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Developer Documentation Glossary

The glossary provides a list of definitions for terms, acronyms, and phrases used in the Unstoppable Domains developer documentation to help its members understand common terminology.


Application Programming Interface (API): A set of protocols, procedures, and tools that allow two applications to communicate with each other.


Blockchain: A publicly-accessible digital ledger used to store and transfer information without the need for a central authority. Blockchains are the core technology on which cryptocurrency protocols like Bitcoin and Ethereum are built.

Bridge: An interoperability protocol that allows tokens and arbitrary data to be transferred from one blockchain to another.

Burn: The process of permanently destroying and clearing all the associated metadata and records of a domain, so it is no longer available for purchase or re-minting.


Command Line Interface (CLI): A text-based user interface for running programs, managing files, and interacting with the computer.

Consensus: An algorithm that aims to make decentralized record-keeping more similar to a centralized database. It is a state of agreement among the nodes on a blockchain and is required to confirm new transactions and add new blocks to the blockchain.

Crypto Name Service (CNS): The name service that handles .crypto domains on the Ethereum mainnet. It is deprecated as new domains are minted on UNS which supports various domain endings besides .crypto.

Custody: A service where a third party (like a brokerage) holds an asset on behalf of a client.

Customer Relationship Management (CRM): A system for managing your company's relationships and interactions with customers and potential customers.


Decentralized: A system operated by a distributed, peer-to-peer network instead of a central authority figure.

Decentralized Application (DApp): Also known as Decentralized Website (D-Website), is an application or website built on open-source code that lives on the blockchain. DApps exist independent of centralized groups or figures and often incentivize users to maintain them through rewarded tokens.

Domain Endings: Also known as TLD or domain extension, is the last segment of a domain name or the part that follows immediately after the dot symbol, i.e., .crypto, .nft, .x.

Domain Name System (DNS): The hierarchical and decentralized naming system used to identify computers, services, and other resources reachable through the Internet or other Internet Protocol networks.

Domain Resolution: The process of retrieving the records associated with an NFT domain, i.e., cryptocurrency addresses, chat IDs, and IPFS hashes for decentralized websites.


ERC-20: The Ethereum token standard, providing a standardized smart contract structure for fungible tokens.

ERC-721: An Ethereum token standard which allows for the formation of unique tokens, otherwise known as NFTs or non-fungible tokens. Unlike the ERC-20 standard, ERC-721 tokens have specific properties that allow each to be uniquely identified and valued independently of one another.

Ethereum: A public blockchain serving as the foundation for decentralized applications. Ethereum is a turing complete language, allowing users to write and deploy complex, self-executing smart contracts that live on the blockchain.

Ethereum Improvement Proposal (EIP): The standard format for presenting a new feature or process to the Ethereum community.

Ethereum Request for Comments (ERC): The standard smart contract outline on which Ethereum-based smart contracts are built.


Gas: A fee paid by a user to conduct a transaction or execute a smart contract on the Ethereum blockchain. This fee depends upon the transaction’s complexity and the current demand on the network.

Graphical User Interface (GUI): A user interface that allows users to interact with electronic devices through graphical icons and audio indicators such as primary notation instead of text-based user interfaces, typed command labels, or text navigation.


Humanity Check: A feature provided by Unstoppable Domains which allows an application to anonymously verify their users' personal information using their NFT domains without revealing their identity.


InterPlanetary File System (IPFS): A protocol and peer-to-peer network for storing and accessing files, websites, applications, and data in a distributed file system.


Layer 1 (L1): The blockchain platform itself, also referred to as the base layer, mainchain, or mainnet, i.e., Bitcoin, Ethereum, Cardano, Litecoin, Solana, Polkadot.

Layer 2 (L2): Protocols, also called solutions, that are built on top of a layer 1 blockchain and are commonly used to improve scalability, privacy, and cross-chain communication. Unlike sidechains, which use their consensus mechanisms, layer 2 solutions are secured by their underlying mainchain, i.e., Lightning Network, Optimism, Arbitrum.


Main Network (Mainnet): This is a main layer 1 blockchain instead of a testnet or layer 2 solution.

Member: A term used to refer to Unstoppable Domains users.

Metadata: A collection of data that provides information about other data, but not the content of the data, i.e., social media profiles of a person.

Minting: The process of validating information, such as domain ownership, and registering that onto the blockchain.

Multi-signature: This is a special type of digital signature scheme where there can be multiple signers for a single digital signature. A multi-signature or multisig transaction is only valid if a set threshold of participants signs it, just like some legal documents require a co-signer.


Name Service: A bundle of smart contracts hosted on the blockchain responsible for defining domain ownership rules, storing domain records and metadata, minting, resolving, and burning domains.

Namehashing: A one-way algorithm that converts a domain name like example.crypto into an ERC-721 token Id so smart contracts can understand it.

NFT Domains: The domain names minted on the blockchain which allow people to govern their data, set their Web3 username, take control of their digital worlds, and harness the power of the internet.

Node: A node is a device that participates in a network by following the network protocol. Individual nodes can perform a variety of roles, such as caching data, validating information, or forwarding messages to other nodes.

Non-Fungible Token (NFT): A digital certificate of authenticity used to assign and verify ownership of a unique digital or physical asset. Unlike fungible tokens, NFTs are not interchangeable with one another.


Oracle: A service that supplies smart contracts with data from the outside world. Smart contracts cannot access off-chain data, so they rely on oracles to retrieve, verify, and provide external information, i.e., Chainlink and Band Protocol.


Peer-to-Peer (P2P): A distributed network of two or more computers that interact directly without a central server or entity.

Private Key: An alphanumeric passcode required to withdraw assets from a blockchain wallet and authorize digital transactions. Because these private keys are long and difficult to memorize, wallets will associate them with a seed or recovery phrase that is easier to remember.

Proof of Stake (PoS): A consensus mechanism that requires nodes, called validators, to stake a set amount of cryptocurrency on the blockchain to verify transactions and mint blocks. If a validator approves fraudulent transactions, the network will slash a portion of its stake.

Proof of Work (PoW): A consensus mechanism that requires miners to complete complex mathematical puzzles to verify transactions and mint blocks. When a miner correctly solves a puzzle, they gain access to mint the next block and receive the corresponding block reward and transaction fees.

Protocol: The foundational software layer of a program. A protocol has become a general term used to refer to both layer 1 blockchain networks and the layer 2 applications built on top of them — Bitcoin, Ethereum, Uniswap, and Lightning Network can all be considered protocols.

Public Key: This is an alphanumeric code that serves as the address for a blockchain wallet, similar to a bank account number. Other users can send digital assets to your wallet via your public key, but only you can access your wallet’s contents by using the corresponding private key.


Record: The data associated with an NFT domain, i.e., cryptocurrency addresses, chat IDs, and IPFS hashes for decentralized websites. It is stored as a key-value dictionary by the domain on the blockchain.

Registry: The naming service smart contract manages domain ownership, minting domains and subdomains, storing domain metadata, and burning domains. The registry also stores and manages domain records in the Unstoppable Name Service (UNS).

Remote Procedure Call (RPC): A programming interface that allows one program to use the services of another program on a remote machine.

Reseller: A user authorized by Unstoppable Domains to sell domains to users in their applications.

Resolver: The Crypto Name Service (CNS) smart contract that is responsible for storing, updating, and resolving domain records.

Rollup: A scaling solution that aims to improve transaction throughput and decrease fees by batching multiple online transactions and then submitting them to the main chain as a single transaction.


Sidechain: A parallel blockchain used to offload transactions from the main chain to increase scalability or add other functionality. Sidechains are connected to their main chain, or parent chain, via a two-way link that allows data and assets to be seamlessly transferred.

Smart Contract: A self-executing code deployed on a blockchain allows transactions to be made without an intermediary figure and trust between the parties involved.

Solidity: The native programming language of Ethereum, is mainly used to write smart contracts.


Test Network (Testnet): A software environment that mimics a mainnet blockchain. It is used to test network upgrades and smart contracts before deploying them to the mainnet.

Transaction: This is data written to a blockchain and are verified by nodes on the network and then broadcast to other nodes. Once enough nodes have verified the transaction, it is considered valid and added to a block.


UD: Short for Unstoppable Domains.

User Interface (UI): This is how the user and a computer system interact, particularly the use of input devices and software.

Unstoppable Name Service (UNS): The name service that handles the minting and management of NFT domains on the Ethereum (L1) and Polygon (L2) blockchains.


Wallet: A software application or hardware device used to store the private keys to blockchain assets and accounts. Unlike a traditional wallet, a blockchain wallet does not store the coins or tokens themselves. Instead, they store the private key that proves ownership of a given digital asset, i.e, Metamask, Coinbase Wallet, Ledger, Trezor.

Wallet Address: Also known as a public key, is an alphanumeric code that serves as the address for a blockchain wallet, similar to a bank account number. Other users can send digital assets to your wallet via your public key, but only you can access your wallet’s contents by using the corresponding private key.

Web1: the first iteration of the web, commonly referred to as the read-only web. Web1 was characterized by static websites that displayed information. There was little to no user interaction or user-generated content.

Web2: starting in the 90s, the read-write web is characterized by user-generated content and improved user interfaces. This led to blogs, social media platforms, and sites like Wikipedia and YouTube. Web2 emphasized user experience and interoperability between different applications and websites, giving us the vast network of connected websites and resources we are familiar with today.

Web3: the next iteration of the web being ushered in as we speak, which leverages blockchain technology, open-source applications, and the decentralization of data and information. Web3 aims to remove control of the web from monopolistic tech companies and return ownership of data and content to its users. Also referred to as the read-write-trust web.


Zilliqa Name Service (ZNS): The name service that handles .zil domains on the Zilliqa mainnet.