Optimism Mainnet Introduces Stake-Based Transaction Prioritization for Four-Week Experiment

According to official Optimism announcements, the OP mainnet is introducing its first-ever adjustment to transaction ordering rules today. For many years, the sequencer has exclusively used a "highest priority gas fee first" mechanism; now, a new stake-based priority ordering option is being added. This experiment, approved by Optimism’s governance body earlier this month, will run for four weeks (until June 23) and is optional for users. To participate, users must stake at least 100,000 OP in the PolicyEngineStaking contract. The experiment will proceed in two phases: Phase 1 (Week 1) uses a FIFO (first-in, first-out) ordering system, where staking above the minimum threshold does not affect priority. Phase 2 (Weeks 2–4) switches to a weighted priority gas multiplier mechanism based on staking duration—the longer the stake, the higher the priority. Transaction ordering for users who do not participate remains unchanged, with the PGA mechanism continuing as usual.