⚡️ Solana DEX Protocol

A capital-efficient DEX protocol on Solana featuring weighted AMM pools and SPL-token-powered on-chain routing. It includes:

• Weighted constant-product swap logic (Balancer-style)
• Real SPL token integration via CPI
• PDA-managed vaults for secure token custody
• Weighted pool math using fixed-point arithmetic (u128)
• Multi-hop routing-ready architecture
• End-to-end Anchor tests with minting, ATAs, and swaps

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🧠 Overview

This protocol simulates the routing engine of a DEX aggregator like Jupiter or Stabble, using weighted pools and SPL token CPIs to simulate token swaps between two tokens with arbitrary weights (e.g., 80/20 or 60/40 pools).

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📦 Features

✅ Weighted pool routing using:
amountOut = y * (1 - (x / (x + amountIn)) ^ (wx / wy))

✅ Vaults managed by PDA-controlled accounts
✅ Real SPL token support (via CPI to token program)
✅ Fully tested using dynamic token minting
✅ Written in Rust using Anchor framework

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🛠️ Tech Stack

• 🔁 Solana Program Library (SPL)
• 🧵 Anchor framework for Solana development
• 🧠 Fixed-point math using u128 precision
• 🧪 Anchor Mocha tests (TypeScript)
• 🪙 SPL Token integration for real swaps

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📁 Directory Structure

├── programs/
│ └── dex_router/
│ ├── src/
│ │ ├── lib.rs # Anchor entrypoint
│ │ ├── context.rs # Account constraints
│ │ ├── errors.rs # Errors
│ │ ├── state.rs # Pool struct and constants
│ │ ├── processor.rs # Instruction logic
│ │ └── math.rs # Fixed-point weighted pool math
├── tests/
│ └── dexrouter.ts # Minting, pool init, weighted swap
├── Anchor.toml
├── Cargo.toml
└── README.md

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🚀 Local Setup

# Clone the repo
git clone https://github.com/tdadadavid/DEXRouter.git
cd DEXRouter

# Install dependencies
anchor build
anchor test

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🧪 Tests

Run full tests (mint tokens, setup ATAs, initialize pool, swap):

anchor test

Each test:

• Creates two SPL mints
• Mints tokens to the payer
• Initializes a pool with 50/50 weights
• Executes a CPI-based swap from token A → token B

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📐 Math Model

We implement weighted swap math from the Balancer V1 model:

amountOut = tokenOutBalance * (1 - (tokenIn / (tokenIn + amountIn)) ^ (weightIn / weightOut))

Implemented via a custom pow_fixed() helper using u128 fixed-point math with 18 decimal precision. Supports stable and safe execution in BPF-constrained environments.

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🔐 Security Notes

• Vault accounts are owned by a deterministic PDA (pool_signer)
• Users only interact with program-controlled SPL token vaults
• Token movements are done via secure CPI to the spl-token program

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🧠 Inspiration

This project is inspired by the routing engines and pool math behind:

• Balancer
• Jupiter Aggregator
• Stabble Protocol