Traditional accounting relies on double-entry bookkeeping - a system where each party maintains separate ledgers, creating potential for discrepancies and requiring reconciliation. Bulla Network introduces a paradigm shift by implementing triple-entry accounting through blockchain technology, where financial relationships are represented as NFTs on a shared, immutable ledger.

At its core, Bulla transforms invoices, loans, and IOUs into programmable tokens, enabling a new class of financial applications built on verifiable, shared state.

Bulla's architecture centers around a foundational contract (BullaClaim) that handles core claim operations, with specialized "controller" contracts that add domain-specific functionality. This design enables infinite extensibility while maintaining a stable foundation.

BullaClaim (Foundation Layer)
├── BullaInvoice (Business Invoicing)
├── BullaFrendLend (Peer-to-Peer Lending)
└── Custom Controllers (Unlimited Extensions)

BullaClaim.sol serves as the protocol's foundation, implementing:

• NFT-based Claims: Each financial obligation becomes an ERC-721 token owned by the creditor

• Comprehensive State Management: Tracks claim amounts, payment history, due dates, and binding status

• Permission System: Granular approvals allowing smart contracts to act on users' behalf

• Status Lifecycle: Claims progress through states (Pending → Repaying → Paid/Rejected/Rescinded/Impaired)

Key Data Structures:

struct Claim {
    uint256 claimAmount;
    uint256 paidAmount;
    address creditor;
    address debtor;
    address token;
    Status status;
    ClaimBinding binding;
    // ... additional fields
}

Controllers delegate core operations to BullaClaim while implementing specialized business logic. This pattern provides several advantages:

• Separation of Concerns: Core claim mechanics remain stable while business logic evolves

• Gas Efficiency: Controllers can be stateless, minimizing storage costs

• Composability: Multiple controllers can interact with the same underlying claims

• Upgradeability: New features can be added without touching the foundation

BullaInvoice.sol extends basic claims with sophisticated business features:

Compound Interest System:

• Configurable interest rates and compounding periods

• Late fee calculation based on due dates

• Real-time interest accrual for active claims

Purchase Orders:

• Deposit requirements for commitment

• Delivery date tracking

• Automatic binding when deposits are fully paid

Protocol Economics:

• Fee collection from interest payments

• Origination fees for invoice/purchase order creation

• Admin functions for fee management

Example Flow:

1. Creditor creates invoice: "Debtor owes $1000, due in 30 days, 5% monthly late fee"

2. Invoice exists as pending claim NFT

3. After due date, interest accrues automatically

4. Debtor pays $1050 (principal + interest), protocol takes fee from interest

5. Claim marked as paid, optionally transferred to debtor as receipt

BullaFrendLend.sol implements a marketplace for direct lending:

Loan Offers/Requests:

• Users can offer loans to specific counterparties

• Or request loans that others can accept

• Terms include amount, interest rate, duration

Automatic Execution:

• When loan is accepted, funds transfer immediately

• Claim NFT created with repayment terms

• Interest accrues from acceptance timestamp

Risk Management:

• All loans are automatically "bound" (both parties explicitly agreed)

• Interest calculation using shared compound interest library

• Protocol fees collected from interest payments

Example Flow:

1. Alice offers: "I'll lend Bob $5000 USDC at 8% APR for 6 months"

2. Bob accepts the offer

3. Smart contract transfers $5000 from Alice to Bob

4. Claim NFT created: "Bob owes Alice $5000 + interest, due in 6 months"

5. Bob can repay anytime; early payment reduces total interest

Making claims into NFTs provides powerful composability:

• Transferability: Creditors can sell unpaid invoices (factoring)

• Collateralization: Claims can be used as collateral in DeFi protocols

• Programmability: Smart contracts can hold and manage claims

• Receipt System: Paid claims can transfer to debtors as proof of payment

Claims can be "bound" or "unbound":

• Unbound: Debtor hasn't explicitly agreed (like sending someone an invoice)

• Bound: Both parties have agreed to the obligation

• BindingPending: Creditor requests debtor acceptance

This distinction creates stronger social/legal obligations for bound claims while allowing for dispute resolution on unbound ones.

Users can pre-approve smart contracts for various operations:

• Create Claims: "PayrollContract can create 50 salary claims up to $5K each"

• Pay Claims: "AutopayContract can pay my utility bills from my wallet"

• Manage Claims: Approve binding updates, cancellations, etc.

This enables full automation while maintaining user custody and control.

• B2B Invoicing: Automated invoice creation and payment tracking

• Payroll Management: Batch salary payments with automatic record-keeping

• Vendor Payments: Supply chain finance with payment scheduling

• Subscription Billing: Recurring payment automation

• Invoice Factoring: Sell unpaid invoices for immediate liquidity

• Credit Scoring: On-chain payment history for lending decisions

• Collateralized Lending: Use claims as collateral for loans

• Insurance Products: Protect against non-payment risk

Bulla generates revenue through:

• Origination Fees: Fixed fees for creating invoices/loans (paid in ETH)

• Protocol Fees: Percentage of interest payments across all tokens

• Premium Features: Enhanced functionality for enterprise users

This model aligns protocol incentives with user success - revenue grows as the ecosystem processes more financial activity.

• No Custody: Protocol never holds user funds beyond transaction processing

• No Accounts: Users interact directly with smart contracts using wallets

• Open Source: All code is publicly auditable

• Permissionless: Anyone can build controllers or integrate

Bulla Network represents a fundamental reimagining of financial record-keeping for the digital age. By making financial relationships programmable and composable, the protocol enables new classes of applications that were impossible in traditional finance.

The controller architecture ensures the protocol can evolve with user needs while maintaining a stable foundation. As the ecosystem grows, we expect to see innovative applications in areas like supply chain finance, international trade, DeFi integration, and automated business operations.

Most importantly, Bulla maintains the core principles of decentralization - users retain custody of their assets while benefiting from shared, verifiable financial records. This creates the foundation for a more transparent, efficient, and globally accessible financial system.