--- # System prepended metadata title: Geth Overview --- ## Introduction **Geth**, which is the short form for Go Ethereum, is a **Go** implementation of the **Ethereum protocol** designed to allow developers run **nodes** on the Ethereum network, interact with the Ethereum Blockchain, validate transactions, and also execute smart contracts. Key features of Geth include: * Ethereum Node Implementation. * JSON-RPC API methods. * Smart Contract Execution (EVM Support). * Sync Modes. ## Core Functionality ### Ethereum Node Implementation. An Ethereum node is made up of two parts: * The **execution client** that handles transactions and smart contracts, * The **consensus client** that ensures the blockchain stays in agreement (consensus). Geth is an **execution client** that is coupled to a consensus client to keep track of the Ethereum blockchain. It is responsible for handling transactions, managing states and supporting the Ethereum Virtual Machine EVM. | Component | Role | |--------------------|----------------------------------------------------------------------------------------------| |**Geth (Execution Client)** | Executes Ethereum transactions, manages state, and provides RPC APIs for developers| |**Consensus Client** | Ensures the node follows the correct chain by handling consensus and syncing blocks | #### Sync Modes Syncing is the process that updates Geth to the latest Ethereum block and current global state. A Geth node is synced by various means depending on the **speed, storage requirements** and **trust assumptions**. To properly sync, Geth connects to a consensus client, especially now that Ethereum uses **proof-of-stake**. | Sync Mode | Description | Use Case | Pass Command | |------------------|-------------------------------------------------------------------------------------------------|----------------------------------------------|--------------------------------------------------------| | **Snap (Default)** |starts from recent block and syncs from there to the head of the chain,it keeps only the most recent 128 block states in memory. | Default mode, suitable for most users. | `--syncmode snap` | | **Full** |A full block-by-block sync generates the current state by executing every block starting from the **genesis** block. | High trust, validation-focused nodes. | `--syncmode full` | | **Archive** | Retains all historical data right back to **genesis**. | Querying **historical state data** instantly.| `--syncmode full --gcmode archive` | ### JSON-RPC API Developers interact with Geth by sending requests to specific **JSON-RPC API** methods. The RPC requests are sent to the node and the response is sent to the client using **transport protocols**. These RPC methods are grouped into various categories, depending on their functions. Meanwhile, all method names are made up of the **namespace**, an **underscore**, and the actual **method name** within the namespace. The `eth_call` method for example resides in the `eth` namespace. **Transport Protocols** Geth allows developers interact with the blockchain using three types of communication methods, called transport protocols. They are: **IPC**, **HTTP** and **Websockets**. | Transport | Direction | Good For | Default Port | Enable With | | ------------- | ---------- | ------------------------------ | ------------ | ------------ | | **IPC** | Local environment | Fast, secure (Unix systems) | N/A | Auto-enabled | | **HTTP** | One-way | Most common, tools & browsers | `8545` | `geth --http` | | **WebSocket** | Two-way | Event subscriptions, real-time | `8546` | `--ws` | ## Running & Configuring Geth ### Installation Geth can be installed via the following methods: * Package managers * Downloading a pre-built bundle. * Docker container. * Build from source code. #### Package managers **macOS (via Homebrew)** The easiest way for developers to install Geth is to use the **Geth Homebrew tap**. To check if Homebrew is already installed, run the command: ``` brew -v ``` If it returns a version, Homebrew is already installed. If it doesn't, [install Homebrew](https://brew.sh/). After installing Homebrew, run the following command to install Geth: ``` brew tap ethereum/ethereum brew install ethereum # Stable version brew install ethereum --devel # Latest dev version ``` To update Geth, run the following command: ``` brew update brew upgrade brew reinstall ethereum ``` **Ubuntu (via PPA)** Install Geth on Ubuntu-based distributions using built-in launchpad **PPAs** (Personal Package Archives). To add Ethereum PPA, run the following command: ``` sudo add-apt-repository -y ppa:ethereum/ethereum sudo apt-get update ``` To install Geth, run the following command: **For stable version** ``` sudo apt-get update sudo apt-get install ethereum ``` **For dev version** ``` sudo apt-get update sudo apt-get install ethereum-unstable ``` **Windows** The easiest way to install Geth on windows, is to visit the Geth [Downloads](https://geth.ethereum.org/downloads) page and download the Windows installer or ZIP file **Install Geth**: * The **install wizard** offers the user the option to install Geth, or Geth and the developer tools * Run the **installer** and follow the **prompts**. * The installer adds `geth` to your system's `PATH` automatically. * Alternatively, you can extract the ZIP file and run `geth.exe` from the command prompt. To update Geth, download and install the latest version using the steps above. Note: Use `geth --help` in the command prompt to view available commands. **FreeBSD via pkg** Geth can also be installed on FreeBSD via the package manager `pkg`. To download and install Geth, enter the command: ``` pkg install go-ethereum ``` This installs Geth software and the following developer tools: `clef`, `devp2p`, `abigen`, `bootnode`, `evm`, `rlpdump` and `puppeth`. To update an existing Geth installation to the latest version, enter the following command: ``` pkg upgrade ``` **FreeBSD via ports** Geth can also be installed using ports, by navigating to the `net-p2p/go-ethereum` ports directory and running `make install` as root: ``` cd /usr/ports/net-p2p/go-ethereum make install ``` This installs the Geth software and the following developer tools: `clef`, `devp2p`, `abigen`, `bootnode`, `evm`, `rlpdump` and `puppeth`. The binaries for these tools are saved in `/usr/local/bin/`. #### Downloading a pre-built bundle The easiest way to install Geth is by downloading a pre-compiled binary for your operating system. Follow these steps: * Go to the official Geth [downloads](https://geth.ethereum.org/downloads) page * Select your OS (Windows, macOS, Linux). ### Configuration & CLI Flags Geth is controlled using the **command line**. To start Geth, use the `geth` command. To stop Geth, press `ctrl-c`. Geth can be configured using command-line options called flags. **Common Flags** ``` --syncmode value – Syncing strategy (snap, full, fast, or light). Default: "snap". --http - Enable the HTTP-RPC server. --datadir value – Data directory for the databases and keystore. --verbosity value – Logging verbosity (0=silent, 1=error, 2=warn, 3=info, 4=debug, 5=detail). ``` To get command-line help, run: ``` geth --help ``` For a comprehensive list of CLI options, refer to the Geth [Command-Line Options](https://geth.ethereum.org/docs/fundamentals/command-line-options). ## Security **Security Best Practices** Securing and maintaining your Geth node is important to ensure the integrity of your operations and the broader Ethereum network. Here are essential security best practices: * Download Geth using only the links on the [Downloads](https://geth.ethereum.org/downloads) page. * Avoid exposing Geth API endpoints to the internet. * Ensure to keep private keys and account passwords backed up and inaccessible to adversaries. * Make use of [Clef](https://geth.ethereum.org/docs/tools/clef/introduction), a standalone key manager to manage private keys. Clef requires manual approval for transactions, reducing the risk of unauthorized operations. ## Conclusion By adhering to best practices, such as implementing proper firewall rules, regularly updating software, and securely storing keys, users can maintain a healthy and secure Geth node while contributing seamlessly to Ethereum’s decentralized ecosystem. For more details, refer to the official Geth [documentation](https://geth.ethereum.org/docs).