Ethereum spent years outsourcing its front-running problem to off-chain relays like Flashbots; the XRP Ledger is now proposing to fix the same problem in the protocol itself. On June 29, 2026, XRP Ledger co-founder and Ripple Chief Technology Officer Emeritus David Schwartz published a design called ReservedTxns, a native transaction-reservation scheme aimed at neutralising the sandwich attacks and front-running that a deterministic ordering rule makes possible on the ledger’s decentralised exchange (DEX) and automated market maker (AMM). It is a markedly different architectural bet from Ethereum’s off-chain Maximal Extractable Value (MEV) market — and the contrast is the story.
The vulnerability is structural. Because canonical transaction ordering on the XRP Ledger is set by a known, deterministic formula involving transaction hashes, a sophisticated actor can submit similar transactions repeatedly to raise the odds of landing in a favourable slot next to a target trade — the mechanical basis of a sandwich attack, as 24/7 Wall St. reported. Schwartz’s answer is a new ledger object, ReservedTxns, plus a TxnReserve transaction type that lets a trader claim a priority slot in an upcoming ledger before revealing the trade itself.
The parameters are specific. Per the proposal detailed by Cryptonews, a reservation must cost at least twice the standard transaction fee, the target ledger must be no more than 16 ledgers ahead of the current one, and each reserved object holds fewer than 32 transaction IDs unless later expanded. Reserved transactions execute first in their designated ledger and are then cleared to prevent repeat execution, a structure BeInCrypto notes is aimed squarely at sandwich-attack vectors. In effect, a trader pays a premium to hide intent until execution is already guaranteed — closing the window a bot needs to react.
The response layer is where XRPL and Ethereum diverge. Ethereum’s ecosystem converged on off-chain infrastructure — Flashbots, MEV-Boost and private mempools — that turned order flow into a competitive auction run largely outside consensus. Schwartz is proposing to keep the fix inside the protocol, where it is governed by validators rather than by a relay market. That has a cost: on the XRP Ledger, protocol changes require a validator supermajority to sustain support before an amendment activates, so ReservedTxns is currently a discussion draft, not live code. The governance bar that makes XRPL changes slow is also what makes them credibly neutral.
Notably, Schwartz himself has downplayed the urgency. “For the reasons I’ve explained, I’m not that concerned about this issue,” he wrote in the discussion, per crypto.news, framing the design as a precaution rather than a response to active exploitation. XRP traded near $1.05 as the proposal circulated, and the muted price reaction suggests the market is treating this as infrastructure hygiene rather than a catalyst — which is arguably the correct read for a change that must clear a validator vote before it touches mainnet.
The context that makes it matter is the ledger’s institutional ambitions. Ripple has spent the past year pushing the XRP Ledger as settlement infrastructure — from RLUSD stablecoin distribution to tokenised-asset rails — and front-running risk on a native DEX is precisely the kind of microstructure flaw that institutional desks scrutinise before routing size. The parallel to Ethereum matters here too: Uniswap v4’s rapid total-value-locked growth and the broader DEX build-out have kept MEV in the spotlight, and any chain courting institutional flow now has to answer the ordering question. It is the same scrutiny that shadows Uniswap’s own valuation debate.
What happens next is a governance question, not a technical one. The design gives the XRPL community a concrete path to review, but activation depends on validators — the same actors who greenlit prior amendments and who backed infrastructure moves such as the validator expansions seen elsewhere in settlement crypto. Watch three things over the coming weeks: whether other core developers endorse or contest the fee-and-window parameters, whether any live sandwich-attack evidence emerges to raise the urgency Schwartz has played down, and how the debate intersects with the CLARITY Act’s market-structure timeline, which will shape how seriously US institutions weigh XRPL’s DEX at all. If ReservedTxns advances, it becomes a test case for whether on-chain ordering can beat the off-chain MEV market Ethereum settled for.
This article is informational analysis only and is not financial, investment, or trading advice. Cryptocurrencies are highly volatile and can lose substantial value rapidly. Past performance and historical patterns do not guarantee future results. Do your own research and consult a regulated financial adviser before making any investment decision.
Karthik Subramanian
Karthik Subramanian is a founder, writer, and technology consultant with nine years in the crypto ecosystem. He covers token economics, L1/L2 infrastructure, DeFi protocols, wallets/custody, and the bridge between crypto and forex—broker technology, liquidity, and macro drivers. Karthik’s writing focuses on clear, practical frameworks that help professionals evaluate new products and on-chain innovation alongside FX market realities.
