Subscan

Subscan is a multi-chain block explorer for Polkadot and the wider Substrate ecosystem, launched in 2019 for on-chain researchers, validators, governance participants and development teams. It addresses the fact that Substrate chains store data differently from EVM chains, so general-purpose explorers cannot read staking, referenda or cross-consensus messaging modules, leaving on-chain activity hard for ordinary users to verify.

Mechanically, each connected chain runs its own indexer that parses extrinsics, events and storage items block by block and serves account history, staking rewards, referendum progress, cross-chain messages and asset dashboards. Developers get keyed endpoints with rate limits plus an open-source front-end scaffold, so third parties can deploy a branded explorer; coverage spans close to a hundred parachains and development networks. Its endpoints have long been listed as a Polkadot data source by third-party analytics tools. It is positioned in on-chain explorers and indexing.