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Intro /

Icon LinkFuel Glossary

Icon LinkAddress

An address is a cryptographic hash representing an identity of a wallet or a predicate root.

Icon LinkAssetId

An asset ID is a unique identifier for an on-chain asset. It is derived from the root of the bytecode of the contract minting the asset.

Icon LinkBase Asset

The base asset is the underlying asset needed to perform any transactions on a blockchain. It is used to pay gas for transactions. On Ethereum, the base asset is ETH.

Icon LinkBlock

A block is a record of many transactions, that are grouped together and cryptographically hashed. The linked blocks form a chain, also called a blockchain.

Icon LinkBlock Explorer

A block explorer is an interface for block and transaction data produced by a blockchain. You can use a block explorer to explore and verify addresses, contracts, and transaction histories.

Icon LinkBlock Height

The block height refers to the total number of valid blocks produced in the history of a blockchain, starting with the genesis block.

Icon LinkBlock ID

A block ID is a unique identifier for a particular block.

Icon LinkBridge

A bridge is a mechanism that allows the transfer of data or assets from one blockchain to another.

Icon LinkBytecode

Bytecode is machine-readable code, usually generated from a compiler.

Icon LinkChain

Another name for a blockchain.

Icon LinkChainId

A unique ID for a blockchain.

Icon LinkClient

The Fuel client refers to the software that runs the Fuel Virtual Machine. It can be used to validate and produce blocks, and send transactions.

Icon LinkCoinbase

Coinbase refers to the validators paying themselves for processing a block from the transaction fees. Having a coinbase transaction on each block makes this process transparent to all users.

Icon LinkConsensus

The consensus layer defines the state and validates that all nodes on the blockchain have the same state.

Icon LinkConsensus Parameters

Consensus parameters are the rules used by clients to determine the validity of and finalize a block.

Icon LinkContract Call

Calling a contract means invoking a function from a smart contract that has been deployed to the blockchain.

Icon LinkContract ID

The contract ID is a unique identifier for a contract derived from the root of the contract bytecode.

Icon LinkData Availability

The data availability layer ensures that block data has been published to the network.

Icon LinkEIP

EIP stands for Ethereum Improvement Proposal. It refers to a proposal to upgrade the core software powering the Ethereum blockchain.

Icon LinkEOA

EOA stands for Externally Owned Account. It refers to a wallet address that is not controlled by a contract.

Icon LinkEVM

EVM stands for Ethereum Virtual Machine, which is the virtual machine used for the Ethereum network.

Icon LinkExecution

Execution refers to the processing of transactions by nodes in a network.

Icon LinkFaucet

A faucet is a service that provides free tokens for a testnet.

Icon LinkForc

Forc is short for Fuel Orchestrator. Similar to Cargo for Rust, Forc is the build system and package manager for Sway. It is used to build, test, and deploy Sway contracts.

Icon LinkFraud Proof

Fraud proofs are a blockchain verification mechanism whereby a claim on a new block is accepted unless a proof the claim is invalid is provided within some configurable time window. Both the Fuel protocol and the FuelVM are designed to be fraud-provable in restrictive environments such as the Ethereum Virtual Machine.

Icon LinkFuel

The Fuel blockchain.

Icon LinkFuels

Fuels is the name of the Fuel Rust and Typescript SDKs used to interact with a contract, similar to ethers.js or web3.js

Icon LinkFuelup

Fuelup is the official toolchain and package manager for the Fuel toolchain.

Icon LinkFuelVM

The FuelVM is the virtual machine powering the Fuel blockchain.

Icon LinkFuel Core

fuel-core is the name of the Fuel client implementation.

Icon LinkGas

Gas is a variable fee charged by a node to process a transaction that is executed on-chain.

Icon LinkIndexer

An indexer is a program that watches and organizes blockchain data so it can be easily queried.

Icon LinkInput

An input refers to a transaction input, which is a UTXO consumed by a transaction.

Icon LinkLayer 1 (L1)

Also called a level 1, this refers to a base layer blockchain that is not built on top of any other blockchain.

Icon LinkLayer 2 (L2)

Also called a level 2, this is a blockchain that is built on top of another blockchain. Layer 2 networks can offer unique benefits like allowing for cheaper transactions or sovereign rollups that can fork without forking the base layer.

Icon LinkLight Client

A light client is a client that doesn't validate blocks and transactions but still offers some functionality to send transactions.

Icon LinkLocked Wallet

A locked wallet is a wallet that can only interact with read-only smart contract methods.

Icon LinkMainnet

Mainnet refers to the main network of a blockchain, as opposed to a testnet.

Icon LinkMerkle Tree

A Merkle tree is a data structure which uses a cryptographic hash function recursively to condense a set of data into a single value, called the root. It allows efficient proofs that a given element is part of the set.

Icon LinkMessage

A type of input that only includes specific metadata, and is often used for bridging.

Icon LinkMint

Minting refers to the creation of new coins.

Icon LinkModular

Referring to a blockchain architecture that allows for execution, settlement, consensus, and data availability to run on separate layers.

Icon LinkMonolithic

Referring to a blockchain architecture that handles execution, settlement, consensus, and data availability all at the same time on a single layer.

Icon LinkNative Asset

With Fuel any contract can make its own native asset. On Ethereum, the only native asset is ETH. This allows for much cheaper token transactions because it doesn't require any contract state changes. It also allows you to directly forward any asset in a transaction call, avoiding the need for the approve and transferFrom mechanisms.

Icon LinkNetwork

Another name for a blockchain.

Icon LinkNode

A client that validates and produces blocks for the network.

Icon LinkOptimistic Rollup

An optimistic rollup is a sidechain that uses fraud proofs to verify transactions instead of relying on a majority of validators to be honest.

Icon LinkOutput

An output refers to a transaction output, or which UTXOs are output by a transaction.

Icon LinkParallel Transactions

Parallel transactions refers to the ability of the FuelVM to process multiple transactions in parallel.

Icon LinkPredicate

A predicate is a pure function that can return true or false, and is sent inside a transaction as bytecode and checked at transaction validity time. If it evaluates to false the transaction will not be processed, and no gas will be used. If it evaluates to true, any coins belonging to the address equal to the Merkle root of the predicate bytecode may be spent by the transaction.

Icon LinkPrivate Key

A cryptographic key that is used to prove ownership by producing a digital signature. It should be kept private (or secret) as it can grant access to a wallet.

Icon LinkPublic Key

A cryptographic key that is generated from its associated private key and can be shared publicly. Addresses are derived from public keys.

Icon LinkReceipt

A receipt is a data object that is emitted during a transaction and contains information about that transaction.

Icon LinkReentrancy attack

A type of attack in which the attacker is able to recursively call a contract function so that the function is exited before it is fully executed. This can result in the attacker being able to withdraw more funds than intended from a contract.

Icon LinkRollup

A rollup is a scaling solution for layer 1 blockchains that "rolls up" or batches transactions as calldata.

Icon LinkScript

A script is runnable bytecode that executes once on-chain to perform some task. It does not represent ownership of any resources and it cannot be called by a contract. A script can return a single value of any type.

Icon LinkSettlement

Settlement refers to how and where on-chain disputes are resolved or settled.

Icon LinkSidechain

A sidechain is a blockchain that runs independently but is connected to another blockchain (often Ethereum Mainnet) by a two-way bridge.

Icon LinkSignature

A cryptographic signature from a wallet, usually in reference to a signature for a message.

Icon LinkSmart Contract

Also referred to as a contract, a smart contract is a set of programming functions with persistent state that is deployed on a blockchain. Once deployed, the contract code can never be changed or deleted, and anyone can access public functions without permission.

Icon LinkState Channel

State channels allow for users to conduct any number of off-chain transactions while only submitting two on-chain transactions to open and close the channel. This reduces the number of on-chain transactions needed, which reduces the cost and saves time.

Icon LinkSway

Sway is the official programming language for Fuel. It is a domain-specific language crafted for the FuelVM and inspired by Rust.

Icon LinkTestnet

Testnet is short for test network. You can use a testnet to deploy and test contracts for free.

Icon LinkToolchain

A toolchain is a set of related tools. The Fuel toolchain includes fuelup, forc, fuel-core, and fuels.

Icon LinkTransaction

A transaction is any interaction with the blockchain, for example sending coins from one address to another.

Icon LinkUnlocked Wallet

An unlocked wallet can interact with both read and write smart contract methods.

Icon LinkUTXO

UTXO stands for unspent transaction output.

Icon LinkUTXO Model

A UTXO model is a blockchain model that doesn't keep track of account balances. Instead, it uses inputs and outputs to manage state, which allows for fast parallel transactions.

Icon LinkValidator

A validator refers to a network validator or node. Validators help validate transactions and produce blocks.

Icon LinkWitness

A witness refers to the cryptographic signatures from actors involved in authorizing a transaction, including the transaction signers, contract callers, and block producers.

Icon LinkZero-Knowledge Proof

A method that allows for the verification of secret information without revealing the secret.

Icon LinkZero-Knowledge Rollup

A rollup that uses zero-knowledge proofs to verify transactions. In ZK rollups, each rollup block posted to the contract must be accompanied by a validity proof (a succinct proof that the block is valid), which is also verified by the contract. Blocks are thus finalized immediately, and withdrawals can be processed in the same Ethereum block.