
Building Trust and
Authorization with Blockchain for
AI-Driven Payments

Enabling secure payments in the agent economy
SemanticPay set out to redefine how people and businesses execute payments in an AI-driven world.
The team envisioned a system where AI agents can securely act on behalf of users, combining decentralized identity, blockchain, and artificial intelligence into a single payment flow.
At an early stage of product development, SemanticPay required a working prototype to validate the concept and demonstrate its feasibility to partners such as the Stellar Development Foundation and potential investors.
Verifying agent authority without sacrificing simplicity
The core challenge centered on a fundamental question: How can an AI agent be verified as legitimately authorized to act on behalf of a human or organization?

To answer this, SemanticPay needed to:
Link a verifiable decentralized identity with real payment transactions
Ensure agents can act securely and transparently within defined permissions
Orchestrate identity, wallets, blockchain, and AI without overwhelming users
Maintain strong security guarantees while keeping the experience intuitive
Balancing cryptographic rigor with usability was critical to the product’s success.
Decentralized identity and blockchain as the foundation of trust
Decentralized identity was the core trust layer of the entire Semantic Pay system. We designed a blockchain-based identity and authorization model that addresses a critical requirement of the agent economy: proving not only who someone is, but also what they are authorized to do.
Take a look of how it works:
Decentralized identities anchored to blockchain, eliminating reliance on centralized authorities.
Smart contract–driven permissions, defining exactly how AI agents can act on a user’s behalf.
Wallet-linked authorization, binding identity directly to real transaction execution.
Scoped and revocable access, giving users full control over agent behavior.
By enforcing identity and authorization at the smart contract level, trust and accountability become protocol guarantees — not off-chain assumptions.
The result.
Secure, auditable, and automated payments that empower AI agents while keeping users firmly in control.
A programmable authorization layer for AI agents
Building on this decentralized foundation, we designed and implemented a modular architecture that enables secure agent authorization and automated transactions.
Key pillars of the solution included:
Blockchain architecture and smart contracts for identity, wallets, and authorization
Wallet automation, allowing users to delegate transaction signing to AI agents
Granular permissions and authentication, defining exactly what agents can do
Model Context Protocol (MCP) as an orchestration layer connecting AI, blockchain, and data.
End-to-end web application, showcasing real-world usage of the system.


Making advanced infrastructure feel effortless
The final prototype demonstrated the full identity-to-payment flow, proving that AI agents can safely and transparently operate within defined user permissions.




Key pillars of the solution included:
The final prototype demonstrated the full identity-to-payment flow, proving that AI agents can safely and transparently operate within defined user permissions.
All required smart contracts for identities, wallets, and authorization.
A wallet automation system enabling agent-based transaction signing.
Permissions and authentication mechanisms for agents.
An MCP Server interacting with smart contracts, database, Claude model, and the Stellar network.
A complete web application demonstrating the MCP Server in action.







Technologies: built for security, interoperability, and scale
Blockchain
Stellar smart contracts written in Rust
Stellar SDK for off-chain interactions
Backend
Node.js and TypeScript
PostgreSQL
Claude Sonnet 4 model
OWASP and W3C standards for decentralized identity
Frontend
React
Vite
Infrastructure for the next generation of payments
SemanticPay lays the groundwork for a future where AI agents transact responsibly, transparently, and securely—unlocking new possibilities for automation, commerce, and digital trust.

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