What is Polkadex? 🚀

Polkadex is a Open Source, Decentralized Exchange Platform made using Substrate Blockchain Framework that provides traders with the centralized user experience.

Why did we do this? 🎁

There are many decentralized exchanges/protocols available in the market for traders but they still prefer to use centralized solutions for their convenience and ease of use knowing very well that their funds are at risk. This is because decentralized solutions are still not user friendly to an average trader. Some of them also have no proper decentralization and also got hacked in the process. We cannot call an exchange decentralized if it can lose or freeze customer funds.

The problems faced by decentralized exchanges are:

• Inadequate UI/UX experience.
• Low liquidity
• Lack of advanced trading features, high-frequency trading, and bots.
• Lack of proper decentralization and interoperability.

To solve the above problems, our goal is to build a fully decentralized, peer-peer, cryptocurrency exchange for the Defi ecosystem in Substrate. The project envisages the creation of a fully decentralized platform for exchanging tokens in a peer-peer, trustless environment, that enables high-frequency trading, high-liquidity, and lightning-fast transaction speed for supporting Defi applications.

In order to address the first problem, we needed to enable features that attract users into the exchange which includes a fast, responsive UI and trading features. It is mainly to attract day traders and retail investors who prefer centralized exchanges due to convenience and speed of execution. The block time of 3s given by the Babe/Grandpa consensus algorithm allows transaction speeds of up to 400/s under test conditions which is more than sufficient to compete with any centralized solutions in the market today. Please check our analysis here. Since Substrate allows the modular implementation of the consensus algorithm, we think a platform like a Substrate will support the future growth of the exchange by changing consensus to accommodate more transactions per second as better ones emerge.

Secondly, the lack of liquidity is addressed by enabling,

1. High-frequency trading using feeless transactions.
2. APIs that enable trading/AMM bots to observe market changes and submit trades.
3. Advanced trading features like stop limit, market limit, Stop loss, Fill/Kill, Post only, TWAP, etc.

Thirdly, proper decentralization and Interoperability are achieved by having a parachain in Polkadot that brings in liquidity from other blockchains and also using ChainBridge protocol that connects directly to the Ethereum network. Hence, traders have two different mechanisms to bring in liquidity.

The value we provide to the Substrate community is,

1. They can build custom UI/UX to connect to our network and create their own custom exchange experience.
2. Traders can contribute their own custom trading algorithms by making use of market data provided by our full nodes.
3. They get a decentralized trading platform to trade Polkadot & Ethereum tokens.
4. This will be one of the first Decentralized exchanges to have High-Frequency Trading bot support using APIs directly from full nodes.

Build the Polkadex Node 💃

To build Polkadex, you will need a proper Substrate development environment. If you need a refresher setting up your Substrate environment, see Substrate's Getting Started Guide.

Note that cloning master might result in an unstable build. If you want a stable version, check out the latest releases.

# Fetch the code
git clone https://github.com/Polkadex-Substrate/Polkadex.git
cd Polkadex

# Build the node (The first build will be long (~30min))
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

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

./target/release/polkadex-node --dev

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.

When running a node via the binary file, data is stored in a local directory typically located in ~/.local/shared/polkadex-node/chains/development/db. If you want to start a fresh instance of the node, you can either delete the content of the folder, or run the following command inside the polkadex folder:

./target/release/node-polkadex purge-chain --dev

This will remove the data folder, note that all chain data is now lost.

Run a local network (two nodes)

• Install subkey, jq

curl https://getsubstrate.io -sSf | bash -s --
brew install jq

• Generate node key using subkey

Alice_Node_Key=$(subkey generate --scheme Ed25519 --output-type Json | jq -r '.secretSeed')

• Run Alice's node

# Purge any chain data from previous runs
./target/release/polkadex-node purge-chain --base-path /tmp/alice --chain local

# Start Alice's node
./target/release/polkadex-node --base-path /tmp/alice \
  --chain local \
  --alice \
  --port 30333 \
  --ws-port 9945 \
  --rpc-port 9933 \
  --node-key $Alice_Node_Key \
  --telemetry-url 'wss://telemetry.polkadot.io/submit/ 0' \
  --validator

2021-06-30 08:12:38 Polkadex Node    
2021-06-30 08:12:38 ✌️  version 3.0.0-6426a73b-x86_64-macos    
2021-06-30 08:12:38 ❤️  by Substrate DevHub <https://github.com/substrate-developer-hub>, 2017-2021    
2021-06-30 08:12:38 📋 Chain specification: Local Testnet    
2021-06-30 08:12:38 🏷 Node name: Alice    
2021-06-30 08:12:38 👤 Role: AUTHORITY    
2021-06-30 08:12:38 💾 Database: RocksDb at /tmp/alice/chains/local_testnet/db    
2021-06-30 08:12:38 ⛓  Native runtime: node-polkadex-265 (node-polkadex-1.tx2.au10)    
2021-06-30 08:12:39 🔨 Initializing Genesis block/state (state: 0xbe0a…5ef3, header-hash: 0xa55f…7888)    
2021-06-30 08:12:39 👴 Loading GRANDPA authority set from genesis on what appears to be first startup.    
2021-06-30 08:12:39 ⏱  Loaded block-time = 3s from genesis on first-launch    
2021-06-30 08:12:39 👶 Creating empty BABE epoch changes on what appears to be first startup.    
2021-06-30 08:12:39 Using default protocol ID "sup" because none is configured in the chain specs    
2021-06-30 08:12:39 🏷 Local node identity is: 12D3KooWEyoppNCUx8Yx66oV9fJnriXwCcXwDDUA2kj6vnc6iDEp    
2021-06-30 08:12:39 📦 Highest known block at #0    
2021-06-30 08:12:39 〽️ Prometheus server started at 127.0.0.1:9615    
2021-06-30 08:12:39 Listening for new connections on 127.0.0.1:9945.    
2021-06-30 08:12:39 👶 Starting BABE Authorship worker    
2021-06-30 08:12:44 💤 Idle (0 peers), best: #0 (0xa55f…7888), finalized #0 (0xa55f…7888), ⬇ 0 ⬆ 0    
2021-06-30 08:12:49 💤 Idle (0 peers), best: #0 (0xa55f…7888), finalized #0 (0xa55f…7888), ⬇ 0 ⬆ 0    
2021-06-30 08:12:54 💤 Idle (0 peers), best: #0 (0xa55f…7888), finalized #0 (0xa55f…7888), ⬇ 0 ⬆ 0

Local node identity is: 12D3KooWEyoppNCUx8Yx66oV9fJnriXwCcXwDDUA2kj6vnc6iDEp shows the Peer ID that Bob will need when booting from Alice's node. This value was determined by the --node-key that was used to start Alice's node.

Now that Alice's node is up and running, Bob can join the network by bootstrapping from her node.

./target/release/polkadex-node purge-chain --base-path /tmp/bob --chain local
./target/release/polkadex-node \
  --base-path /tmp/bob \
  --chain local \
  --bob \
  --port 30334 \
  --ws-port 9946 \
  --rpc-port 9934 \
  --telemetry-url 'wss://telemetry.polkadot.io/submit/ 0' \
  --validator \
  --bootnodes /ip4/127.0.0.1/tcp/30333/p2p/12D3KooWEyoppNCUx8Yx66oV9fJnriXwCcXwDDUA2kj6vnc6iDEp

If all is going well, after a few seconds, the nodes should peer together and start producing blocks. You should see some lines like the following in the console that started Alice node.

2021-06-30 08:16:52 Polkadex Node    
2021-06-30 08:16:52 ✌️  version 3.0.0-6426a73b-x86_64-macos    
2021-06-30 08:16:52 ❤️  by Substrate DevHub <https://github.com/substrate-developer-hub>, 2017-2021    
2021-06-30 08:16:52 📋 Chain specification: Local Testnet    
2021-06-30 08:16:52 🏷 Node name: Bob    
2021-06-30 08:16:52 👤 Role: AUTHORITY    
2021-06-30 08:16:52 💾 Database: RocksDb at /tmp/bob/chains/local_testnet/db    
2021-06-30 08:16:52 ⛓  Native runtime: node-polkadex-265 (node-polkadex-1.tx2.au10)    
2021-06-30 08:16:52 🔨 Initializing Genesis block/state (state: 0xbe0a…5ef3, header-hash: 0xa55f…7888)    
2021-06-30 08:16:52 👴 Loading GRANDPA authority set from genesis on what appears to be first startup.    
2021-06-30 08:16:52 ⏱  Loaded block-time = 3s from genesis on first-launch    
2021-06-30 08:16:52 👶 Creating empty BABE epoch changes on what appears to be first startup.    
2021-06-30 08:16:52 Using default protocol ID "sup" because none is configured in the chain specs    
2021-06-30 08:16:52 🏷 Local node identity is: 12D3KooWRHDuuHg5ZQcJhvVDKud9XkFz2Dcs2GQKF9KKuTD6quq7    
2021-06-30 08:16:53 📦 Highest known block at #0    
2021-06-30 08:16:53 Listening for new connections on 127.0.0.1:9946.    
2021-06-30 08:16:53 👶 Starting BABE Authorship worker    
2021-06-30 08:16:53 🔍 Discovered new external address for our node: /ip4/127.0.0.1/tcp/30334/p2p/12D3KooWRHDuuHg5ZQcJhvVDKud9XkFz2Dcs2GQKF9KKuTD6quq7    
2021-06-30 08:16:53 🔍 Discovered new external address for our node: /ip4/192.168.1.37/tcp/30334/p2p/12D3KooWRHDuuHg5ZQcJhvVDKud9XkFz2Dcs2GQKF9KKuTD6quq7    
2021-06-30 08:16:53 Creating inherent data providers took more time than we had left for the slot.    
2021-06-30 08:16:54 🙌 Starting consensus session on top of parent 0xa55fa19cc37ca1f8d93bc06ca1f6fee767f18200516d9e349938601a3fe97888    
2021-06-30 08:16:54 🎁 Prepared block for proposing at 1 [hash: 0x2959db5e42a7192434d3699d335e5d920da73409963e3081ad43afd93a8cdb4b; parent_hash: 0xa55f…7888; extrinsics (1): [0x4431…4eff]]    
2021-06-30 08:16:54 🔖 Pre-sealed block for proposal at 1. Hash now 0x5263ed1cbf1b4edbc887cc87786471819cd0614d8aeaff3a898c0c3ffda245c2, previously 0x2959db5e42a7192434d3699d335e5d920da73409963e3081ad43afd93a8cdb4b.    
2021-06-30 08:16:54 👶 New epoch 0 launching at block 0x5263…45c2 (block slot 541685138 >= start slot 541685138).    
2021-06-30 08:16:54 👶 Next epoch starts at slot 541685338    
2021-06-30 08:16:54 ✨ Imported #1 (0x5263…45c2)    
2021-06-30 08:16:57 🙌 Starting consensus session on top of parent 0x5263ed1cbf1b4edbc887cc87786471819cd0614d8aeaff3a898c0c3ffda245c2    
2021-06-30 08:16:57 🎁 Prepared block for proposing at 2 [hash: 0x0c513e39a88bcb03d113a18ed824bcbaab03881e9dcdeedbe12e71955dcfe05d; parent_hash: 0x5263…45c2; extrinsics (1): [0xf06a…bf04]]    
2021-06-30 08:16:57 🔖 Pre-sealed block for proposal at 2. Hash now 0x4293ecd46db852f5add54a24acfcd1ea12f6c26d5470b61736d7cf0e039e3e39, previously 0x0c513e39a88bcb03d113a18ed824bcbaab03881e9dcdeedbe12e71955dcfe05d.    
2021-06-30 08:16:57 ✨ Imported #2 (0x4293…3e39)    
2021-06-30 08:16:58 💤 Idle (1 peers), best: #2 (0x4293…3e39), finalized #0 (0xa55f…7888), ⬇ 1.7kiB/s ⬆ 1.9kiB/s 

Using docker

The following commands will setup a local polkadex network made of 2 nodes. It's using the node key (0000000000000000000000000000000000000000000000000000000000000001). But you should generate your own node key using the subkey as the above.

docker build . -t polkadex-node
docker-compose -f 2nodes.yml up --force-recreate

Connecting Polkadot JS Apps to a Local Polkadex Node

The development node is a Substrate-based node, so you can interact with it using standard Substrate tools. The two provided RPC endpoints are:

• HTTP: http://127.0.0.1:9933
• WS: ws://127.0.0.1:9944

Start by connecting to it with Polkadot JS Apps. Open a browser to: https://polkadot.js.org/apps/#/explorer. This will open Polkadot JS Apps, which automatically connects to Polkadot MainNet.

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 Polkadot JS Apps to ws://127.0.0.1:9944. Next, select the Switch button, and the site should connect to your Polkadex development node.

How to run a validator

Here is a guide Run a validator (Polkadex)

Contribute 😍

We would love to work with anyone who can contribute their work and improve this project. The details will be shared soon.

License 📜

Licensed Under GPLv3