> ## Documentation Index
> Fetch the complete documentation index at: https://docs.train.tech/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> A trustless, permissionless cross-chain bridging (swapping) solution.

The **TRAIN** Protocol (**TR**ustless **A**tomic **IN**tents) is a peer-to-peer system for bridging and swapping crypto assets between blockchain networks. The protocol is implemented as a set of persistent, non-upgradable smart contracts deployed to all [supported networks](https://docs.train.tech/deployments.md).

* TRAIN is built on top of [HTLC with recoverable secret generation](https://docs.train.tech/protocol/atomic-swaps-secret_gen.md). This allows two parties—the **User** and the **Solver**—to exchange assets trustlessly across different chains. Users send their **Intents** to Solvers, who fulfill these Intents using Atomic Swaps.
* There are **no third parties or gatekeepers**. The security of the exchange is fully ensured by:
  * The cryptographic protocol (Atomic Swaps)
  * Local verification through a [Light Client](https://docs.train.tech/protocol/dApp.md) running in the User's browser

> [card] [Try TRAIN in Action](https://testnet.train.tech/)
>
> Experience TRAIN on all major network testnets, including EVM-compatible chains, Starknet, Solana, and Fuel.

> [card] [Protocol Concepts](https://docs.train.tech/protocol/the-protocol.md)
>
> Explore the core protocol concepts: Users, Solvers, Auctions, and Atomic Swaps.

> [card] [Protocol Spec](https://docs.train.tech/protocol-spec)
>
> Dive deeper into the protocol specification and detailed protocol design.


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.