Setting up a local simnet

Learn how to run your own local "simnet" node.


Make sure you have the required hardware and dependencies installed. Follow this guide if you haven't already.

Setting up a local simnet

For local development and testing, we can configure a local "simnet", or a fake network on our local computer.

The easiest way to do so is with our melsimnet binary. In the melnode directory:

cargo run --bin melsimnet -- create -s 1. -s 2. -s 3. -s 4.

Running this command will generate several (4 in this case) files and scripts to run the staker nodes in your custom local network. This means that staker 1 will have voting power equivalent to 1 SYM and staker 2 will have 2 SYM, etc.

Let's go through what this all means:

  1. run-staker-*.sh - run an individual staker node

  2. - run all of the staker nodes on a custom local network

  3. staker-*.yaml* - defines the config for an individual staker node (explained below)

  4. genesis.yaml - defines the genesis config for the custom local network (explained below)

After running some (or all) of the nodes, you'll be able to interact with the nodes via melwallet-client, melminter, or even direct HTTP calls.


Should produce logs like:

[2024-05-11T14:28:09Z INFO  melnode] melnode v0.20.7 initializing...
[2024-05-11T14:28:09Z DEBUG melnode::storage::storage] about to sqlite
[2024-05-11T14:28:09Z DEBUG melnode::storage::storage] sqlite initted
[2024-05-11T14:28:09Z DEBUG melnode::storage::storage] about to mesha
[2024-05-11T14:28:09Z DEBUG melnode::args] node storage opened
[2024-05-11T14:28:09Z INFO  melnode] bootstrapping with []
[2024-05-11T14:28:09Z DEBUG melnode::node] starting to listen at
[2024-05-11T14:28:19Z DEBUG melnode::staker] starting consensus for 1...
[2024-05-11T14:28:19Z WARN  melnode::staker] mempool not at the right height, trying again
[2024-05-11T14:28:29Z DEBUG melnode::staker] starting consensus for 1...
[2024-05-11T14:28:29Z DEBUG melstf::state] changing fee multiplier 100 by 1
[2024-05-11T14:28:29Z DEBUG melnode::staker] proposed state has 0 transactions
[2024-05-11T14:28:32Z DEBUG melnode::staker] 1/ DECIDED on a block with 240 bytes within 3.155822014s
[2024-05-11T14:28:32Z DEBUG melstf::state] applied a batch of 0 txx to #<c99d36b369d0fc1bd494b84db635c5964e8359fafff00a1732d19090c3595e41> => #<c99d36b369d0fc1bd494b84db635c5964e8359fafff00a1732d19090c3595e41>
[2024-05-11T14:28:32Z DEBUG melstf::state] changing fee multiplier 100 by 1
[2024-05-11T14:28:32Z DEBUG melnode::storage::storage] applied block 1 / 64e3f33aa793f118ef09fa8aa72a7f6b7b5831dba1f8052d8ac1506e04883a09 in 5.01ms (history insertion 2.42ms)
[2024-05-11T14:28:32Z DEBUG melnode::staker] 1/ COMMITTED the newly decided block within 3.164806678s

melwallet-cli, melminter

To use melwallet or melminter on your local simnet, first set the MELBOOTSTRAP environment variable to a hard-coded block height and header hash to bootstrap clients on this network:

export MELBOOTSTRAP=<network-name>:<block-height>:<header-hash>

You can find all the information needed from the node logs. From the logs above, you can set:

export MELBOOTSTRAP=custom02:1:64e3f33aa793f118ef09fa8aa72a7f6b7b5831dba1f8052d8ac1506e04883a09

To use the wallet, run melwallet-cli with the --bootstrap flag to specify the socket address for connecting to the local node:

melwallet-cli --wallet-path my-wallet.json --bootstrap create --network custom02

Similarly with melminter:

melminter --bootstrap --payout <wallet-address>

Local simnets all support faucet transactions:

melwallet-cli --wallet-path my-wallet.json --bootstrap send-faucet --wait

Custom genesis configuration

This is only needed to start our own custom network, melnode accepts a YAML config file similar to the following:

network: custom02 # anything from custom02..custom08
# specifies the "initial stash" of money in the genesis block
  # what address gets the initial supply of money
  covhash: t5xw3qvzvfezkb748d3zt929zkbt7szgt6jr3zfxxnewj1rtajpjx0
  # how many units (in millionths)
  value: 1000000
  # denomination
  denom: MEL
  # additional data in the UTXO, as a hex string
  additional_data: ""
# specifies all the stakers with consensus power.
# we need to specify ourselves in order to produce any blocks; "Mel-crypttool generate-ed25519" (install via cargo) can generate a keypair for us
    pubkey: 4ce983d241f1d40b0e5b65e0bd1a6877a35acaec5182f110810f1276103c829e
    e_start: 0
    e_post_end: 100000 # essentially never end the stake
    syms_staked: 10000 # does not matter
# Initial fee pool
init_fee_pool: 10000

Custom staker configuration

If we want to run a local custom staker node, melnode accepts a YAML config file:

# secret key; must correspond to "stakes.dead[...]beef.pubkey" in the network config
signing_secret: 5b4c8873cbdb089439d025e9fa817b1df1128231699131c245c0027be880d4d44ce983d241f1d40b0e5b65e0bd1a6877a35acaec5182f110810f1276103c829e
# address for staker-network communication, this can be arbitrary
# must be same as "listen"
# where block rewards are sent
payout_addr: t5xw3qvzvfezkb748d3zt929zkbt7szgt6jr3zfxxnewj1rtajpjx0
# vote for this fee multiplier (higher values charge more fees)
target_fee_multiplier: 10000

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