The Chain
Robinhood Chain as the engine sees it. Verified against the chain, not taken from documentation.
Everything below was checked directly against Robinhood Chain rather than read off a blog post. Where a number came from somewhere else it says so and it carries a date, because chain statistics go stale fast and a confident stale number is worse than none.
The basics
| Chain ID | 4663 (0x1237) |
| Type | Arbitrum L2, mainnet since 1 July 2026 |
| Gas token | ETH, 18 decimals |
| Block time | ~100ms |
| Public RPC | https://rpc.mainnet.chain.robinhood.com |
| Explorer | https://robinhoodchain.blockscout.com, Blockscout with an open REST API |
A hundred millisecond block time is the fact that shapes everything else. It means roughly ten blocks a second, so any tool that polls the chain on a human interval is describing something that already happened a hundred times over.
There is no public mempool
This one surprises people, and it changes what is possible.
Subscribing to newPendingTransactions works. It connects, it acknowledges,
and then it delivers zero events while the chain mines around ninety
transactions a second. The same is true of Alchemy's own pending transaction
subscription. The sequencer includes transactions instantly, so there is no
waiting room for anything to sit in.
Pre block visibility exists, but only in one place.
The sequencer relay is not an RPC endpoint
wss://feed.mainnet.chain.robinhood.com looks like a WebSocket RPC and is not
one. It is the Arbitrum Nitro sequencer relay. It pushes raw sequenced batches
at anyone who connects, with no subscription step and no key, and
eth_subscribe against it does nothing at all.
That relay is the only signal on this chain that arrives before a block does. It is free, and it is free to anyone willing to decode the format. The engine reads it for two things, covered in Attribution.
Where the trading happens
Three generations of Uniswap run here at once, plus a long tail of other venues. Measured over a live sample rather than assumed.
| Venue | Share of swap transactions |
|---|---|
| Uniswap V4 | 62% |
| Uniswap V3 | 33% |
| Uniswap V2 | 5% |
| Curve, other AMMs, aggregators, pads | the remainder |
V4's dominance is the awkward part, because V4 does not behave like the others. Its pools live inside one singleton contract, it uses flash accounting, and most of its pools quote in native ETH rather than WETH. Native ETH emits no log when it moves. Coverage is the whole story.
Contracts worth knowing
All confirmed against the live chain and most of them verified by name on Blockscout.
| What | Address |
|---|---|
| Uniswap V4 PoolManager | 0x8366a39cc670b4001a1121b8f6a443a643e40951 |
| Uniswap V3 Factory | 0x1f7d7550B1b028f7571E69A784071F0205FD2EfA |
| SwapRouter02 | 0xcaf681a66d020601342297493863e78c959e5cb2 |
| WETH | 0x0Bd7D308f8E1639FAb988df18A8011f41EAcAD73 |
| USDG | 0x5fc5360D0400a0Fd4f2af552ADD042D716F1d168 |
| Multicall3 | 0xcA11bde05977b3631167028862bE2a173976CA11 |
WETH and USDG are what pairs quote in. USDG is the chain's dollar and the more common of the two on newer pools.
The V4 PoolManager holds no pool list
A V4 pool has no address of its own. The PoolManager hashes the pool key and
never stores it, so there is no getter that turns a poolId back into its two
currencies. The only place that mapping exists is the Initialize event, and
the poolId is an indexed topic on it, which is why the engine can resolve one
lazily with a single query rather than indexing hundreds of thousands of
pools up front.
Account abstraction is normal here
ERC-4337 and EIP-7702 are both in heavy use. In practice that means the address
that signed a transaction is often a bundler rather than a trader, and reading
tx.from as the trader would credit the bundler with everyone's profit.
The engine pulls the real account out of the UserOperationEvent instead. When
a bundle carries more than one account it is dropped and counted rather than
guessed at, because attributing a trade to the wrong wallet is a worse failure
than not attributing it.
Gas is subsidized, and that ends
Robinhood subsidized gas on this chain for ninety days from launch, which puts the end of it around 29 September 2026.
Worth holding in mind when you read anything on the board. Cheap gas makes some behaviour viable that will not be viable afterwards, including the kind of self trading that manufactures a track record. The cluster detection exists partly because of it.