Architecture

Frgmnt transforms idle stablecoins into productive assets. When you deposit stablecoins like USDC, DAI, or USDT, you receive fUSD the protocol's native stablecoin. Stake your fUSD to receive sfUSD, a yield-bearing token that automatically grows in value as the protocol generates returns.

The simple flow:

Your Stablecoins → fUSD → sfUSD → Yield

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Core Components

1. fUSD : The Foundation

fUSD is your entry point into the Frgmnt ecosystem. It's a 1:1 backed stablecoin minted when you deposit approved assets.

How it works:

• Deposit USDC, DAI, USDT, or other approved stablecoins

• Receive fUSD at the current USD value (via oracle pricing)

• Your deposited assets flow into the staking pool

fUSD serves as the stable unit of account within Frgmnt : always representing a claim on real stablecoin value.

2. sfUSD : The Yield Layer

sfUSD is where the magic happens. It's a share token representing your proportional ownership of the staking pool.

Key features:

• Stake fUSD to mint sfUSD shares

• Dual yield system : earn from both share price appreciation AND harvestable fUSD rewards

• Harvest anytime : claim your accumulated fUSD yield without touching your principal

• Flexible exit : unstake to receive your proportional share of pool assets

How yield works:

sfUSD uses a unique two-layer yield model:

1. Share price appreciation: As the pool generates returns, your sfUSD shares become worth more fUSD over time

2. Harvestable rewards: Price growth is also tracked in a separate accumulator, letting you harvest() fUSD gains without unstaking

This means you can either let everything compound, or regularly harvest yields while keeping your position.

Why shares instead of rebasing? Your sfUSD balance stays constant while its value increases. This is simpler for DeFi integrations, tax tracking, and mental accounting.

3. Pool Manager : The Control Center

The Pool Manager governs what happens inside each pool:

• Which assets can be deposited

• Fee structures (entry, exit, performance, management)

• Access controls and membership rules

• Asset valuations and compositions

This separation allows pools to be customized for different strategies while maintaining consistent security standards.

4. Governance : The Security Layer

The Governance contract acts as the protocol's security registry:

• Defines which external protocols can be integrated

• Assigns guards to contracts and asset types

• Ensures all interactions pass security validation

Every transaction the protocol makes is checked against these guards before execution.

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System Architecture Diagram

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The User Journey

Depositing & Staking

1. Approve your stablecoins for the fUSD contract

2. Deposit your stablecoins are transferred to the pool, you receive fUSD

3. Stake lock your fUSD in the sfUSD contract to receive shares

4. Earn your shares automatically accumulate yield

Harvesting Yield

sfUSD tracks token price growth in a separate accumulator. When the share price increases (from strategy gains, fees, etc.), that growth is recorded per-share. Call harvest() at any time to claim your accumulated fUSD : your principal stays staked and continues earning.

Withdrawing

Immediate Mode:

• Burn your sfUSD shares

• Receive your proportional share of pool assets

• Exit fee (in shares) goes to the protocol

Queued Mode (if enabled):

• Request a withdrawal, locking your shares

• Manager finalizes the withdrawal with a fixed fUSD amount

• Claim your fUSD when ready

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Security Model

Frgmnt is built with multiple layers of protection:

Layer	Protection
Role Separation	Distinct manager, trader, and governance roles with limited permissions
Guard System	All external calls validated through contract and asset guards
Reentrancy Protection	Critical functions protected against reentrancy attacks
Upgrade Safety	UUPS pattern with governance-controlled upgrades
Fee Delays	Fee increases require announcement period before taking effect
Cooldowns	Prevents flash loan and MEV exploitation

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Fee Structure

Fees are applied as share dilution, your balance isn't cut, but the total share supply increases:

Fee Type	Description	Current Fee
Entry Fee	Applied when staking fUSD for sfUSD	0%
Exit Fee	Applied when unstaking sfUSD	0%
Performance Fee	Percentage of profits, minted as shares	20%
Management Fee	Streaming fee on AUM, minted as shares	0%

This approach is gas-efficient and doesn't require touching user balances.