Monad, an EVM-compatible blockchain, activated its MonadTen revision on mainnet on September 2 at 14:30 UTC. The MIP-8 upgrade fundamentally changes how the network charges contracts for reading storage, replacing slot-by-slot gas accounting with page-based pricing.
Under the new system, storage is organized into pages of 128 consecutive words, totaling 4,096 bytes each. The first read from any page costs 8,100 gas, while subsequent reads within that same page cost 100 gas for the duration of the transaction. When a read crosses into a new page boundary, the cost resets to 8,100 gas.
Testing on mainnet block 101672712 confirmed the pricing model: reading slot 0 cost 8,100 gas, reading slot 1 on the same page cost 100 gas, and reading slot 128—the first slot of the next page—cost 8,100 gas again. This represents a 98% cost reduction for consecutive reads within a single page compared to the previous system, where each untouched slot cost 8,100 gas individually.
Storage Layout and Compatibility
Common Solidity data structures automatically benefit from the discount. Sequential state variables, struct fields, and array elements occupy consecutive slots, making repeated reads more likely to stay within a warmed page and share the reduced cost.
Mapping keys, which generally resolve to dispersed storage pages, do not inherit the discount automatically. However, struct fields stored under a mapping key remain contiguous and can share page-level savings.
Hashed or unaligned storage retains the existing cold baseline cost. Reads that cross page boundaries cost 8,100 gas each, and savings depend on how many slots a transaction accesses and whether those slots cluster within the same 128-slot boundary.
Developer Implications
MIP-8 preserves EVM execution semantics while changing the assumptions underlying developer tooling. Access list builders, storage proof formats, and gas estimation tools must adapt to the page-based model. The specification identifies contracts that hardcode storage opcode gas costs as the primary compatibility risk.
For developers, the incentive is straightforward: data read together becomes cheaper when stored close together.
