Run a local chain

A single-node Yamale network on your machine, with the REST API open so you can point the explorer at it. About two minutes.

You need: Go 1.25.10 or later. Nothing else — protobuf generation and linting run through go tool.

You will end with: a chain producing blocks at localhost:26657, a REST API at localhost:1317, and two funded accounts.

1. Build the node

go build -o blockchaind ./cmd/blockchaind

2. Initialise

./blockchaind init dev --chain-id yamale-devnet-1 --default-denom uyml

This writes ~/.blockchain. Every command below takes --home if you would rather keep it somewhere else.

3. Create and fund two accounts

./blockchaind keys add alice --keyring-backend test
./blockchaind keys add bob --keyring-backend test

./blockchaind genesis add-genesis-account $(./blockchaind keys show alice -a --keyring-backend test) 200000000000uyml --keyring-backend test
./blockchaind genesis add-genesis-account $(./blockchaind keys show bob -a --keyring-backend test) 100000000000uyml --keyring-backend test

Amounts are in uyml, the base unit: 200000000000uyml is 200,000 YML.

The test keyring stores keys unencrypted on disk. That is fine for a throwaway local chain and wrong for anything else — a real validator uses --keyring-backend file.

4. Make alice a validator

./blockchaind genesis gentx alice 100000000000uyml --chain-id yamale-devnet-1 --keyring-backend test
./blockchaind genesis collect-gentxs
./blockchaind genesis validate-genesis

The last command should print that the genesis file is valid.

Validators normally need a governance vote to join this chain, but the gate does not apply at genesis — that is what makes the founding ceremony possible. See x/validatorgov.

5. Open the API

Two settings in ~/.blockchain/config/app.toml:

minimum-gas-prices = "0uyml"

[api]
enable = true

Write these files without a byte-order mark. The TOML parser rejects a BOM with invalid character at start of key, and several editors add one silently when saving as UTF-8.

Without minimum-gas-prices the node refuses to start at all, with set min gas price in app.toml or flag or env variable.

6. Start

./blockchaind start

Blocks begin immediately. Check it:

curl -s localhost:26657/status | grep -o '"latest_block_height":"[0-9]*"'
curl -s localhost:1317/cosmos/bank/v1beta1/supply

7. Send something

./blockchaind tx bank send \
  $(./blockchaind keys show alice -a --keyring-backend test) \
  $(./blockchaind keys show bob -a --keyring-backend test) \
  12500000uyml \
  --chain-id yamale-devnet-1 --keyring-backend test --fees 500uyml --yes

That is 12.5 YML. The command prints a txhash; the code in that output only means the node accepted it for inclusion. To see whether it actually succeeded:

./blockchaind query tx <txhash>

code: 0 there is the real success.

8. Point the explorer at it

cd clients && npm install && npm run dev

Open http://localhost:5173. The dev server proxies the node, so nothing needs CORS opened up.

Things worth knowing

Block time. The default is five seconds. One-second blocks are tempting for development, but a chain left running at that rate writes its consensus WAL hard enough to exhaust file resources on some machines — which shows up as a CONSENSUS FAILURE in the log and a node that keeps producing blocks while quietly including no transactions. If transactions stop landing, check the log before suspecting your transaction.

Supply grows fast. The default emission schedule is tuned so its decay curve is visible within a short run rather than over years. On a devnet that means total supply climbs from the genesis allocation into the hundreds of millions of YML within an hour. That is the schedule doing what it says; it is not what a long-lived testnet should launch with. See x/emission.

Resetting. ./blockchaind comet unsafe-reset-all clears the chain data but keeps your keys and genesis, which is usually what you want when experimenting.