Understanding Gas and Transactions
This module explains how transactions flow through the network, what gas is, and how the Ethereum Virtual Machine (EVM) executes smart contracts.
Gas, Transactions, and Blocks
Every transaction must pay gas to compensate miners/validators.
For EVM chains like Rootstock, gas is paid in rBTC.
A transaction flows through three steps:
- Submitted to the network
- Picked up by miners
- Included in a block
Transaction Components
| Field | Description |
|---|---|
from | Sender address |
to | Recipient address (or contract) |
value | Amount of rBTC to send |
data | Contract call data (if applicable) |
gasLimit | Maximum gas units to spend |
gasPrice | Price per gas unit |
Gas Calculation
Transaction Cost = Gas Used × Gas Price
If a transaction runs out of gas, it reverts but you still pay for the gas consumed.
EVM Overview
The Ethereum Virtual Machine (EVM) is a runtime environment for executing smart contracts.
Key concepts:
- Bytecode execution — Contracts compile to bytecode
- Storage, memory, stack — Different data locations
- Opcodes — Low-level instructions
- Contract ABI — Application Binary Interface for function calls
Rootstock is fully EVM-compatible, so Ethereum tools work with minimal or zero modification.
Bitcoin vs EVM Smart Contracts
Rootstock merges Bitcoin's security guarantees with Ethereum-compatible smart contracts.
| Feature | Bitcoin | EVM-Compatible Chains |
|---|---|---|
| Smart Contracts | Limited (Bitcoin Script) | Full Solidity support |
| Token Standard | None | ERC-20, ERC-721, etc. |
| VM | Bitcoin Script | EVM |
| Strength | Security, finality | Programmability |
Rootstock sits at the intersection: Bitcoin-backed security + EVM programmability.
Summary
Before moving forward, ensure you understand:
- How blockchains maintain shared state
- How keys, wallets, and addresses work
- What gas is and why it's required
- How the EVM executes smart contracts
Next: Rootstock Architecture