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Run an LEZ Indexer

Get started with the LEZ Indexer and query finalized LEZ state over HTTP RPC.​

The LEZ Indexer is a service that reads the finalized LEZ state from the Logos Blockchain node and exposes it over an HTTP RPC interface. Any application can use this interface to query blocks, transactions, and account state. This procedure walks you through running an LEZ Indexer locally alongside its dependencies, verifying it is indexing blocks, and querying account state through the RPC.

Before you start, make sure you have the following:

What to expect​

  • You can query finalized LEZ blockchain state including blocks, transactions, and accounts via HTTP RPC on http://localhost:8779.
  • You have a running local stack with the Logos Blockchain node, LEZ Sequencer, and LEZ Indexer coordinated through just commands.
  • You can verify indexer health and confirm it is progressing by calling the getLastFinalizedBlockId and checkHealth RPC methods.

Start the LEZ stack and run the indexer​

The indexer depends on the Logos Blockchain Node and benefits from an LEZ Sequencer running alongside it. For a local deployment, start each service in its own terminal.

  1. In the LEZ repository, run just clean to remove any leftover artifacts from previous runs.

  2. Replace the default value of bedrock_config.addr in lez/indexer/service/configs/debug/indexer_config.json with your Logos Blockchain endpoint and replace the default channel_id there with the LEZ's channel ID. Get the channel ID from the public LEZ sequencer by running:

    curl https://testnet.lez.logos.co/ \
     -H "Content-Type: application/json" \
     -d "{ \
         \"jsonrpc\": \"2.0\", \
         \"method\": \"getChannelId\", \
         \"params\": {}, \
         \"id\": 1 \
     }"

    For a local deployment, run the following commands in two separate terminal windows:

    # Run node, in terminal 1
    just run-bedrock
    # Terminal 2
    just run-sequencer

  3. In a third terminal window, start the LEZ Indexer:

    just run-indexer

    The indexer serves JSON-RPC over HTTP (and WebSocket) on http://localhost:8779 by default. At startup, you will see:

    [2026-06-18T14:21:59Z INFO  indexer_service] Starting Indexer Service RPC server on 0.0.0.0:8779
    [2026-06-18T14:21:59Z INFO  indexer_core] Starting indexer from beginning of channel

    The indexer then listens for block finalizations.

Verify the indexer is progressing​

  1. Call getLastFinalizedBlockId to confirm the indexer is receiving blocks:

    curl -X POST http://localhost:8779 \
      -H "Content-Type: application/json" \
      -d '{"jsonrpc":"2.0","method":"getLastFinalizedBlockId","params":[],"id":1}'

    You will receive a response similar to:

    {"jsonrpc":"2.0","id":1,"result":15}

    The result value should increase each time you repeat the call.

  2. Run the health check to confirm the indexer can reconstruct the full state from the database:

    curl -X POST http://localhost:8779 \
      -H "Content-Type: application/json" \
      -d '{"jsonrpc":"2.0","method":"checkHealth","params":[],"id":1}'

    A healthy indexer returns:

    {"jsonrpc":"2.0","id":1,"result":null}
    info

    checkHealth reconstructs the full LEZ state from the database and can produce heavy disk usage. Run it sparingly.

Query account state using the wallet and RPC​

  1. In a fourth terminal window, query an account state by calling getAccount with the account ID:

    curl -X POST http://localhost:8779 \
      -H "Content-Type: application/json" \
      -d '{"jsonrpc":"2.0","method":"getAccount","params":{"account_id":"2RHZhw9h534Zr3eq2RGhQete2Hh667foECzXPmSkGni2"},"id":1}'

    You will receive a response similar to:

    {"jsonrpc":"2.0","id":1,"result":{"program_owner":"FeYNA4PVvs1SsSuECrmQNnJqtB1jA6CbVBBSVGos7qcu","balance":20000,"data":"","nonce":1}}

  2. Run just run-wallet --help to see all available wallet commands.

Frequently asked questions​

Why is there a delay between sending a transaction and seeing it in the indexer?​

The delay is caused by Logos Blockchain's block finality time. The indexer only processes finalized blocks from the L1 node, so transactions sent through the sequencer are not visible until the corresponding block is finalized. This is expected behavior.

How do I change the indexer configuration?​

The indexer config used by just run-indexer is located at lez/indexer/service/configs/debug/indexer_config.json (a configs/docker/indexer_config.json variant is used for the Docker setup). Two fields control connectivity:

  • bedrock_config — the HTTP address of the Logos Blockchain node.
  • channel_id — the channel that LEZ Sequencer writes into. This must match the sequencer you are using.