Skip to main content
Version: 0.15.0

Juno Sequencer

Juno can now operate as a standalone sequencer. When Juno is run in this experimental mode, users are able to submit transactions to the Juno client, which stores them in a mempool. Every N seconds, Juno will attempt to build a new block using any transactions that are present.

Sequencer mode is activated via a set of dedicated command-line flags:

  • --seq-enable: Enables sequencer mode of operation
  • --seq-block-time: Time interval (in seconds) between block production attempts
  • --seq-genesis-file: Optional path to a genesis file for initializing the state (useful for pre-funded accounts). An example genesis file is provided at ./genesis/genesis_prefund_accounts.json. Users can customize this file to include any accounts, balances, or deployed contracts needed for their setup.
  • --seq-disable-fees: When set, disables transaction fee enforcement in the sequencer (useful for testing)

This makes it ideal for testing rollup flows, simulating block production, or running isolated environments without requiring Layer 1 verification.

Features​

  • Accepts transactions via standard RPC calls
  • Stores transactions in a local mempool
  • Automatically builds blocks at a fixed interval (--seq-block-time)
  • Optionally starts with a blank or pre-funded state

Running the Sequencer​

You can run the Juno sequencer in two modes:

1. Blank State (Clean Genesis)​

./build/juno \
  --http \
  --http-port=6060 \
  --http-host=0.0.0.0 \
  --db-path=./seq-db-tmp \
  --log-level=debug \
  --seq-enable \
  --seq-block-time=1 \
  --network sequencer \
  --disable-l1-verification \
  --rpc-call-max-steps=4123000

2. With Pre-Funded Accounts​

./build/juno \
  --http \
  --http-port=6060 \
  --http-host=0.0.0.0 \
  --db-path=./seq-db-tmp-w-accounts \
  --log-level=debug \
  --seq-enable \
  --seq-block-time=1 \
  --network sequencer \
  --disable-l1-verification \
  --seq-genesis-file ./genesis/genesis_prefund_accounts.json \
  --rpc-call-max-steps=4123000