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

# Architecture Overview

> The stack, the on-chain/off-chain boundary, and how the pieces fit.

Hyro Protocol is a modular system: a small on-chain core, two pluggable on-chain layers, and an off-chain execution + oracle stack that writes results back to Solana.

## The stack

| Layer                       | Technology                                                                |
| --------------------------- | ------------------------------------------------------------------------- |
| Blockchain                  | Solana                                                                    |
| Smart contract framework    | Anchor 0.31.1                                                             |
| Frontend                    | Next.js + TypeScript                                                      |
| Oracle transport            | NATS with JetStream                                                       |
| Client SDK generation       | Codama (from Anchor IDLs)                                                 |
| Off-chain venue integration | CCXT (Bybit live; others in progress)                                     |
| Off-chain engine            | Rust (HyroTrader core engine)                                             |
| Wallet — pro users          | Phantom (self-custody)                                                    |
| Wallet — retail             | Embedded (email signup, auto-generated Solana wallet via Privy / Dynamic) |
| Settlement currency         | USDC (SPL)                                                                |
| Gas                         | Sponsored by Hyro — users never need SOL                                  |
| Audit                       | Ackee Blockchain                                                          |

## The dual-wallet UX

Email-based account creation produces a Solana wallet automatically — no extension, removing onboarding friction for retail traders coming from CeFi. Sophisticated managers use Phantom for full self-custody. Users can export keys or migrate to Phantom at any time. Gas sponsorship is a fractional-cent operational cost on Solana that meaningfully improves UX.

## On-chain vs. off-chain

<Columns cols={2}>
  <Card title="On-chain (Solana)" icon="link">
    Vault state · authorization (policy programs) · fee calculation · share accounting · LP deposits/withdrawals · payout records · challenge-fee collection
  </Card>

  <Card title="Off-chain" icon="server">
    Trade execution (Bybit order books) · the Rust risk engine · NAV computation, which the oracle writes back on-chain
  </Card>
</Columns>

## How the layers connect

The core program (`hyro_protocol`) holds vault state and orchestrates two pluggable layers over CPI:

1. **Authorization** — every privileged instruction issues a `validate(ValidateOperation)` CPI into the vault's policy.
2. **Fee calculation** — every fund movement issues a `charge_fees` CPI to the fee dispatcher, which delegates arithmetic to a calculator.

Neither is hard-coded. Each vault stores only the pubkeys of its `policy_program` and `fee_collection_program`, and both are swappable.

<Card title="Program topology" icon="git-fork" href="/reference/program-topology" horizontal>
  How the on-chain programs connect, instruction by instruction.
</Card>