Internet Computer contracts pay their own gas and get deleted if they run out

The Reverse Gas Model: Contracts Foot the Bill

Most blockchains put the cost of every interaction on the user. @dfinity's Internet Computer takes the opposite approach. Rather than requiring end users to pay a gas fee each time they interact with a smart contract, ICP places that responsibility on developers through what is called the reverse gas model. The result is a smooth, Web2-like experience: users do not need to obtain tokens, configure wallets, or sign and approve every transaction when interacting with a dapp on ICP.

Smart contracts on the Internet Computer are known as canisters. ICP tokens can be converted to cycles by burning them, and those cycles are used by developers to pay for installing canisters and for the resources they consume, including storage, CPU, and bandwidth. The cycle price is pegged to a basket of fiat currencies, so even as the market price of $ICP moves, the cost to developers of acquiring computational fuel remains predictable.

What Happens When Cycles Run Out

Keeping a canister funded is the developer's ongoing responsibility, and the protocol has clear rules for what happens when they fall short. If a canister runs out of cycles entirely it will be uninstalled, but a freezing threshold acts as a safety buffer: once the cycles balance dips below that threshold, the canister stops processing new requests while continuing to reply to existing ones. The default freezing threshold is set at the equivalent of 30 days of estimated runway, giving developers time to top up before any data is lost.

A canister will freeze execution and preserve state at a certain cycles threshold, and will be wiped when cycles run out completely. At that point, the code and all stored data are deleted, and only the canister's unique identifier is retained, per ICP documentation.

The model has broader implications for how decentralised applications are built and sustained. It enables fully on-chain decentralised applications without external hosting infrastructure, and users can interact through standard browsers or mobile apps without requiring crypto wallets or transaction fees. For developers, it means treating cycle balances as an operational cost to monitor and manage, much like a cloud computing bill.

Sources
Internet Computer: Fee Breakdown and Gas Cost Documentation
Internet Computer: Managing Canisters and Freezing Thresholds
Internet Computer: Tokenomics Overview