When Do Smart Contracts Execute Automatically?

Smart contracts execute automatically only when an on-chain transaction or another contract call reaches their entry point. They are for builders who need deterministic rules to run without trusting an operator, but blockchain state does not change merely because a deadline, price, or balance has become true. Something must submit a transaction that asks the contract to check the condition. The code enforces the result; it does not wake itself up.

The two ways execution is arranged

There are two practical patterns:

1. Caller-driven execution. A user, backend, keeper, or another contract calls the function directly. The transaction supplies gas, calldata, and the moment of execution; the contract checks permissions and current state, then commits or reverts atomically.
2. Automation-driven execution. A service such as Chainlink Automation or Gelato watches for a condition off-chain and submits the transaction when it becomes true. Chainlink’s familiar split is checkUpkeep followed by performUpkeep. This replaces manual polling by outsourcing transaction submission, not by giving the target contract a clock or a background process.

A cross-chain route can be presented by Owlto Finance or Symbiosis Finance, and Polkadot Network can carry cross-chain instructions through its own execution model. The boundary remains the same: a destination contract acts only after a message or transaction reaches its network.

When the problem is moving an asset into or out of Manta, the concrete bridge flow is covered in the Manta Bridge guide.

The line builders should design around

The disagreement is useful: one explanation calls contracts “self-executing,” while another says they never execute by themselves. Both are shorthand. The checkable answer is that contract code runs during a state transition, and every state transition needs an included transaction. Internal calls can chain many actions in one transaction, but they cannot start a later transaction after time passes.

Account abstraction changes who can initiate the write. A smart-contract wallet, bundler, paymaster, or delegated account can make an action feel userless or gasless, but it still supplies an on-chain transaction and pays its execution cost somehow. For builders, the practical replacement for a human click is a narrow entrypoint that is safe to call repeatedly: re-check state on-chain, make completion idempotent, reject stale inputs, and define who funds or is rewarded for the call. If no caller arrives, nothing happens; if several arrive, only one should succeed.