Callora is an on-chain API marketplace built on the Stellar network that enables developers to monetize APIs through pay-per-call billing in USDC.

The platform provides:

• API publishing infrastructure
• On-chain micro-payment settlement
• Usage metering
• Secure access control
• Transparent revenue distribution

Callora functions as a Web3-native API monetization layer where access to digital services is programmable and settled in real time using Stellar.

Traditional API monetization systems rely on:

• Credit cards and Stripe billing
• Monthly subscription bundles
• Centralized billing providers
• Delayed settlements
• High payment processing fees

Limitations:

• Micro-transactions below $0.01 are inefficient
• Developers in restricted regions face payment barriers
• Usage-based billing requires complex backend infrastructure
• Settlement and reconciliation are opaque

There is no decentralized infrastructure for programmable API monetization using micro-payments.

Callora introduces a prepaid access vault model:

• Developers publish APIs with pricing defined per request
• Users deposit USDC into an on-chain vault
• Each API call deducts balance programmatically
• Access tokens are issued dynamically
• Usage is verifiable and transparent

The system combines smart contracts, off-chain metering, and API gateway enforcement.

flowchart TD
    A[Developer Dashboard] --> B[API Gateway]
    C[User Application] --> B
    B --> D[Access Controller]
    B --> E[Usage Metering Service]
    E --> F[Billing Engine]
    F --> G[Soroban Smart Contract]
    G --> H[Stellar Network]
    H --> I[Horizon Listener]
    I --> J[(PostgreSQL Database)]
    F --> K[Revenue Settlement Service]
    K --> L[Developer Wallet]

Each repository has its own README with local setup instructions.