How Walrus Uses Sui to Reserve Space & Enforce Storage Obligations
Walrus's integration with Sui goes beyond simple record-keeping. Sui becomes the enforcement layer that makes storage obligations real and verifiable.
Space reservation begins on-chain. A client wanting to store data first allocates storage capacity through a Sui smart contract. The contract debits the client's account and creates an on-chain object representing reserved space—a cryptographic right to store X bytes until time T. This object is the client's proof of prepaid storage.
When the client writes a blob, the PoA is linked to the storage reservation.
The Sui contract validates that the blob size doesn't exceed the client's reserved capacity and that the reservation hasn't expired. If checks pass, the reservation object is updated—remaining capacity decreases and the blob's lifetime is locked in.
Validators monitor Sui for valid PoAs. A validator that stores a blob without a corresponding valid PoA faces no economic incentive—they're holding data for which no payment exists. The on-chain contract is the validator's evidence that payment is real and locked.
Enforcement happens through periodic on-chain challenges. Smart contracts query validators: "Do you still have blob X from PoA Y?" If a validator claims to have it but cannot provide cryptographic proof, the contract detects misbehavior and initiates slashing. The validator's stake is seized proportional to the data loss.
This creates alignment. Clients pay upfront through reservations. Validators earn fees only by holding data successfully. The contract ensures payment is real and enforcement is automatic. Storage obligations transform from handshake agreements into on-chain smart contract execution.
Sui doesn't just record storage—it guarantees it.
