Project Funding Smart Contract

A decentralized project funding platform built on the Stacks blockchain using Clarity smart contracts. This contract enables transparent project creation, funding, and expenditure tracking with role-based access control.

Overview

This smart contract facilitates crowdfunding projects where:

• Managers can create funding projects
• Contributors can fund projects with STX tokens
• Owners can track and validate project expenditures
• All transactions are recorded transparently on-chain

Features

Core Functionality

• Project Creation: Create projects with funding goals and descriptions
• Decentralized Funding: Accept STX contributions from any wallet
• Expenditure Tracking: Record and approve project expenses
• Role-Based Access: Three-tier permission system
• Transparent Records: All funding and spending is publicly verifiable

Access Levels

1. ACCESS-OWNER (Level 1): Full administrative rights
   • Assign/revoke access levels
   • Validate expenditures
   • Record expenditures
2. ACCESS-MANAGER (Level 2): Project management rights
   • Create new projects
3. ACCESS-PARTICIPANT (Level 3): Basic participant rights
   • View project information
   • Fund projects (anyone can fund, regardless of access level)

Contract Functions

Project Management

• create-project(title, details, funding-goal) - Create a new funding project
• get-project(id) - Retrieve project information by ID

Funding Operations

• fund-project(project-id, value) - Contribute STX to a project
• get-contribution-by-id(contribution-id) - Get contribution details
• get-contribution-total() - Get total number of contributions

Expenditure Tracking

• record-expenditure(project-id, details, value) - Record project expense
• validate-expenditure(project-id, phase) - Approve recorded expenditure
• get-expenditure-by-id(expenditure-id) - Get expenditure details
• get-expenditure-total() - Get total number of expenditures

Access Control

• assign-access(account, new-level) - Grant access level to user
• revoke-access(account) - Remove user's access level

Data Structures

Projects

{
  title: string-utf8 50,
  details: string-utf8 255,
  funding-goal: uint,
  funds-raised: uint,
  state: string-ascii 20
}

Contributions

{
  contributor: principal,
  project-id: uint,
  value: uint,
  block-time: uint
}

Expenditures

{
  project-id: uint,
  phase: uint,
  details: string-utf8 255,
  value: uint,
  state: string-ascii 20
}

Error Codes

• u100 - Unauthorized access attempt
• u101 - Duplicate entry error
• u102 - Entry not found
• u103 - Insufficient balance
• u104 - Project not found
• u105 - Expenditure not found
• u106 - Invalid input parameters

Security Features

• Role-based permissions: Prevents unauthorized actions
• Input validation: Ensures data integrity
• Overflow protection: Safe arithmetic operations
• Self-modification protection: Users cannot modify their own access levels
• Fund safety: STX tokens are held securely in contract

Usage Example

1. Deploy Contract: Admin automatically receives ACCESS-OWNER level
2. Assign Managers: (assign-access 'SP1ABC... ACCESS-MANAGER)
3. Create Project: (create-project "Mobile App" "Revolutionary new app" u1000000)
4. Fund Project: (fund-project u1 u50000)
5. Record Expense: (record-expenditure u1 "Development costs" u25000)
6. Validate Expense: (validate-expenditure u1 u1)

Deployment Notes

• Contract admin is set to the deploying principal
• Admin automatically receives ACCESS-OWNER permissions
• All counters start at 0
• Projects begin with "active" state
• Expenditures begin with "pending" state

Security Considerations

• Only contract admin can assign/revoke access levels
• Expenditures require validation before approval
• Cannot approve expenditures exceeding available funds
• All role assignments are logged and traceable
• Input validation prevents malformed data entry