https://github.com/saucepoint/v4-constant-sum

Constant-sum AMM curve on Uniswap v4
https://github.com/saucepoint/v4-constant-sum

Last synced: about 2 months ago
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Constant-sum AMM curve on Uniswap v4

• Host: GitHub
• URL: https://github.com/saucepoint/v4-constant-sum
• Owner: saucepoint
• License: mit
• Created: 2023-12-04T15:20:21.000Z (about 1 year ago)
• Default Branch: main
• Last Pushed: 2024-03-15T11:40:03.000Z (9 months ago)
• Last Synced: 2024-08-02T16:32:22.642Z (4 months ago)
• Language: Solidity
• Size: 28.3 KB
• Stars: 11
• Watchers: 3
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-uniswap-hooks - Constant-sum Swap - sum swaps (x + y = k), allowing for an exact 1:1 swap everytime. (📜 Examples / From Community)
• awesome-uniswap-v4-resources - Constant-sum Swap - sum swaps (x + y = k), allowing for an exact 1:1 swap everytime. (📑 Table of Contents / From Community)
• awesome-uniswap-v4-resources - Constant-sum Swap - sum swaps (x + y = k), allowing for an exact 1:1 swap everytime. (📑 Table of Contents / From Community)

README

        
# v4-constant-sum

### **Constant-sum swap on Uniswap v4 🦄**

> **This repo is not production ready, and only serves as an example for custom curves on v4**

With [recent changes](https://github.com/Uniswap/v4-core/pull/404) to v4, Hooks can swap on custom curves!

`v4-constant-sum` implements constant-sum swaps (*x + y = k*), allowing for an exact 1:1 swap everytime

---

## Methodology

1. To faciliate a custom curve, we need to skip the concentrated liquidity swap. We'll use the [NoOp](https://www.v4-by-example.org/hooks/no-op) pattern, allowing us to implement the constant-sum swap.

2. The hook will hold its own token balances (as liquidity for the constant-sum curve)

3. The `beforeSwap` hook will handle the constant-sum curve:

    1. inbound tokens are taken from the PoolManager

        * this creates a debt, that is paid for by the swapper via the swap router

        * the inbound token is added to the hook's reserves

    2. an *equivalent* number of outbound tokens is sent from the hook to the PoolManager

        * the outbound token is removed from the hook's reserves

        * this creates a credit -- the swap router claims it and sends it to the swapper

---

NOTE: The tests are dependent on [v4-core#430](https://github.com/Uniswap/v4-core/pull/430)

---

Additional resources:

[v4-template](https://github.com/uniswapfoundation/v4-template) provides a minimal template and environment for developing v4 hooks

[v4-periphery](https://github.com/uniswap/v4-periphery) contains advanced hook implementations that serve as a great reference

[v4-core](https://github.com/uniswap/v4-core)