> For the complete documentation index, see [llms.txt](https://docs.simulacrum.network/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.simulacrum.network/synthetic-blockchain/organization/indexer.md).

# Indexer

Indexers are used to subscribe to updates from [Sources](https://docs.simulacrum.network/synthetic-blockchain/organization/indexer/sources), and use that information to publish the information onchain. Indexers are rewarded for providing valid Commands in the form of points. An indexer is not able to publish a transaction directly, as they must first get [Existential Attestation](https://docs.simulacrum.network/existential-attestation) from an Oracle.