> ## Documentation Index
> Fetch the complete documentation index at: https://trust-link-tsn.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# TrustLink Labs: Building Open Payment Infrastructure

> TrustLink Labs builds TSN, TIN, GPRU, TCAP, and TrustLink Pay. Learn the mission, engineering approach, and how the protocol components fit together.

TrustLink Labs is a research and engineering organization building open payment infrastructure on Solana. Its products are the Transfer Settlement Network protocol stack and TrustLink Pay, the reference application built on top of it.

## Mission

> Build the protocol stack that makes stablecoin payments as intuitive as modern banking while preserving user ownership, privacy, and open blockchain principles.

## Products

**TSN** (Transfer Settlement Network) is the core protocol: an identity-first, intent-based, privacy-preserving settlement layer for stablecoin and digital asset transfers on Solana. It provides identity-aware authorization, treasury-backed settlement, and confidential balance accounting.

**TrustLink Pay** is the reference application built on TSN. It demonstrates the end-to-end integration for developers who want to embed TSN payment flows in their own products.

## Protocol components

| Component       | Role                                                                                      |
| --------------- | ----------------------------------------------------------------------------------------- |
| **TSN**         | Coordinates authorization, leases, epoch liability, and settlement execution              |
| **TIN**         | Transfer Identity Number: portable 10-digit payment identity                              |
| **TIP**         | Transfer Identity Protocol: issues and resolves TIN relationships                         |
| **GPRU**        | Non-custodial authorization and routing scope; never holds funds                          |
| **TCAP**        | Transfer Confidential Asset Protocol: credit-only tip transitions and encrypted snapshots |
| **Stable-TCAP** | Devnet-only test asset; valueless; not USDC                                               |

## Engineering approach

TrustLink Labs combines AI-assisted engineering with human-led architecture. Protocol design, security review, and boundary definitions are set by the maintainer team. Implementation, testing, and documentation use AI tooling under human review. This lets a small team ship at the pace of a larger one without sacrificing the discipline that a payment protocol requires.

## Resources

<CardGroup cols={2}>
  <Card title="GitHub" icon="github" href="https://github.com/Trustlink-Labs">
    TrustLink Labs organization on GitHub.
  </Card>

  <Card title="TrustLink Pay" icon="wallet" href="https://github.com/bigdreamsweb3/trustlink-pay">
    Reference application repository.
  </Card>

  <Card title="Research Library" icon="book" href="https://github.com/Trustlink-Labs/Trustlink-Research">
    Open protocol research and analysis.
  </Card>

  <Card title="TSN Blog" icon="rss" href="https://tsn-protocol.blogspot.com">
    Long-form TSN protocol writing.
  </Card>

  <Card title="X" icon="x-twitter" href="https://x.com/TrustLinkLabs">
    Follow @TrustLinkLabs.
  </Card>

  <Card title="What We're Building" icon="cubes" href="/about/what-were-building">
    Concrete artifacts and current scope.
  </Card>
</CardGroup>