair instead

Readable state: basketController, basketRenounced, basketSize(), basketSlot(i) (token, weight, holdings). Every call reverts once renounced. Value in a replaced slot drains to holders on the same maths.

Watching the chain

Event	From	Carries
`AdvancedLaunched(token, creator, poolId, pairToken, sqrtPriceX96, buyTaxBps, sellTaxBps, burnBps, liquidityBps, payees)`	the launcher	everything to build the PoolKey and index from block one
`RewardsEnabled(token, distributor, rewardsBps)`	the launcher	the dividend distributor
`VaultCreated(token, vault, beneficiary, vestCliff, vestDuration)`	the launcher	the vesting schedule, when there is one
`FeeTaken(poolId, currency, platformFee, creatorFee)`	the hook	every taxed swap’s fee flow

AdvancedLaunched has two shapes, and backfilling the full history needs both. V6, V7, B20 V6B and RhLauncher on Robinhood Chain and Arc emit the split-tax shape above, topic0 0x370377cb17f063e0544347d821ef4fb78fb513351700977cb06c7e63715d1ef0. The launchers before V6 (V2 to V5C and B20 V1) emit one taxBps in place of buyTaxBps and sellTaxBps, topic0 0x508e31622f2b7886bd54a544c43d38ad441276dd8b24f0fb37e7c793869f6997. Match on the launcher’s address as well as the topic: other projects emit launch events with common names. The pool’s key is in the PoolManager’s Initialize in the same transaction, with id equal to poolId. Same events on all three chains - Arc runs the same launcher and hook code as Robinhood Chain - so one decoder serves every chain.

Decoding reverts

`HopTooThin` - not your fault

error HopTooThin(uint256 hop, uint256 usd, uint256 floorUsd)   // 0xb5377e60

The pair’s pricing route is too thin for the feed to answer honestly. Raised by a contract the launcher calls, so decode against the routed-feed ABI or match 0xb5377e60. Nothing in the tuple fixes it - retrying, lowering the buy or changing the cap all revert the same way. Check the pair first: the API reports a refusing feed, and the form blocks it. It reopens by itself when liquidity returns.

The others

Revert	When	Surface as
`CurrencyNotSettled`	an oversized sell near the launch price	reduce size
`DevBuyTooLarge`	unvested dev buy over 10% of supply	lower it, vest it, or raise the cap
`VestRequiresDevBuy`	`vestDuration > 0`, `buyPair == 0`	a lock needs something to lock
`TaxTooHigh`	a tax field over 1000 bps	10% per side is the ceiling
`MarketCapOutOfRange`	the cap is outside the launcher’s band	the ranges
`TokenMustSortBelowPair`	the mined address sorts above the pair	re-mine; on 4663, against the 4663 bytecode
`PairNotAdmitted` (4663)	a pair or basket asset fails `isAdmitted`	pick an admitted one

Start here

Launch a token

Trade and earn

Build on it

On-chain integration

Trading

The PoolKey

Three things every integration must handle

Launching programmatically

The basket controller seat

Watching the chain

Decoding reverts

`HopTooThin` - not your fault

The others

​Trading

​The PoolKey

​Three things every integration must handle

​Launching programmatically

​The basket controller seat

​Watching the chain

​Decoding reverts

​HopTooThin - not your fault

​The others

Trading

The PoolKey

Three things every integration must handle

Launching programmatically

The basket controller seat

Watching the chain

Decoding reverts

`HopTooThin` - not your fault

The others