# 01 - Protocol Overview
## What is Sperax?
Sperax is a DeFi protocol ecosystem built primarily on **Arbitrum** (Layer 2) consisting of:
1. **USDs** - An auto-yield stablecoin that grows in your wallet
2. **SPA** - Governance token with deflationary mechanics
3. **veSPA** - Vote-escrowed SPA for governance voting
4. **xSPA** - Reward token redeemable for SPA
5. **Demeter** - No-code yield farm deployer
---
## USDs: Auto-Yield Stablecoin
### Core Features
| Feature | Description |
|---------|-------------|
| **Collateralization** | 100% backed by USDC, USDC.e, USDT |
| **Auto-Yield** | Balance grows automatically via rebase (~25% APY) |
| **No Staking Required** | Yield accrues to all EOA holders |
| **Yield Source** | Collateral deployed to DeFi protocols |
### How Auto-Yield Works
```
┌─────────────────┐
│ User holds │
│ 100 USDs │
└────────┬────────┘
│
▼
┌─────────────────┐ ┌─────────────────┐
│ Collateral in │────▶│ Yield earned │
│ Aave/Compound │ │ from lending │
└─────────────────┘ └────────┬────────┘
│
┌────────────┴────────────┐
▼ ▼
┌───────────────┐ ┌───────────────┐
│ 70% → Rebase │ │ 30% → Buyback │
│ (to holders) │ │ (burn SPA) │
└───────┬───────┘ └───────────────┘
│
▼
┌─────────────────┐
│ User now has │
│ 100.05 USDs │
│ (after rebase) │
└─────────────────┘
```
### Yield Distribution Split
| Destination | Percentage | Purpose |
|-------------|------------|---------|
| USDs Holders | 70% | Auto-yield via rebase |
| SPA Buyback | 30% | Buy & burn SPA (deflationary) |
### Yield Sources (Strategies)
| Strategy | Protocol | Risk Level |
|----------|----------|------------|
| AaveStrategy | Aave V3 | Low |
| CompoundStrategy | Compound V3 | Low |
| StargateStrategy | Stargate Finance | Medium |
| FluidStrategy | Fluid Protocol | Medium |
---
## Mint & Redeem Flow
### Minting USDs
```
User deposits USDC ──▶ VaultCore.mint() ──▶ User receives USDs
│
├── Collateral → Strategy (yield)
├── Mint fee collected
└── USDs minted 1:1 (minus fee)
```
**Supported Collaterals**:
- USDC (Native)
- USDC.e (Bridged)
- USDT
- DAI
- FRAX
- LUSD
### Redeeming USDs
```
User burns USDs ──▶ VaultCore.redeem() ──▶ User receives USDC
│
├── USDs burned
├── Redeem fee collected
└── Collateral returned from strategy
```
### Fee Structure
| Operation | Base Fee | Dynamic Adjustment |
|-----------|----------|-------------------|
| Mint | 0.0% - 0.1% | Lower if collateral below target |
| Redeem | 0.1% - 0.5% | Higher if collateral below target |
---
## SPA Tokenomics
### Token Utility
| Use Case | Description |
|----------|-------------|
| Governance | Vote on protocol parameters via veSPA |
| Staking Rewards | Earn xSPA rewards for locking SPA |
| Buyback & Burn | 30% of yield buys and burns SPA |
### Deflationary Mechanics
```
Collateral Yield
│
└── 30% ──▶ SPABuyback Contract
│
├── Buy SPA from market
│
└── 50% Burn SPA
50% → veSPA Rewards
```
### Token Supply
| Metric | Value |
|--------|-------|
| Initial Supply | 5,000,000,000 SPA |
| Burned to Date | 375,000,000+ SPA |
| Circulating | Dynamic (check Arbiscan) |
---
## veSPA: Vote-Escrowed SPA
### Lock Mechanics
```solidity
// Lock formula
veSPA = SPA_amount × (lock_days / 365)
// Examples:
// 1000 SPA locked 1 year = 1000 veSPA
// 1000 SPA locked 4 years = 4000 veSPA
// 1000 SPA locked 7 days = 19.18 veSPA
```
### Lock Parameters
| Parameter | Value |
|-----------|-------|
| Minimum Lock | 7 days |
| Maximum Lock | 4 years (1461 days) |
| veSPA Decay | Linear to expiry |
### veSPA Benefits
1. **Governance Voting** - Vote on Snapshot proposals
2. **Revenue Share** - Receive SPA from buyback
3. **Boosted Rewards** - Higher APR in Demeter farms
---
## xSPA: Reward Token
### Redemption Mechanics
xSPA can be redeemed for SPA with a vesting period:
```solidity
// Redemption formula
SPA_out = xSPA_amount × (vesting_days + 150) / 330
// Examples:
// 100 xSPA, 15-day vest = 50 SPA (50%)
// 100 xSPA, 90-day vest = 72.7 SPA (72.7%)
// 100 xSPA, 180-day vest = 100 SPA (100%)
```
### Redemption Schedule
| Vesting Period | SPA Received |
|----------------|--------------|
| 15 days (min) | 50% |
| 30 days | 54.5% |
| 60 days | 63.6% |
| 90 days | 72.7% |
| 120 days | 81.8% |
| 150 days | 90.9% |
| 180 days (max) | 100% |
---
## Demeter: No-Code Farms
### Overview
Demeter allows anyone to create yield farms for their LP tokens without coding.
### Farm Types
| Type | Description |
|------|-------------|
| E20Farm | ERC-20 LP token farms |
| E721Farm | NFT position farms (Uniswap V3, Camelot) |
| CamelotV2Farm | Camelot DEX LP farms |
| CamelotV3Farm | Camelot V3 concentrated liquidity |
| UniswapV3Farm | Uniswap V3 position farms |
### Creation Fee
| Parameter | Value |
|-----------|-------|
| Creation Fee | 100 USDs |
| Extension Fee | 1 USDs/day |
| Fee Receiver | SPABuyback contract |
### Farm Features
- **Lockup Option**: Optional cooldown period (0-30 days)
- **Multi-Reward**: Up to 4 reward tokens per farm
- **APR-Based Rewards**: Via Rewarder contract
- **Expirable Farms**: Optional expiry with extension
