Qubic Hackathon Documentation

Table of Contents

• Overview
• Quick Start
• What is Qubic?
• Hackathon Process
  • Development Process Overview
  • Team Participation
  • Smart Contract Development & Deployment Process
  • SSH Connection Instructions
• Development Resources
  • Smart Contract Development
  • Best Practices
  • Online Development Tools
  • Qubic CLI Commands Reference
• Technical Infrastructure
  • RPC Endpoints
  • Faucet
  • Available Testnet Seeds
  • TypeScript Library
  • Smart Contract Examples
• Frontend Application
  • Frontend Overview
  • Frontend Features
  • Connecting to a Node
  • Smart Contract Interaction Examples
• Testing Smart Contracts
  • CLI Testing
  • RPC Testing
  • Event Decoding
• Project Structure
• FAQs
• Contact

Overview

Welcome to the Qubic Hackathon repository! This repository serves as the central hub for participants to submit their smart contracts, access resources, and interact with the infrastructure team during Qubic hackathons. Whether you're participating in your first Qubic hackathon or you're a returning developer, this documentation will guide you through the entire process of building innovative smart contracts on the Qubic.

Quick Start

1. Join the Qubic Discord Community: discord.gg/qubic

2. Get Access to a Test Node:

   • The process for accessing testnet nodes is being updated for future hackathons. Please check with the hackathon organizers for the current access procedure.
   • Deploy the Random template smart contract using the provided scripts

3. Customize Your Smart Contract:

   • Fork the Qubic Core repository and switch to the testnets/release-253 branch
   • Modify the src/contracts/random.h template file with your own business logic
   • Keep the existing function structure but add your own state variables and procedures
   • Use the provided deployment script to deploy your modified contract

4. Explore the Example dApp:

   • Check out https://github.com/icyblob/hm25-frontend - a complete example dApp
   • Features full wallet integrations (MetaMask Snap, WalletConnect, seed phrase, Vault file)
   • Demonstrates real-world smart contract interactions with the Random template
   • Use this as a reference implementation for your own Qubic dApps

5. Connect to Your Node:

   • The app connects to a testnet node by default
   • To connect to your own node, use the ConnectLink feature in the top right
   • Use format: http://<your-node-ip> (no port needed)

6. Interact with Your Smart Contract:

   • Use the frontend to call your SC functions
   • View contract statistics
   • Use provided test seeds to sign transactions

What is Qubic?

Qubic is a blockchain platform that enables the creation and execution of smart contracts. Qubic smart contracts are self-executing programs that run within the Qubic ecosystem, automating logic, managing balances, and interacting with the blockchain to process transactions securely and efficiently.

Key Features of Qubic Smart Contracts

• Each smart contract has its own balance – funds sent to the SC are tracked internally
• Transactions interact with the SC – functions in the SC execute based on received inputs
• Epoch-based execution – Qubic SCs operate in epoch cycles (BEGIN_EPOCH and END_EPOCH events)
• State persistence – Qubic SCs use state storage to persist data across transactions

Hackathon Process

Development Process Overview

The Qubic ecosystem is complex to set up from scratch. To simplify development for this hackathon, we're providing:

1. A dedicated test node accessible via SSH
2. A deployment script that sets up the entire Qubic ecosystem in one machine with a single command
3. A pre-approved smart contract template (HM25.h) that you can modify

This approach means you can focus on writing your smart contract code without worrying about the complex infrastructure required to run the Qubic network.

Team Participation

• Each team will develop their own smart contract
• The team will support deployment and testing

Smart Contract Development & Deployment Process

1. Teams develop their smart contracts using C++

2. Fork the Qubic core repository from https://github.com/qubic/core

3. Switch to the testnets/release-253 branch which contains the optimized test node version

4. Develop your smart contract by editing the random.h template file

   • This is the template smart contract we've prepared for the hackathon
   • You can modify this file with your SC code
   • Note: On Qubic mainnet, each SC needs to be IPOed and approved by computors, but for this hackathon, we've simplified the process with a pre-approved template contract

5. Advanced developers can also add functions in files under contract_core and contracts folders, but this is not recommended for beginners

6. To test your smart contract on a dedicated test node:

   • Contact the hackathon organizers to get access to your dedicated testnet node (the specific process may vary by hackathon)
   • Connect to the test node via SSH (Visual Studio Code's SSH extension is recommended so you can see and modify files directly)
   • Run the deployment script:

     ./deploy.sh https://github.com/{your-username}/core/tree/testnets/release-253

     in the /root/qubic/qubic-docker folder
   • The script will start the node, send indices to get the network ticking, and deploy RPC
   • Note: Your repository must be public, not private, for this to work

7. If deployment is successful, you'll see:

   Deployment completed successfully.
   RPC is available at: http://185.84.224.158/tick-info
   To connect to the testnet via qubic-cli, use:
   _______________________
   |                     |
   | IP: 185.84.224.158  |
   | Port: 31841         |
   |_____________________|
   Example commands:
   ./qubic-cli -nodeip 185.84.224.158 -nodeport 31841 -getcurrenttick
   Response:
   Tick: 21190235
   Epoch: 152
   Number Of Aligned Votes: 0
   Number Of Misaligned Votes: 0
   Initial tick: 21190000
   ./qubic-cli -nodeip 185.84.224.158 -nodeport 31841 -getbalance WEVWZOHASCHODGRVRFKZCGUDGHEDWCAZIZXWBUHZEAMNVHKZPOIZKUEHNQSJ
   Response:
   Identity: WEVWZOHASCHODGRVRFKZCGUDGHEDWCAZIZXWBUHZEAMNVHKZPOIZKUEHNQSJ
   Balance: 1000000000
   Incoming Amount: 1000000000
   Outgoing Amount: 0
   Number Of Incoming Transfers: 1
   Number Of Outgoing Transfers: 0
   Latest Incoming Transfer Tick: 15502487
   Latest Outgoing Transfer Tick: 0
   Tick: 21190235
   Spectum Digest: c747adefec62c38dd4a64d554f72723daf71aded23ea5782625ff3cf16e49ec2
   =======================================================================================================================
   

8. If deployment fails, review the logs to identify and fix issues with your smart contract

9. After successful deployment, test your smart contract using the Qubic CLI

   • You can use the online CLI at qubicdev.com or run the CLI locally
   • For Mac OS Silicon chips, use the branch specified in the CLI section of this README

10. Build a frontend application that interacts with your smart contract through the testnet node's RPC

11. When you've completed your smart contract and application, notify us on the #dev channel on Discord for feedback and review

Important: Each team's testnet node will have its own IP address and RPC endpoint. This allows you to call directly to your specific node. We've set up the testnet nodes to make the process simpler so teams can focus on building rather than dealing with the complexities of running a Qubic node.

Critical: Every time you modify your smart contract, you MUST first run the cleanup command ./cleanup.sh and then redeploy using ./deploy.sh. If you don't do this, the node will continue running with your old code changes.

SSH Connection Instructions

To access your dedicated testnet node for smart contract development:

1. Request access credentials

   • Contact the hackathon organizers to get access to your dedicated testnet node (the specific process may vary by hackathon)
   • You will be provided with:
     • IP address: (specific to your assigned node)
     • Username: typically root
     • Password: Will be provided securely by the organizers

2. Connect via SSH We recommend using Visual Studio Code with the SSH extension for the best experience:

   a. Install the "Remote - SSH" extension in VS Code

   b. Click on the green icon in the bottom-left corner

   c. Select "Connect to Host..." and add a new SSH host:

   ssh root@YOUR_NODE_IP
   

   d. Enter the password when prompted

   e. Browse to the /root/qubic/qubic-docker directory to find the deployment scripts

3. Deploy your forked repository Run the deployment script with your GitHub repository URL:

   ./deploy.sh https://github.com/{your-username}/core/tree/testnets/release-253

   Note: Ensure your repository is public, as private repositories will not work with this script.

4. Monitor deployment

   • Successful deployment will display RPC endpoint information
   • Failed deployments will show error logs to help you troubleshoot

5. Monitor transaction logs After successful deployment, you can monitor real-time transaction logs using the qlogging service:

   ./qubic/scripts/qlogging 127.0.0.1 31841 1 2 3 4 21180000

   Run this command in a separate terminal tab to see real-time logs of transactions, transfers, and other events happening on your node. The output will look like:

   EventTx #1FromId Told1 2[1] 21183461.153 QU transfer: from WTUBWAEQJHTFIEDXCJHVRXAXYBFCHAPQUPOQMGTJVGXYEBVRYTOVFHLFBCMB to MAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAWWD 10000QU.
   Tick 21183462 doesn't generate any log
   Tick 21183463 doesn't generate any log
   ...
   [4] 21183473.153 Burn: MAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAWLWD burned 100000 QU
   

   This is invaluable for debugging and understanding how your smart contract interacts with the network.

6. Shutdown procedure When you're done working, clean up your deployment:

   ./cleanup.sh

Development Resources

Smart Contract Development

Qubic smart contracts are written in C++ with specific structures and patterns. Below is an example based on our template:

using namespace QPI;

struct hm25
{
};

struct Random : public ContractBase
{
public:
    struct Echo_input{};
    struct Echo_output{};

    struct Burn_input{};
    struct Burn_output{};

    struct GetStats_input {};
    struct GetStats_output
    {
        uint64 numberOfEchoCalls;
        uint64 numberOfBurnCalls;
    };

private:
    uint64 numberOfEchoCalls;
    uint64 numberOfBurnCalls;

    /**
    Send back the invocation amount
    */
    PUBLIC_PROCEDURE(Echo)
        state.numberOfEchoCalls++;
        if (qpi.invocationReward() > 0)
        {
            qpi.transfer(qpi.invocator(), qpi.invocationReward());
        }
    _

    /**
    * Burn all invocation amount
    */
    PUBLIC_PROCEDURE(Burn)
        state.numberOfBurnCalls++;
        if (qpi.invocationReward() > 0)
        {
            qpi.burn(qpi.invocationReward());
        }
    _

    PUBLIC_FUNCTION(GetStats)
        output.numberOfBurnCalls = state.numberOfBurnCalls;
        output.numberOfEchoCalls = state.numberOfEchoCalls;
    _

    REGISTER_USER_FUNCTIONS_AND_PROCEDURES

        REGISTER_USER_PROCEDURE(Echo, 1);
        REGISTER_USER_PROCEDURE(Burn, 2);

        REGISTER_USER_FUNCTION(GetStats, 1);
    _

    INITIALIZE
        state.numberOfEchoCalls = 0;
        state.numberOfBurnCalls = 0;
    _
};

This template demonstrates:

• Input/output structures for functions
• Procedures that can modify state
• State tracking (counters for function calls)
• Function registration
• State initialization

Best Practices for Qubic Smart Contracts

1. Smart Contract Initialization

   • Always initialize all state variables explicitly

2. Managing Smart Contract Balances

   • Fetch SC balance dynamically using qpi.getEntity()
   • Never assume a fixed amount—always track incoming and outgoing funds

3. Handling Transactions Correctly

   • Ensure transactions are properly validated before modifying state

4. Using State Variables Correctly

   • Store all necessary data in state—Qubic SCs do not retain local variables between calls

5. Security Best Practices

   • Use require() conditions before modifying state
   • Validate input values
   • Use proper balance fetching methods

Online Development Tools

Integration Tutorial Videos

The Qubic integration team that runs the RPC has created a comprehensive video series that walks through all the essential integration operations step by step. These videos provide official, hands-on guidance for implementing Qubic integrations using Go.

YouTube Playlist: Qubic Integration Tutorial Series

Code Examples: All video tutorials have corresponding code examples in the qubic-integration-examples directory.

The series covers:

1. Get Balance Part 1 & 2 - Learn how to retrieve account balances from the Qubic network
   • 📁 Code Example
2. Check Transactions - Understand how to query and verify transaction information
   • 📁 Code Example
3. Query Smart Contract - Discover how to interact with and query smart contracts
   • 📁 Code Example
4. Send Transaction - Master the process of creating and broadcasting transactions
   • 📁 Code Example

Each video corresponds to the practical examples found in the qubic-integration-examples directory, which contains complete Go code implementations for each integration scenario. These tutorials are invaluable for developers who want to understand the complete flow of integrating with the Qubic network, straight from the team that maintains the RPC infrastructure.

Note: While these examples use Go, the concepts and API interactions demonstrated are applicable to any programming language when building Qubic integrations.

Smart Contract Examples

For smart contract examples, you can explore the official Qubic smart contracts:

• Official Qubic Smart Contracts
• Contract Core Functions
• Platform Functions

Since our core smart contract library is still in development, you can utilize functions from both the contract core and platform libraries. If you encounter a missing function, feel free to add it to the appropriate core or platform files. For any questions, post them on the dev channel for guidance.

Some notable examples include:

• Asset management contracts
• Staking contracts
• Multi-signature wallets
• Trading mechanisms

For interacting with deployed contracts, use the local Qubic CLI by following the instructions on the Qubic CLI GitHub. The CLI works with all systems and these commands are used to call and test smart contracts.

Qubic CLI Commands Reference

Installation and Setup

Install the Qubic CLI from the Qubic CLI repository. The CLI works with all systems.

Essential CLI Commands

Here are some essential CLI commands you can use:

• ./qubic-cli -help: Prints the help message with all available commands
• ./qubic-cli -nodeip <IPv4_ADDRESS>: Specifies the IP address of the target node
• ./qubic-cli -nodeport <PORT>: Specifies the port of the target node
• ./qubic-cli -getbalance <IDENTITY>: Retrieves the balance of a specified identity
• ./qubic-cli -sendtoaddress <TARGET_IDENTITY> <AMOUNT>: Sends Qubic to a target identity
• ./qubic-cli -gettxinfo <TX_ID>: Gets transaction information
• ./qubic-cli -getcurrenttick: Fetches the current tick information of the node

For a complete list of commands, visit the Qubic CLI Readme.

Technical Infrastructure

RPC Endpoints

Qubic provides RPC (Remote Procedure Call) endpoints for interacting with the blockchain:

• Mainnet RPC: https://rpc.qubic.org
• Public Testnet RPC: https://testnet-rpc.qubicdev.com (Anyone can use this for testing)
• Testnet Node IP: (example: http://66.248.204.226/v1/tick-info)

These endpoints can be used with the Qubic TypeScript library or direct API calls to communicate with the Qubic network.

Quick Testing with Public Testnet

If you want to quickly test general Qubic interactions without setting up your own node, you can use the public testnet RPC at https://testnet-rpc.qubicdev.com. This is perfect for:

• Learning Qubic RPC interactions
• General blockchain interaction testing
• Understanding Qubic network functionality

Note: This public testnet is for general Qubic interaction only. To test your own custom smart contracts, you need your own dedicated test node.

Available RPC Services and documentation:

• Qubic Live Tree - For real-time data access

Available RPC Services

The Qubic RPC API offers a variety of endpoints for different use cases, as detailed in the official documentation and Swagger archive. Key endpoints include:

1. General Network Information

   • GET /v1/status: Retrieves the latest RPC server statistics, including:
     • timestamp: Current timestamp (e.g., "1724325433")
     • circulatingSupply: Total QUs in circulation (e.g., "109929085175710")
     • activeAddresses: Number of active addresses (e.g., 477228)
     • price: Current QU price in USD (e.g., 0.000001743)
     • marketCap: Market capitalization in USD (e.g., "191606393")
   • GET /v1/tick: Returns the current tick (block height) of the network.

2. Transaction Handling

   • POST /v1/broadcast-transaction: Broadcasts a transaction to the network.
   • GET /v1/tick-transactions/{tick}: Retrieves a list of approved transactions for a given tick.
   • GET /v1/transaction/{txId}: Fetches details of a specific transaction.
   • GET /v1/transaction-status/{txId}: Checks the status of a specific transaction.

3. Account and Balance Queries

   • GET /v1/balances/{addressId}: Retrieves the balance for a specified address ID.
   • GET /v1/transfers/{identity}/{fromTick}/{toTick}: Lists transfer transactions for an identity within a tick range.

4. Advanced Blockchain Data

   • GET /v1/tick-info/{tick}: Provides tick information, including timestamp, epoch, and included transaction IDs.
   • GET /v1/chain-hash/{tick}: Returns the chain hash for a specific tick.
   • GET /v1/quorum-tick/{tick}: Retrieves quorum tick data for a specific tick.
   • GET /v1/store-hash/{tick}: Gets the store hash for a specific tick.

Using RPC Endpoints

These endpoints can be accessed via HTTP requests (e.g., using curl, a TypeScript library, or any HTTP client). Example using curl:

curl https://rpc.qubic.org/v1/status

You can build applications that interact with Qubic using these RPC endpoints, without the need to run your own node.

For detailed specifications and response formats, refer to the Qubic RPC Swagger Documentation.

Smart Contract Interaction Limitations

Important: The RPC endpoints have varying levels of support for smart contract interactions:

• Pre-deployed HM25 Template: The example frontend application demonstrates how to interact with the pre-deployed HM25 template contract using RPC endpoints like /v1/querySmartContract for reading data and /v1/broadcast-transaction for executing procedures.

• Your Custom Contracts: When you modify and deploy your own version of the smart contract, initially you may need to use the Qubic CLI to test your custom functions. After verifying your contract is working correctly, you can integrate it with the frontend following the patterns shown in the example application.

• RPC vs CLI Usage: For most teams, the example frontend application provides all necessary components to interact with your smart contract through RPC. The CLI is most useful for debugging and initial testing.

For further integration details, explore the Qubic Integration GitHub.

Faucet

Need test funds for general Qubic interaction and development? Get testnet Qubics from the online faucet:

Visit https://qforge.qubicdev.com/ to get testnet funds instantly. These funds work with the public testnet RPC at https://testnet-rpc.qubicdev.com for general Qubic interactions and testing.

Note: This is for general Qubic interaction, not for testing your own smart contracts. To test your own smart contracts, you need access to your own dedicated test node (see the hackathon setup process above).

Available Testnet Seeds

The testnet node comes with pre-funded seeds that you can use for testing. Each seed contains 1 billion Qubic tokens. Here's the list of available seeds:

fwqatwliqyszxivzgtyyfllymopjimkyoreolgyflsnfpcytkhagqii
xpsxzzfqvaohzzwlbofvqkqeemzhnrscpeeokoumekfodtgzmwghtqm
ukzbkszgzpipmxrrqcxcppumxoxzerrvbjgthinzodrlyblkedutmsy
wgfqazfmgucrluchpuivdkguaijrowcnuclfsjrthfezqapnjelkgll
kewgvatawujuzikurbhwkrisjiubfxgfqkrvcqvfvgfgajphbvhlaos
nkhvicelolicthrcupurhzyftctcextifzkoyvcwgxnjsjdsfrtbrbl
otyqpudtgogpornpqbjfzkohralgffaajabxzhneoormvnstheuoyay
ttcrkhjulvxroglycvlpgesnxpwgjgvafpezwdezworzwcfobevoacx
mvssxxbnmincnnjhtrlbdffulimsbmzluzrtbjqcbvaqkeesjzevllk
jjhikmkgwhyflqdszdxpcjrilnoxerfeyttbbjahapatglpqgctnkue
nztizdwotovhuzchctpfdgylzmsdfxlvdcpikhmptqjbwwgbxavhtwo
lxbjeczdoqyjtzhizbeapkbpvfdbgxxbdbhyfvzhbkysmgdxuzspmwu
zwoggmzfbdhuxrikdhqrmcxaqmpmdblgsdjzlesfnyogxquwzutracm
inkzmjoxytbhmvuuailtfarjgooearejunwlzsnvczcamsvjlrobsof
htvhtfjxzqandmcshkfifmrsrikrcpsxmnemcjthtmyvsqqcvwckwfk
hmsmhamftvncxcdvxytqgdihxfncarwzatpjuoecjqhceoepysozwlp
wrnohgpgfuudvhtwnuyleimplivlxcaswuwqezusyjddgkdigtueswb
fisfusaykkovsskpgvsaclcjjyfstrstgpebxvsqeikhneqaxvqcwsf
jftgpcowwnmommeplhbvgotjxrtkmiddcjmitbxoekwunmlpmdakjzq
svaluwylhjejvyjvgmqsqjcufulhusbkkujwrwfgdphdmesqjirsoep
lzinqhyvomjzqoyluifguhytcgpftdxndswbcqriecatcmfidbnmvka
mqamjotnshocvekufdqylgtdcembtddlfockjyaotfdvzqpvkylsjjk
asueorfnexvnthcuicsqqppekcdrwizxqlnkzdkazsymrotjtmdnofe
ahfulnoaeuoiurixbjygqxiaklmiwhysazqylyqhitjsgezhqwnpgql
omyxajeenkikjvihmysvkbftzqrtsjfstlmycfwqjyaihtldnetvkrw
zrfpagcpqfkwjimnrehibkctvwsyzocuikgpedchcyaotcamzaxpivq
kexrupgtmbmwwzlcpqccemtgvolpzqezybmgaedaganynsnjijfyvcn

You can use these seeds with the Qubic CLI to interact with your deployed smart contracts. For example:

./qubic-cli -nodeip YOUR_NODE_IP -nodeport YOUR_NODE_PORT -seed fwqatwliqyszxivzgtyyfllymopjimkyoreolgyflsnfpcytkhagqii -somecommand

TypeScript Library

Qubic provides an official TypeScript library to interact with the Qubic network programmatically:

• Qubic TypeScript Library
• Examples

Installation

yarn add @qubic-lib/qubic-ts-library

or

npm install @qubic-lib/qubic-ts-library

Basic Usage

// Import helper
import { QubicHelper } from 'qubic-ts-library/dist/qubicHelper'

// Create an ID Package with private/public key and human readable address
const id = await helper.createIdPackage("your-seed-phrase");

// Connect to a node
import { QubicConnector } from 'qubic-ts-library/dist/qubicConnector'
const connector = new QubicConnector("https://rpc.qubic.org");

// Get balance
const balance = await connector.getBalance("IDENTITY_HERE");

Check the examples directory for more usage scenarios, including:

• Creating transactions
• Fetching balances
• Managing multiple users
• Handling deposits/withdrawals

Frontend Application

Frontend Overview

We've built a frontend application that demonstrates how to interact with the Qubic blockchain and specifically with the HM25 template smart contract deployed on the testnet. This application serves as an example of how to build user interfaces for Qubic-based dApps.

Source Code: https://github.com/icyblob/hm25-frontend - Clone this repository to run the app locally, detailed setup instructions are provided in the repository README.

Frontend Features

• Connect to a Qubic node through its RPC endpoint
• Integrated wallet support:
  • MetaMask Snap integration
  • WalletConnect support
  • Seed phrase login
  • Vault file authentication
• Interact with the HM25 template smart contract
  • Call Echo function (returns funds to the sender)
  • Call Burn function (burns funds permanently)
  • View contract statistics

Connecting to a Node

By default, the app connects to a testnet node at http://91.210.226.146.

Important Notes:

1. The frontend app connects to a shared testnet node by default
2. Each team will be assigned their own dedicated node (accessible via SSH) where they'll deploy their custom contract
3. After running the deploy.sh script on your assigned node, you'll need to connect the frontend to your node
4. The RPC endpoint format has changed: Previously it was http://<HOST_IP>:8000, but now it's simply http://<HOST_IP> without the port

You can connect to your dedicated node:

1. Open the app in your browser
2. Click on the ConnectLink at the top right
3. Select "Connect to Server"
4. Enter your node URL (e.g., http://your-node-ip) without any port
5. Refresh the page

How Transactions Work: The wallet is only used for signing transactions. After a transaction is signed, it will be broadcast to the network that the dapp is connecting to, as determined by the HTTP endpoint in the configuration.

The app interacts with the HM25 template smart contract that provides Echo, Burn, and GetStats functionality.

Smart Contract Interaction Examples

The frontend interacts with the HM25 smart contract through several key functions defined in src/components/api/HM25Api.jsx. Here's how it works:

1. Contract Constants

First, we define constants for interacting with the contract:

export const HM25_CONTRACT_INDEX = 12  // The index of the HM25 contract on the testnet

// Function and procedure types
export const PROC_ECHO = 1     // Echo procedure type ID
export const PROC_BURN = 2     // Burn procedure type ID
export const FUNC_GET_STATS = 1  // GetStats function type ID

2. Reading Contract State (GetStats)

To read data from the smart contract (like statistics), we use the /v1/querySmartContract endpoint:

export async function fetchHM25Stats(httpEndpoint) {
    // Create the query data for the GetStats function (type 1)
    const queryData = makeJsonData(HM25_CONTRACT_INDEX, FUNC_GET_STATS, 0, '')
    
    try {
        // Make HTTP POST request to the node's RPC endpoint
        const response = await fetch(`${httpEndpoint}/v1/querySmartContract`, {
            method: 'POST',
            headers: HEADERS,
            body: JSON.stringify(queryData),
        })
        
        if (!response.ok) {
            throw new Error(`HTTP error! status: ${response.status}`)
        }
        
        const json = await response.json()
        // Decode the response data from base64
        const raw = base64.decode(json.responseData)
        const buf = Buffer.from(raw, 'binary')
        
        // Parse the 16-byte response (2 uint64 values)
        return {
            numberOfEchoCalls: buf.readBigUInt64LE(0),  // First 8 bytes
            numberOfBurnCalls: buf.readBigUInt64LE(8),  // Second 8 bytes
        }
    } catch (error) {
        console.error('Error fetching HM25 stats:', error)
        return {
            numberOfEchoCalls: 0n,
            numberOfBurnCalls: 0n,
        }
    }
}

3. Creating Transaction for Echo Procedure

To call the Echo procedure (which returns funds to the sender), we build a transaction:

export async function buildEchoTx(qHelper, sourcePublicKey, tick, amount) {
    const finalTick = tick + TICK_OFFSET  // Add offset to current tick
    const INPUT_SIZE = 0  // No input data for Echo
    const TX_SIZE = qHelper.TRANSACTION_SIZE + INPUT_SIZE
    const tx = new Uint8Array(TX_SIZE).fill(0)
    const dv = new DataView(tx.buffer)

    // Build the transaction
    let offset = 0
    // Source address
    tx.set(sourcePublicKey, offset)
    offset += qHelper.PUBLIC_KEY_LENGTH
    // Target contract (HM25)
    tx[offset] = HM25_CONTRACT_INDEX
    offset += qHelper.PUBLIC_KEY_LENGTH
    // Amount to send
    dv.setBigInt64(offset, BigInt(amount), true)
    offset += 8
    // Tick for the transaction
    dv.setUint32(offset, finalTick, true)
    offset += 4
    // Procedure type (Echo = 1)
    dv.setUint16(offset, PROC_ECHO, true)
    offset += 2
    // Input size
    dv.setUint16(offset, INPUT_SIZE, true)

    return tx
}

4. Creating Transaction for Burn Procedure

Similarly, to call the Burn procedure (which permanently burns funds):

export async function buildBurnTx(qHelper, sourcePublicKey, tick, amount) {
    const finalTick = tick + TICK_OFFSET
    const INPUT_SIZE = 0
    const TX_SIZE = qHelper.TRANSACTION_SIZE + INPUT_SIZE
    const tx = new Uint8Array(TX_SIZE).fill(0)
    const dv = new DataView(tx.buffer)

    // Build the transaction (similar structure to Echo but different procedure type)
    let offset = 0
    tx.set(sourcePublicKey, offset)
    offset += qHelper.PUBLIC_KEY_LENGTH
    tx[offset] = HM25_CONTRACT_INDEX
    offset += qHelper.PUBLIC_KEY_LENGTH
    dv.setBigInt64(offset, BigInt(amount), true)
    offset += 8
    dv.setUint32(offset, finalTick, true)
    offset += 4
    // Use PROC_BURN (2) instead of PROC_ECHO
    dv.setUint16(offset, PROC_BURN, true)
    offset += 2
    dv.setUint16(offset, INPUT_SIZE, true)

    return tx
}

5. Complete Flow for Executing a Transaction

When a user interacts with the HM25 contract through the UI:

1. The frontend fetches the current tick from the node
2. It builds a transaction using buildEchoTx or buildBurnTx
3. The transaction is signed by the wallet
4. The signed transaction is broadcast to the node via the /v1/broadcast-transaction endpoint
5. The app shows the user the transaction status

This approach separates:

• The wallet (responsible only for signing transactions)
• The node connection (determined by the HTTP endpoint setting)
• The business logic (in the smart contract)

The frontend simply orchestrates these components to provide a seamless user experience.

Testing Smart Contracts

There are two primary ways to test your smart contracts on Qubic: using the CLI or using RPC endpoints. Each method has its own advantages and use cases.

CLI Testing

The Qubic CLI provides a direct way to interact with your deployed smart contracts. This is often the easiest method for initial testing and debugging. For complete CLI command reference, see the Qubic CLI Commands Reference section above.

Advantages of CLI Testing

• Direct communication with the node
• Easier for debugging initial contract functionality
• No need to handle encoding/decoding manually
• Comprehensive error messages

RPC Testing

RPC (Remote Procedure Call) testing involves making HTTP requests to your node's RPC endpoint. This method is more suitable for frontend applications and automated testing.

Key RPC Endpoints for Smart Contract Testing

• POST /v1/querySmartContract - For reading contract state (functions)
• POST /v1/broadcast-transaction - For executing contract procedures
• GET /v1/tick-info - For getting current tick information

Base64 Encoding/Decoding

When using RPC endpoints, you need to handle Base64 encoding and decoding:

For Input Data: Encode your input parameters in Base64 before sending to the contract For Output Data: Decode the Base64 response from the contract to extract readable data

Example of decoding response data:

const response = await fetch(`${httpEndpoint}/v1/querySmartContract`, {
    method: 'POST',
    headers: HEADERS,
    body: JSON.stringify(queryData),
})

const json = await response.json()
// Decode the response data from base64
const raw = base64.decode(json.responseData)
const buf = Buffer.from(raw, 'binary')

// Parse the decoded data according to your contract's output structure
const result = {
    field1: buf.readBigUInt64LE(0),  // First 8 bytes
    field2: buf.readBigUInt64LE(8),  // Second 8 bytes
}

Advantages of RPC Testing

• Better for frontend integration
• Allows for automated testing scripts
• Can be used from any programming language
• More suitable for production applications

Event Decoding

Qubic provides an endpoint to decode events that occur during smart contract execution. This is useful for understanding what happened during transaction processing.

Event Decoding Endpoint

POST https://api.qubic.org/v1/events/decodeEvent

Example Usage

{  
  "eventType": 0,
  "eventData": "502YpKmHdvcsWG8wdVSXWdMm7aX3DmaRnqb7fwg+2jHt81Dpwpkpl7PJ6+W0KQxRwUGu55o1nGrHBs59ZdzuPOwTAAAAAAAAp1lmAQEAMwAweDA5MDM3OGE5YzgwYzVFMUNlZDg1ZTU2QjIxMjhjMWU1MTRFNzUzNTfsEwAAAAAAAAFEoI/b27Ev7KpF7C8/x+VXJvprP801z9VmZ/C4jCDTybVi2ldtkRJBIZfQbpKq0hWl/ynKZGkfwJsDf1y9XhIA"
}

Response

{
    "decodedEvent": {
        "quTransferEvent": {
            "sourceId": "NBMITJYAKMHWEHQWUULCUCRBXQPCFNFLNAHRRONUFEEHDNZDMQZUSQLBGBIN",
            "destId": "PXABYVDPJRRDKELEYSHZWJCBEFJCNERNKKUWXHANCDPQEFGDIUGUGAUBBCYK",
            "amount": "5100"
        }
    }
}

This endpoint is particularly useful for:

• Debugging transaction failures
• Understanding money flows in your smart contract
• Tracking specific events for analytics
• Verifying that your contract is behaving as expected

Project Structure

When you fork the Qubic core repository, you'll be working with this structure:

/
├── README.md                  # General information about Qubic core
├── src/                       # Source code directory
│   ├── contracts/             # Smart contract directory 
│   │   └── HM25.h             # Template smart contract file you'll modify
│   ├── contract_core/         # Core contract functionality
│   └── ...                    # Other Qubic core components

The key file you'll be modifying is src/contracts/HM25.h, which contains the template smart contract for the hackathon. Remember that after making changes to this file, you must run the cleanup script and then redeploy to see your changes take effect.

On the testnet node that we provide, you'll find the deployment scripts in this location:

/root/qubic/qubic-docker/      # Docker scripts directory on the testnet node
├── deploy.sh                  # Script to deploy your SC to a node
└── cleanup.sh                 # Script to clean up your deployment

These are the scripts you'll execute after connecting to the testnet node via SSH. Remember that after making changes to your smart contract, you must run the cleanup script and then redeploy to see your changes take effect.

FAQs

Q: Do I need to set up my own node?
A: No. We provide a test node that you can access via SSH. You'll be modifying the random.h template file on this node and deploying it using the provided scripts.

Q: How do I develop my smart contract?
A: You should fork the Qubic core repository, switch to the testnets/release-253 branch, and modify the random.h template file with your smart contract code. You can also modify files in the contract_core and contracts folders if needed, but this is not recommended for beginners.

Q: How do I test my smart contract?
A: After developing your smart contract, contact us on the #dev channel on Discord. We'll provide you with SSH access to a test node where you can run the deployment script. After successful deployment, you can use the Qubic CLI to interact with your contract.

Q: Can I update my smart contract after it's deployed?
A: Yes. Simply make your changes to the random.h file in your forked repository, and then run the deployment script again on the test node.

Q: How do I know if my smart contract has issues?
A: When you run the deployment script, it will compile your code. If there are any issues, the deployment will fail, and the logs will provide information about what went wrong.

Q: Can I build a frontend app that interacts with my smart contract?
A: Yes! After deploying your smart contract, you'll have access to an RPC endpoint that you can use to build a frontend application.

Q: Do I have to use C++ for my smart contract?
A: Yes. At this time, Qubic smart contracts must be written in C++.

Q: Will I get seeds/faucet for testing?
A: Yes! The testnet node is pre-configured with multiple pre-funded seeds, each containing 1 billion Qubic tokens. See the Available Testnet Seeds section for the complete list of seeds you can use.

Q: How do I verify my smart contract is working?
A: After deployment, use the Qubic CLI to send commands to your contract. For example:

./qubic-cli -nodeip YOUR_NODE_IP -nodeport YOUR_NODE_PORT -seed YOUR_SEED -somecommand

Q: What is the IPO process for smart contracts in Qubic?
A: On the mainnet, each smart contract needs to be IPOed and approved by computors. This is a security mechanism to ensure the quality and integrity of smart contracts. For this hackathon, we've simplified the process by providing a pre-approved template contract (HM25.h) that you can modify. You can learn more about the IPO process at https://docs.qubic.org/learn/smart-contracts.

Contact

If you have any questions or need assistance during the hackathon, please contact the team through the #dev channel on Discord.

---

This repository and documentation serve as the general resource for Qubic hackathons worldwide.