Introduction

This is a mini DeFi trading Bot project on decentralized exchange operating on BSC chain.

Here is the article of why I set this up and steps of how to use it. 👉  Article

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Stack architecture

I use Nest.js framework for Node.js server to connect to BSC chain by using library nestjs-ethers and using aws kms to manage wallet private key. You can use it easily by using the private key of the server directly (but I don’t recommend this way.) Use PostgreSQL for collecting data, and use WardenSwap SDK for getting the token price via WardenSwap router contract for swapping token.

Please note that I’ll not demonstrate the AWS CLI, AWS KMS, PostgreSQL setting up process in this document.

Prerequisites

Please make sure that Node.js > v14.0.0 is installed on your operating system.

Installation

1. Install all dependencies

$ yarn install

2. Create a .env file and use config file from.env.sample

3. Manage wallet private key
   

   • Option 1
     Use AWS KMS (Recommend)
     I use kms (Key Management Service) for encrypting wallet private key and store cipher text base64
     WALLET_ENCRYPT_BASE64 in .env file when the server start, the system uses cipher text base64 to decrypt the private key.
     
     Ref. Managing Encryption Keys With AWS KMS In Node.js

     • Step 1
       Open .env file to set USE_WALLET_TYPE=ENCRYPT_BASE64, AWS_REGION, AWS_KMS_KEY_ID,AWS_CREDENTIAL_PROFILE_NAME, WALLET_PRIVATE_KEY_FOR_ENCRYPTION
       For running script encryption, temporarily put wallet private key in this process.
     • Step 2
       run yarn encryptionPrivateKey script. When encryption is done, search for resultFromScripts/encryptData.txt path folder. Input data with .env file. The key is WALLET_ENCRYPT_BASE64
       
     • Step 3
       Remove key and value WALLET_PRIVATE_KEY_FOR_ENCRYPTION

   • Option2
     Set USE_WALLET_TYPE=PRIVATE_KEY and WALLET_PRIVATE_KEY for instant use.

4. Create PostgreSQL database name defi-trading-bot-manager

Running the app

# development
$ yarn start

# watch mode
$ yarn start:dev

# production mode
$ yarn start:prod

ENV File

Name	Description
USE_WALLET_TYPE	Access wallet with private key or encryption data, You can choose to enter 2 values. ENCRYPT_BASE64 or PRIVATE_KEY
WALLET_PRIVATE_KEY	Private key of wallet
WALLET_ENCRYPT_BASE64	Encryption private key from aws kms
POSTGRES_HOST	PostgreSQL host name
POSTGRES_PORT	PostgreSQL TCP port
POSTGRES_USERNAME	PostgreSQL username
POSTGRES_PASSWORD	PostgreSQL password
POSTGRES_DATABASE	PostgreSQL database name
POSTGRES_AUTO_LOAD_ENTITIES	If true, models will be loaded automatically.
POSTGRES_SYNCHRONIZE	If true, automatically loaded models will be synchronized.
AWS_REGION	AWS Region
AWS_CREDENTIAL_PROFILE_NAME	AWS CLI profile name
AWS_KMS_KEY_ID	AWS KMS key ID for encryption and decryption

REST API

POST /orderbook

Create order trade

Name	Type	In	Description
srcTokenAddress	string	body	Source token address to swap
destTokenAddress	string	body	Destination token address to receive
srcAmount	string	body	Amount of source token to swap
orderType	string	body	Order type you want open, You can choose to enter MARKET, STOP_LIMIT
stopPrice	string	body	The price in a stop order that triggers the creation of a market order

GET /orderbook

List all orderbook

Name	Type	In	Description
orderStatus	string	query	Status of orderbook

GET /orderbook/{orderId}

Get orderbook by order ID

Name	Type	In	Description
orderId	string	path	Get orderbook data from order ID

PATCH /orderbook/{orderId}/cancel

Cancel an active order

Name	Type	In	Description
orderId	string	path	Cancle order form order ID

GET /wardenswap/current-price

Get the current price

Name	Type	In	Description
srcTokenAddress	string	query	Source token address to swap
destTokenAddress	string	query	Destination token address to receive
srcAmount	string	query	Amount of source token to swap

Security Vulnerabilities

If you discover a security vulnerability, please send us an e-mail at [email protected]

Special thanks

• MagicDream, article editor
• Scarlette27, document editor

License

defi-trading-Bot is licensed under the MIT license.

See LICENSE for the full license text.

Developed with ❤️ and 🍺