explore/docs/GLOSSARY.md

Ubiquitous Language Glossary

Domain terms used in the Blockscout frontend codebase. Intended for both engineers and agents. Terms are listed alphabetically within each section. Where a codename differs from the product name, both are shown.

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Architecture

Terms specific to how this codebase is structured. Read this section first when navigating the repo or ARCH_REDESIGN.md.

Term	Definition
Chain Variant	A non-rollup chain with custom UI or domain entities (e.g. Celo, TAC, SUAVE, MegaETH, ZetaChain). Grouped under features/chain-variants/<name>/. Distinct from a Rollup, which implies an L1/L2 settlement relationship.
Feature	An optional, config-gated product area (e.g. stats, marketplace, user-ops). Corresponds roughly to a flag in configs/app/features/. Lives under client/features/. Contrast with Slice.
Rollup	A chain that settles transactions on a parent (L1) chain. Introduces specific entities: deposits, withdrawals, transaction batches, output roots. Organized by rollup type under features/rollup/<type>/ (e.g. optimism, arbitrum, zk-sync). Contrast with Chain Variant.
Slice	A core explorer domain entity that is always present on any EVM chain, regardless of feature flags (e.g. tx, block, address, token). Lives under client/slices/. Contrast with Feature.

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Domain entities

Blockchain objects that appear as first-class UI elements — detail pages, list rows, API resources, stubs.

Term	Definition
Blob	An individual EIP-4844 data blob attached to a transaction. A single transaction can carry multiple blobs. Each blob has its own detail page (/blob/[hash]) and is a first-class entity in the UI (with its own components, API resource, and stub). The term "blob" remains correct for the entity — only the feature folder uses data-availability (see Data Availability).
CCTX (Cross-Chain Transaction)	A ZetaChain-specific transaction type that spans multiple chains. Displayed as a separate tab on the transactions list page. Unrelated to the general cross-chain transactions feature (interchainIndexer).
Dispute Games	Part of the Optimism Fault Proof System. On-chain games used to challenge and resolve disputed L2 output roots. Displayed in the rollup navigation when faultProofSystem is enabled.
Epoch	A consensus time period specific to Celo. Has its own index and detail pages in the UI. Not a generic blockchain concept in this codebase — always refers to a Celo epoch. Lives under features/chain-variants/celo/.
Interop Messages	Cross-rollup messages passed between OP Stack chains using the native interoperability protocol. Visible in rollup navigation when NEXT_PUBLIC_INTEROP_ENABLED is set. Distinct from Interchain Indexer messages. Currently in deprecated state.
Kettle	In the SUAVE architecture, a Kettle is a trusted execution environment (TEE) node that processes MEV bundles. Transactions on SUAVE are associated with a Kettle, and the UI exposes a per-Kettle transaction list at /txs/kettle/[hash].
Operation	A TAC-specific entity representing a bridge operation between the TON and EVM ecosystems. Has no equivalent on standard EVM chains. Exposed at /operations and /operation/[id].
User Op (User Operation)	An ERC-4337 account abstraction operation — a transaction-like object submitted to a bundler rather than directly to the network. Displayed in a dedicated list at /ops and detail page at /op/[hash]. Config-gated via NEXT_PUBLIC_HAS_USER_OPS.

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Features & integrations

Optional product areas and their backing services. Each corresponds to a folder under client/features/.

Term	Definition
Advanced Filter	A UI feature for filtering transactions using complex multi-criteria queries (address, method, token, amount ranges, etc.). Distinct from the basic filter controls present on most list pages. Config-gated via NEXT_PUBLIC_ADVANCED_FILTER_ENABLED.
Beacon Chain	The Ethereum Proof-of-Stake consensus layer. When enabled, exposes beacon chain deposits and withdrawals alongside regular transactions. Not a rollup — it is the Ethereum L1 consensus mechanism.
BENS (Blockscout Name Service)	Blockscout's own address naming service, chain-agnostic and operated by Blockscout. Distinct from ENS (which is Ethereum-specific). In the codebase also referred to as name-services or name-domains.
Clusters	An address identity and grouping service. Aggregates multiple addresses under a named cluster (individual, protocol, organization). Exposes a directory, leaderboard, and per-address lookup. Backed by the Clusters API (NEXT_PUBLIC_CLUSTERS_API_HOST).
Data Availability	The config-gated feature that surfaces Blob data posted to Ethereum (EIP-4844). data-availability is the name used for the feature folder and config flag — the underlying entity is still called a Blob. Config-gated via NEXT_PUBLIC_DATA_AVAILABILITY_ENABLED.
Fault Proof System	Optimism's mechanism for proving the correctness of L2 state transitions on L1 via Dispute Games. Enabled by the NEXT_PUBLIC_FAULT_PROOF_ENABLED feature flag.
Flashblocks	MegaETH's sub-second block streaming mechanism. Delivers real-time pre-confirmation block data via WebSocket. Specific to the MegaETH chain variant.
Hot Contracts	A ranked list of the most recently and frequently interacted-with smart contracts on the network. Config-gated via NEXT_PUBLIC_HOT_CONTRACTS_ENABLED.
Interchain Indexer	A microservice that indexes cross-chain messages and token transfers across heterogeneous chains (not ZetaChain-specific — a general interoperability indexer). Distinct from CCTX. Backed by NEXT_PUBLIC_CROSS_CHAIN_TXS_ENABLED.
Marketplace	A curated directory of dApps and DeFi applications integrated with Blockscout. Config-gated via NEXT_PUBLIC_MARKETPLACE_ENABLED. Has its own full-page UI with categories and app detail views.
MetaSuites	A third-party browser extension that enhances the Blockscout UI with additional data and links. The frontend notifies it about route changes via a dedicated hook.
MUD Worlds	Instances of the MUD framework — an on-chain autonomous world / game engine. Chains that use MUD expose a list of active worlds. Config-gated via mudFramework feature flag.
Multichain	The feature that aggregates data across multiple Blockscout-indexed chains into a single explorer view. Introduces an "Ecosystems" page and a multichain balance button. Config-gated via NEXT_PUBLIC_MULTICHAIN_ENABLED.
Pools	DEX liquidity pool positions tracked on-chain. Exposed as a "DEX tracker" section under Tokens. Config-gated via NEXT_PUBLIC_DEX_POOLS_ENABLED.
Public Tags	Community-submitted labels for addresses, visible on address pages. Submitted via a dedicated form. Config-gated via NEXT_PUBLIC_METADATA_SERVICE_API_HOST.
Rewards	A token rewards and incentives program operated by Blockscout. Has its own API, context provider, and UI modals. Config-gated via NEXT_PUBLIC_REWARDS_SERVICE_API_HOST.
SolidityScan	A third-party smart contract security vulnerability scanner integrated into contract detail pages. Displays a security score and known vulnerability findings.
SUAVE	A MEV-focused chain developed by Flashbots, built around a trusted execution environment (TEE) architecture. Introduces the Kettle entity.
TAC (Ton Application Chain)	A chain that bridges the TON blockchain and EVM ecosystems. Introduces the Operation entity. Its data comes from a dedicated tac-operation-lifecycle microservice. Config-gated via NEXT_PUBLIC_TAC_OPERATION_LIFECYCLE_API_HOST.
Validators	The set of active block validators on chains that expose this concept (e.g. zkSync Era, Celo). Displayed in a dedicated list. Not present on standard PoW/PoS EVM chains without explicit support. Config-gated via NEXT_PUBLIC_VALIDATORS_CHAIN_TYPE.
Visualize	A service that converts Solidity source code into UML diagrams (class and storage layout). Accessed from contract detail pages. Backed by NEXT_PUBLIC_VISUALIZE_API_HOST.
Watchlist	An Account feature that lets authenticated users track a set of addresses and receive notifications for their activity.