Leani documentation

Leani is an Ethereum indexing node you run in your own infrastructure. It backfills public history, follows the chain, and stores the results your application needs. Start with one small example:

Run Leani

Install Leani, then follow an Ethereum block or index contract events.

Connect an application

Query and subscribe with TypeScript, then persist changes to PostgreSQL.

Build with the Rust library

Register your own processor, build a custom node, and query its output.

Each tutorial includes a matching configuration, commands, and expected output. The tutorials use a source checkout; Leani is also published as release archives, a Homebrew formula, and the npm SDK (see published releases).

Leani does not maintain EVM state. Arbitrary eth_call, native account balances, and transaction simulation need an execution provider. Read known limitations before connecting a production application.

The expandable sidebar groups hold detailed concepts, API and configuration reference, operations, and contributor material. Start with how Leani works when you want to understand what happens between a source block and your application output.