How Robinhood Chain orders transactions

Robinhood Chain orders transactions by their arrival time at the sequencer. A fee does not change that order. This page quotes the official rule, explains what the priority fee does, compares the rule with the priority gas auction that Arbitrum One adopted in September 2026, and describes the compliance screening at the sequencer. All facts are as of 2026-10-25.

Robinhood Chain sequencer ordering: first come, first served

The Robinhood Chain sequencer orders transactions strictly by their arrival time. The official docs state: "Robinhood Chain utilizes a first-come, first-served sequencing model, where the order is determined strictly by the arrival time at the sequencer." [1]

Robinhood Chain is an Arbitrum Orbit chain, and one sequencer makes its blocks. The Robinhood docs give no block time. We measured a mean interval of 104.2 ms between blocks in Q3 2026 [8]. The Arbitrum docs describe how a first-come, first-served sequencer works: it "inserts transactions into a queue based on the order in which they are received and executes them accordingly, which eliminates the need for a mempool." [3] No public pool of pending transactions exists for a bot to read.

The sequencer returns a receipt within a second. The Robinhood docs list three stages [4]:

After the batch is posted, the order is fixed unless Ethereum itself reorganizes [4].

Robinhood Chain gas fees: the priority fee buys no position

On Robinhood Chain, the priority fee does not change the position of a transaction. The docs state: "Priority gas auctions do not exist here; consequently, increasing your fee will not shift your transaction ahead of others already in the queue." [2]

A Robinhood Chain fee has two parts: the cost to execute the transaction on the chain, and the cost to post its data to Ethereum. "Both components are bundled into the gas your transaction pays." [5]

The general Arbitrum FAQ says: "no priority fee is necessary for Arbitrum transactions. If a transaction includes a priority fee, the origin address of the transaction will be refunded at the end of execution." [3] The Robinhood docs do not say how Robinhood Chain treats a tip. Under the current rule, a tip buys no position, so set it to 0. If Robinhood adopts a priority gas auction, this advice changes.

Arbitrum One: Timeboost, the priority gas auction and the Fast Feed

Arbitrum One replaced Timeboost with a priority gas auction (PGA) on 24 September 2026, and added a paid Fast Feed [6][7]. The Arbitrum docs say that Arbitrum One "has used Timeboost since April 2025" [9].

Under PGA, "users bid for ordering by attaching a priority fee to each transaction." [9] The sequencer orders transactions by priority fee in short rounds. "On Arbitrum One, the block time B is 250ms and the proposed number of rounds per block K is 2, giving a nominal round length of 125ms." [9] Arrival time still matters at the edges: "Ties are broken by the arrival timestamp recorded when the transaction first reached the Sequencer." [9] Arrival time also decides which round a transaction enters.

The Fast Feed is "a paid, authenticated WebSocket stream that publishes each transaction as soon as the Sequencer has ordered and executed it, before the block that contains it reaches the standard sequencer feed." [10] It "does not give you a view into the mempool." [10] The comparison table in the docs gives the Fast Feed's availability as "Arbitrum One" only [10].

Will Robinhood Chain adopt a priority gas auction?

Robinhood has not announced a priority gas auction for Robinhood Chain. CoinDesk reported on 2026-10-09 that Robinhood Chain "is evaluating a transaction-ordering system that would allow users to pay a fee to prioritize certain trades", according to one person familiar with the matter [6]. "Robinhood declined to comment." [6] On the same day, TokenPost ran the headline "Robinhood Chain Keeps First-Come, First-Served Transaction Ordering", with no cited source [7].

The Arbitrum docs say that "PGA is available for activation on supported Arbitrum chains with priority fee collection and a PGA-capable Sequencer build" and that "Arbitrum chains can select the number of rounds based on their needs." [9] Robinhood Chain blocks are about 100 ms apart, not 250 ms, so its round length would not copy Arbitrum One.

If Robinhood adopted PGA, three things would change:

• Inside a round, the priority fee would decide the order, not arrival time.
• Arrival time would still decide ties and the round that a transaction enters.
• An early view of the feed would still show what happened, but a fast transaction could lose its place to a higher bid in the same round.

No Fast Feed for Robinhood Chain has been announced.

Under first come, first served, arrival time is the only lever

Under first-come, first-served ordering, a transaction goes ahead of another only if it reaches the sequencer first. Two delays decide that arrival:

• The time to see the state. A bot acts on the latest block. The sequencer feed shows each block as the sequencer emits it. A relay near the sequencer can deliver it before a typical provider. We measure the lead of FirstLight on every block, using the method on the measurement page; the figure on the home page is live.
• The time to reach the sequencer. FirstLight Submit sends signed transactions to the sequencer from AWS Ohio (us-east-2), in the sequencer's AWS zone. Colocation puts your own instance next to the relay, on private addresses.

FirstLight does not change how the sequencer orders or includes transactions. It changes when you learn what the sequencer did, and how far your transaction travels [11].

Compliance screening can exclude a transaction

Robinhood Chain screens transactions at the sequencer, and it excludes a transaction that is associated with a sanctioned address. The docs state: "any transaction associated with a sanctioned address will be excluded from inclusion." They add: "Since a blocked transfer is never processed, it simply appears as though the event never occurred." [2]

"Robinhood Chain runs ArbOS 61." [12] The Arbitrum compliance-filtering feature "is available through the ArbOS 61 upgrade, however off by default." [13] The Arbitrum docs describe two cases [13]:

• A transaction sent to the sequencer. The rules engine "simulates each transaction before it is sequenced. If a transaction violates any compliance rule, it is rejected at the Sequencer level and never included in a block."
• A transaction forced in through the Delayed Inbox on Ethereum. If its hash is registered as restricted, "the transaction is forcibly failed on inclusion, consuming any gas attached to prevent spam."

The Robinhood docs do not say which parts of this feature Robinhood Chain enables.

FAQ

Sources

All pages fetched on 2026-10-25.

1. Robinhood Chain docs, overview: docs.robinhood.com/chain/ (fetched 2026-10-25).
2. Robinhood Chain docs, differences from Ethereum: docs.robinhood.com/chain/differences-from-ethereum (fetched 2026-10-25). Quotes: the priority gas auction line, and "Robinhood Chain maintains compliance standards through sequencer-level screening. [...] any transaction associated with a sanctioned address will be excluded from inclusion. [...] Since a blocked transfer is never processed, it simply appears as though the event never occurred, ensuring indexers remain synchronized with the actual state."
3. Arbitrum docs, FAQ: docs.arbitrum.io/learn-more/faq (fetched 2026-10-25). Answers "Does Arbitrum have a mempool?" and "Do I need to pay a tip or priority fee for my Arbitrum transactions?".
4. Robinhood Chain docs, transaction finality: docs.robinhood.com/chain/transaction-finality (fetched 2026-10-25). Quote: "Ordering is now fixed — your transaction can only be reorganized if Ethereum itself reorganizes."
5. Robinhood Chain docs, gas and fees: docs.robinhood.com/chain/gas-and-fees (fetched 2026-10-25).
6. CoinDesk, Ian Allison, "Robinhood Chain considers technology that gives paying traders priority", 2026-10-09: www.coindesk.com/business/2026/10/09/robinhood-chain-considers-technology-that-gives-paying-traders-priority (fetched 2026-10-25). Quotes: "is evaluating a transaction-ordering system that would allow users to pay a fee to prioritize certain trades, according to a person familiar with the matter", "Robinhood declined to comment." and "on September 24, Arbitrum replaced its Timeboost transaction-ordering system with a new model, Priority Gas Auctions".
7. TokenPost, "Robinhood Chain Keeps First-Come, First-Served Transaction Ordering", 2026-10-09: www.tokenpost.com/news/technology/29195 (fetched 2026-10-25). It gives "replaced Timeboost on Arbitrum One on Sept. 24, 2026" and cites no source.
8. FirstLight analysis of Q3 2026, data read 2026-10-25: public RPC rpc.mainnet.chain.robinhood.com, 76,275,326 blocks from 2026-07-01T00:00:00Z to 2026-10-01T00:00:00Z (blocks 653,325 to 76,928,651); 92 days / 76,275,326 = 104.2 ms.
9. Arbitrum docs, priority gas auction: docs.arbitrum.io/how-arbitrum-works/priority-gas-auction/pga (fetched 2026-10-25).
10. Arbitrum docs, Fast Feed: docs.arbitrum.io/how-arbitrum-works/priority-gas-auction/fast-feed (fetched 2026-10-25).
11. FirstLight measurement method: first-light.stream/docs/measurement (fetched 2026-10-25); home page first-light.stream/ ("measured on every block and drawn live", fetched 2026-10-25); Submit: first-light.stream/docs/submit; colocation: first-light.stream/docs/colo; feed: first-light.stream/docs/feed (all fetched 2026-10-25).
12. Robinhood Chain docs, run a full node: docs.robinhood.com/chain/run-a-full-node (fetched 2026-10-25).
13. Arbitrum docs, compliance filtering: docs.arbitrum.io/launch-arbitrum-chain/configure-your-chain/advanced/compliance-filtering (fetched 2026-10-25).