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Getting Started with a Crab Development Node


This guide outlines the steps needed to create a development node for latest features of Darwinia.

A Darwinia development node is your own personal development environment for building and testing applications on Darwinia. For Ethereum developers, it is comparable to Ganache. If you follow to the end of this guide, you will have a Darwinia development node running in your local environment, and will be able to connect it to the default Darwinia Apps GUI.

Getting Started With The Binary

If you know what you are doing, you can directly download the precompiled binaries attached to each release on the Darwinia Release Page. These will not work in all systems. For example, the binaries only work with x86-64 Linux with specific versions of dependencies. The safest way to ensure compatibility is to compile the binary in the system where it will be run from.

First, start by cloning the darwinia-common codebase:

git clone
cd darwinia-common

If you already have Rust installed, you can skip the next two steps. Otherwise, install Rust and its prerequisites via Rust's recommended method by executing:

curl --proto '=https' --tlsv1.2 -sSf | sh

Next, update your PATH environment variable by running:

source $HOME/.cargo/env

Now, build the development node by running:

cargo build --release

If a cargo not found error shows up in the terminal, manually add Rust to your system path or restart your system:

source $HOME/.cargo/env

The initial build will take a while. Depending on your hardware, you should expect approximately 30 minutes for the build process to finish.

Here is what the tail end of the build output should look like:

End of build output

Then, you will want to run the node in dev mode using the following command:

./target/release/drml --dev --tmp

For people not familiar with Substrate, the --dev flag is a way to run a Substrate-based node in a single node developer configuration for testing purposes. You can learn more about --dev in this Substrate tutorial.

You should see an output that looks like the following, showing some blocks has been produced:

Output shows blocks being produced

For more information on some of the flags and options used in the example, check out Common Options. If you want to see a complete list of all of the flags, options, and subcommands, open the help menu by running:

./target/release/drml --help

Connecting To Darwinia Apps

Start by connecting to it with Darwinia Apps Explorer. This will automatically connects to Pangolin TestNet.

Polkadot JS Apps

Click on the top left corner to open the menu to configure the networks, and then navigate down to open the Development sub-menu. In there, you will want to toggle the "Local Node" option, which points to ws:// Next, select the "Save & Reload" button, and the site should connect to your Darwinia development node.

Select Local Node

With Darwinia Apps connected, you will see the the development node has began producing blocks.

Select Local Node

Common Options

Flags do not take an argument. To use a flag, add it to the end of a command. For example:

./target/release/drml --dev --tmp
  • --dev: Specifies the development chain
  • --no-telemetry: Disable connecting to the Substrate telemetry server. For global chains, telemetry is on by default. Telemetry is unavailable if you are running a development (--dev) node.
  • --tmp: Runs a temporary node in which all of the configuration will be deleted at the end of the process
  • --rpc-external: Listen to all RPC interfaces
  • --ws-external: Listen to all Websocket interfaces

For a complete list of flags and options, spin up your Darwinia development node with --help added to the end of the command.

Run Tracing node

Geth's debug and OpenEthereum's trace module provide non-standard RPC methods for getting a deeper insight into transaction processing. Supporting these RPC methods is important because many projects, such as The Graph or Blockscout, rely on them to index blockchain data. To use the supported RPC methods, you need to run a tracing node, which is slightly different than running a full node.

Spinning up a tracing node is similar to running a full node. You will also need to start your node with the following flag(s) depending on the features you would like to enable:

  • --ethapi-debug-targets=debug - optional flag that enables debug_traceTransaction, debug_traceBlockByNumber, and debug_traceBlockByHash.
  • --ethapi-debug-targets=trace - optional flag that enables trace_filter.
  • --wasm-runtime-overrides=overridden-runtimes/<network>/wasms - required flag for tracing that specifies the path where the local WASM runtimes are stored. Depending on the network and the binary version, the overrides runtime file are available at Runtime Overrides Files. Accepts the network as a parameter: pangolin, pangoro now.

Local Development

A simple way to run a tracing node in local is enable evm-tracing feature when compile binary as follows:

$ git clone
$ cd darwinia-common
$ cargo build --release --features evm-tracing

Then, start a tracing node with command:

$ ./target/release/drml --dev --tmp  --ethapi-debug-targets=debug,trace --wasm-runtime-overrides .

Production Environment

$ ./drml \
-d data \
--chain <network> \
--execution wasm \
--ethapi-debug-targets=debug,trace \

Additional flags

By default, the maximum number of trace entries a single request of trace_filter is allowed to return is 500. A request exceeding this limit will return an error. You can set a different maximum limit with the following flag:

  • --ethapi-trace-max-count <uint> — sets the maximum number of trace entries to be returned by the node.

Blocks processed by requests are temporarily stored on cache for a certain amount of time (default is 300 seconds), after which they are deleted. You can set a different time for deletion with the following flag:

  • -ethapi-trace-cache-duration <uint> — sets the duration (in seconds) after which the cache of trace_filter, for a given block, is discarded.

Pre-funded Development Accounts

Your Darwinia development node comes with some pre-funded substrate accounts for development. There are two test accounts are derived from Substrate's canonical development mnemonic:

bottom drive obey lake curtain smoke basket hold race lonely fit walk
  • Alice:

    • Public Address: 2sy7imEZs1Y9GgYrR5Vqkb8EZTmpv2BKr5QNRzB9gkzdAEU2
    • Private Key: 0xe5be9a5092b81bca64be81d212e7f2f9eba183bb7a90954f7b76361f6edb5c0a
  • Bob

    • Public Address: 2rPxSh4RjHYF7g4Lz9Xu1FDGTckwTUmzMFG3Nd3Ucn5PPKJr
    • Private Key: 0x398f0c28f98885e046333d4a41c19cee4c37368a9832c6502f6cfd182e2aef89

Also, included with the development node is a prefunded evm account used for testing purposes:

  • Public Address: 0x6be02d1d3665660d22ff9624b7be0551ee1ac91b
  • Private Key: 0x99b3c12287537e38c90a9219d4cb074a89a16e9cdb20bf85728ebd97c343e342