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Gas waiver

Governance-approved addresses (called waivers) submit a wrapper transaction that carries the user's signed payload and executes it at gasPrice = 0. The user holds no USDT0 and pays no gas. Stable operates one such waiver as a hosted service; partners can also register their own waiver addresses through validator governance.

How it works

Gas Waiver uses a wrapper-transaction pattern:

  1. The user signs an InnerTx with gasPrice = 0. The user's signature is preserved end-to-end; the waiver cannot modify the payload without invalidating it.
  2. A waiver wraps the InnerTx into a WrapperTx sent to a protocol marker address (0x000000000000000000000000000000000000f333) with value = 0, gasPrice = 0, and the signed InnerTx as its data payload.
  3. Validators detect the marker, check the waiver's authorization and policy constraints, and execute the inner transaction under the user's identity (from, nonce, call semantics).

Gas accounting is handled inside the waiver mechanism. The user pays nothing; the wrapper pays nothing; validators absorb the cost against the per-waiver policy.

Authorization and policy

Waivers are controlled by validator governance, not application logic. Governance provides:

  • Reviewable registration: every waiver address is registered on-chain and visible in state.
  • Revocation: validators can remove a misbehaving waiver at any time.
  • Scoped access via AllowedTarget: each waiver is bound to a specific set of target contracts and method selectors. The protocol rejects any wrapper whose inner to address and method selector fall outside that scope.

A valid wrapper transaction satisfies all of the following:

  • WrapperTx.to == 0x000000000000000000000000000000000000f333 (the marker address).
  • WrapperTx.from is a waiver registered on-chain via governance.
  • WrapperTx.gasPrice == 0 and InnerTx.gasPrice == 0.
  • WrapperTx.value == 0.
  • InnerTx.to and the extracted method selector are permitted by the waiver's AllowedTarget policy.

If any condition fails, validators reject the wrapper without executing the inner transaction.

Security model

  • User signature integrity: the user signs the InnerTx. The waiver cannot mutate the payload without invalidating the signature. Partners are still responsible for ensuring the user signs only the intended payload.
  • On-chain authorization: authorization lives on-chain. Only governance-registered waiver addresses can produce a valid wrapper submission, regardless of where the request originates.
  • Service-availability boundary: when partners route through Stable's hosted Waiver Server, submission availability depends on the service. The protocol-level authorization guarantees are unaffected.

When to use Gas Waiver

Gas Waiver fits any flow where the end user shouldn't have to hold USDT0 for gas:

  • Consumer apps onboarding users who have no stablecoin balance yet.
  • Agent-driven flows where the agent's wallet funds the gas.
  • Enterprise payment rails where the operator absorbs network costs.

For flows where the user does hold USDT0 but wants to bundle multiple calls into one signed transaction, see EIP-7702 delegation instead.

Next recommended

  • Enable gas-free transactions — Integrate the hosted Waiver Server API with API-key submission and NDJSON responses.
  • Gas waiver protocol — Read the full protocol spec: marker routing, wrapper format, governance controls.
  • USDT as gas — Understand the gas token that the waiver covers.