extra info

Author: miiu96

docs/sdk-and-tools/rest-api/transactions.mdx

@@ -347,16 +347,36 @@ Example response for cross-shard transactions:
 
 `https://gateway.multiversx.com/transaction/cost`
 
+This endpoint is used to estimate the gas cost of a given transaction.
 
-:::note
-This endpoint estimates the **gas cost** of a transaction. Use this value to determine the appropriate `gasLimit` before sending a transaction.
+It performs a read-only simulation of the transaction against the current on-chain state, returning the number of gas units the transaction would consume if executed in that exact state.
 
-In the background, this endpoint simulates the transaction in a read-only environment to estimate its gas cost. Any resulting smart contract results and events will also be returned.
-:::
+💬 How it works:
+- The endpoint takes all transaction input fields (value, sender, receiver, data, chainID, etc.).
+- It executes the transaction in a sandboxed, non-persistent environment, meaning it simulates execution without affecting the actual blockchain.
+- It uses the current state of the network (including smart contract storage, balances, etc.).
+- It returns the estimated gas (txGasUnits) and may also return smart contract results and events triggered by the simulation.
+
+❓ How does it apply to smart contracts?
+
+For smart contracts, the endpoint simulates the contract call exactly as if it were executed live, including processing all logic, branches, and emitted events.
+The gas estimate reflects the computation and storage impact that would occur if the state remained unchanged at the time of actual execution.
+
+❓ How does it approximate the cost if the contract logic has variable gas usage?
+
+If a smart contract’s logic has branches or conditional execution that result in variable gas usage (e.g., depending on internal storage state, previous executions, etc.),
+the estimation will only reflect the gas used by the path taken during this particular simulation.
+
+❗ Why is providing the correct nonce important?
+
+Because the simulation engine mirrors real transaction behavior, it requires a valid and correct nonce to properly simulate the transaction. Using an outdated or incorrect
+nonce may lead to simulation failure.
+
+⚠️ Can the estimated gas differ from the actual cost?
+
+Yes. Since the blockchain state may change between the moment you call /transaction/cost and when the transaction is actually sent to the network, the real gas usage can differ.
+This is especially true for smart contract calls that depend on dynamic or mutable state.
 
-:::warning
-As the transaction is executed in a simulated environment, `providing the correct nonce is mandatory`.
-:::
 
 <Tabs
 defaultValue="Request"