Who controls it
- Transaction ordering
- A centralized upstream sequencer orders transactions; the validity system has one whitelisted proposer and one whitelisted challenger.
- Escape hatch
- Users can force transactions through Ethereum after the sequencer window. But permissioned proof roles and an inactivity recovery that can take indefinitely long mean no independent withdrawal is guaranteed.
- Upgrade authority
- An X Layer multisig can execute immediate upgrades, with no window for users to withdraw. One critical implementation address was not source-verified at review.
- Halts and outages
- OKX announced a 2025 mainnet upgrade that temporarily suspended block production and all X Layer services. The later migration to an OP Stack and OP Succinct design improved the architecture without removing the single sequencer, permissioned proof roles, or instant upgrade control.
Ketju assessment
Ketju does not approve X Layer: OKX operates the only sequencer, whitelisted actors control proof proposal and challenge, and an operator multisig can change the system at once. These are three separate control dependencies. The planned suspension in 2025 showed that block production is within the operator’s control. Ethereum data availability and a forced-transaction path help. They do not give users a credible self-service withdrawal while proof recovery and upgrade authority stay permissioned.
Review triggers
- Revisit after proposer and challenger roles become permissionless
- Revisit after regular upgrades carry an enforceable on-chain delay of at least 7 days
- Revisit after every critical implementation is source-verified and inactivity recovery is practical
Each trigger names a fact anyone can observe. If one occurs, Ketju will review the assessment again. None is a forecast.
Questions before use
- Does the client’s thesis require censorship resistance, or primarily low-cost settlement?
- Can the client withdraw without help from the party that normally orders transactions?
- Who can upgrade bridges or contracts, and what delay applies?
- Does the asset introduce an issuer weaker than the chain grade?
- What evidence will show a halt, censorship event, or governance change?
Research sources
- OKX: X Layer migration from Geth to Reth · OP Stack migration, centralized sequencer, execution client
- OKX: X Layer mainnet upgrade commenced · operator halt, upgrade control
- L2BEAT: X Layer · permissioned proof roles, upgrade delay, source verification, forced transactions
We read these sources on 2026-08-19. The documents and the control facts can change. If a review trigger occurs, Ketju reviews the chain before its next scheduled date.