Smart Contracts Overview - YouthChain

All contracts are written in Solidity, compiled with Foundry, and deployed to the testnet EVM. They are regular EVM contracts — nothing exotic, no precompiles required to use them (though the EngagementScore precompile at 0x0A is available for gas optimization).

Addresses (public testnet, chain ID 7717)

Source of truth: contracts/script/deployed.json (deployed 2026-05-22).

Contract	Address
YCEToken	`0x6a2247af143536d3ce0b9bf86a27c9b366e2f9ed`
YCRRewards	`0x6afd8143a2d213067a31abe5adf0d458a0df532b`
EngagementDrivenConverter (AMM)	`0xb7646654d1fd946e8a8bc32b5786a571be5925f2`
BurnManager	`0x27cb5d2d2cedaf1274730edd348ad0c6eb003fdb`
StakingJars	`0xb11688e8ab9f2f32ece6ac663655ce7d7603a482`
QuadraticVoting (DAO, 5min testnet voting)	`0xa5851461a5cff6f8277917f2a691d3c6ef5bef9e`
ValidatorRegistry	`0x286b9783b3245a253c3350c60d91cd50cc5e4c5c`
EngagementOracle	`0x06df136b8fbdbf93be1271dbd1b7a52854d7c6a9`
YouthNameService (`.yc` handles)	`0xcc79b3ecae6f9928ddcf764c28789a8a9a572805`
EngagementRollup v2	`0xefca508817f94af9d348250471046a0bcd476aef`
YCE721 (NFT)	`0x82f89f43f91eb0eb9df5867c5aa49402bc947643`
StYCE (ERC-4626 liquid staking)	`0x197d9cd2268cfc20840c6a7ca9113b641b7b901d`

The deployed.json shipped in contracts/script/deployed.json is always the source of truth. dao_voting_period_secs: 300 confirms the testnet DAO has a 5-minute voting window so execute() can be exercised in a single test session.

These addresses can change between testnet resets (every chain wipe redeploys). Always read them from the network stats endpoint in production clients.

How they interact

  Mobile App ──▶ /api/mobile/engagement ──▶ EngagementOracle.recordAction()
                                                  │
                                                  ▼
                                      score(user) updated
                                                  │
                      ┌───────────────────────────┼───────────────────────────┐
                      ▼                           ▼                           ▼
              StakingJars                 QuadraticVoting               ValidatorRegistry
         (reward weight = stake × ES)   (vote weight = sqrt(ES))   (leader weight = stake × (1+β·ES))

  Solidity contracts read ES via precompile 0x0A during EVM execution.
  Node leader selection uses the node's in-memory engagement counter — not the precompile.

Deployment

All contracts are redeployed on every testnet reset via the contracts/script/deploy_full.sh script. The deployer is test account #1. ABIs are emitted to contracts/out/ after forge build.

ABI access

cd contracts && forge build
cat out/YCEToken.sol/YCEToken.json | jq .abi

import { Interface } from "ethers";
import abi from "./YCEToken.abi.json" assert { type: "json" };
const iface = new Interface(abi);