The Sky Protocol—originally launched in 2015 as MakerDAO—is one of the most influential decentralized finance (DeFi) systems on Ethereum. Designed through global collaboration, it introduced the world’s first decentralized stablecoin backed by crypto collateral. Over time, the ecosystem evolved from a single-collateral system into a multi-asset powerhouse, rebranded in 2024 as Sky, with new innovations like USDS, RWA vaults, and advanced governance mechanisms.
This whitepaper outlines the core architecture of the Sky ecosystem, focusing on its stablecoins (Dai and USDS), vault mechanics, risk management, governance model, and integration of real-world assets (RWAs). Written primarily in 2019 but updated to reflect key developments through 2025, it serves as a foundational guide to understanding how Sky maintains stability, decentralization, and scalability in an ever-changing financial landscape.
Understanding the Sky Protocol
The Sky Protocol operates as a decentralized application (dapp) on the Ethereum blockchain, enabling users to generate Dai, a soft-pegged USD stablecoin, by locking digital assets as collateral. Governed by MKR token holders, the protocol uses smart contracts known as Vaults to facilitate over-collateralized debt positions—ensuring every Dai in circulation is backed by excess value.
Sky stands out for its robust risk frameworks, transparent governance, and pioneering integration of real-world assets into DeFi. Its ecosystem includes multiple stablecoins, automated auction systems, and a dynamic savings rate mechanism that adjusts to market conditions.
Core Features of the Sky Ecosystem
- Decentralized Governance via MKR
- Dual Stablecoins: Dai and USDS
- Multi-Collateral Support (MCD System)
- Real-World Asset (RWA) Integration
- Automated Risk Mitigation & Auctions
- Dai Savings Rate (DSR) and Sky Savings Rate (SSR)
These components work together to create a resilient financial infrastructure capable of adapting to global economic shifts while maintaining trustless operations.
The Dai Stablecoin: A Decentralized Store of Value
Dai is a decentralized, unbiased cryptocurrency soft-pegged to the US dollar. Unlike centralized stablecoins backed by fiat reserves, Dai is fully collateral-backed by digital assets locked within Sky Protocol Vaults. This design ensures censorship resistance, transparency, and global accessibility.
How Dai Functions Like Money
Dai fulfills all four traditional functions of money:
- Store of Value – Designed to maintain purchasing power even during crypto market volatility.
- Medium of Exchange – Accepted across thousands of platforms for payments, trading, and DeFi interactions.
- Unit of Account – Used internally in dapps and protocols for pricing services and tracking balances.
- Standard of Deferred Payment – Enables users to settle debts (e.g., stability fees) within the protocol.
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Every Dai is over-collateralized and backed by excess value locked in Vaults. Transactions are publicly verifiable on-chain, reinforcing trust and auditability.
Introducing USDS: The Next-Gen Stablecoin
Launched alongside Sky’s 2024 rebranding, USDS expands the ecosystem with enhanced scalability and regulatory preparedness.
Key Differences Between Dai and USDS
While both are USD-pegged and collateral-backed, USDS introduces forward-looking features:
- Proxy-Upgradable Architecture: Built using ERC1967Proxy standard, allowing future upgrades via governance votes.
- Potential Freeze Functionality: Not yet active, but可 be enabled through decentralized governance if needed to comply with legal frameworks in certain jurisdictions.
- Transparent Appeals Process: Any freeze would involve public deliberation and a decentralized appeals mechanism for fairness.
- Seamless Conversion: Users can freely convert between Dai and USDS via a built-in converter contract.
This design ensures USDS can scale globally while balancing decentralization with compliance readiness.
How to Acquire USDS
Users can obtain USDS through:
- Direct conversion from Dai
- Earning via the Sky Savings Rate (SSR)
- Receiving Sky Token Rewards (STR)
- Purchasing on decentralized exchanges (DEXs) or centralized platforms
The SSR operates similarly to the DSR but leverages the ERC4626 tokenized vault standard for improved composability in DeFi.
Sky Vaults: Generating Dai Through Collateral
Vaults are smart contracts that allow users to lock collateral and generate Dai. They are non-custodial—users retain full control of their assets as long as collateralization ratios are maintained.
Step-by-Step Vault Interaction
- Create and Collateralize a Vault
Deposit supported assets (e.g., ETH, WBTC) via interfaces like Oasis Borrow or community-built dashboards. - Generate Dai
Borrow against your collateral. The amount depends on the asset’s liquidation ratio and debt ceiling. - Pay Down Debt + Stability Fee
Repay generated Dai plus accrued stability fees (paid only in Dai). - Withdraw Collateral
Once debt is cleared, retrieve your locked assets.
Each collateral type requires a separate Vault, enabling granular risk management.
Risk Management: Liquidations and Auctions
To ensure system solvency, undercollateralized Vaults are automatically liquidated.
Liquidation Ratio & Triggers
Each Vault type has a predefined Liquidation Ratio—the minimum collateral-to-debt threshold. If market movements cause this ratio to drop below the limit, liquidation begins.
For example:
- ETH-A Vault: 150% Liquidation Ratio
- If ETH price drops sharply and collateral falls below 1.5x the debt value → Vault becomes eligible for liquidation
Collateral Auction Process
When liquidated:
- The system initiates a Collateral Auction
- Auction Keepers bid Dai to purchase the collateral
- If obligations are covered, a Reverse Collateral Auction returns excess collateral to the owner
- Proceeds go to the Sky Protocol Buffer, covering debt and penalties
If auction proceeds fall short:
- The deficit triggers a Debt Auction, minting MKR to raise Dai
- Surplus funds beyond buffer limits trigger Surplus Auctions, burning MKR to reduce supply
This closed-loop mechanism protects protocol integrity during volatility.
RWA Vaults: Bridging Traditional Finance and DeFi
Sky pioneered the integration of Real World Assets (RWAs) into DeFi—tokenizing off-chain assets like bonds, loans, and real estate to serve as collateral.
Why RWAs Matter
RWAs bring:
- Lower volatility compared to crypto
- Diversified yield sources
- Institutional-grade income streams
- Enhanced capital efficiency
However, they require legal enforceability, third-party custodianship, and off-chain valuation processes.
Technical Structure of RWA Vaults
Each RWA vault consists of three core components:
- RWA Urn – The vault itself, governed by off-chain legal agreements
- RWA Token – Non-transferable token representing the underlying asset
- RWA Oracle – Controlled by governance; stores pricing data and legal documentation (e.g., IPFS hashes)
Optional helper modules include:
- Input/Output Conduits: For stablecoin swaps or third-party authorizations
- RWA Jar: Collects variable interest fees for accounting consistency
RWA Liquidation: A Two-Stage Off-Chain Process
Unlike instant crypto liquidations, RWA liquidations occur manually over weeks or months.
- Soft Liquidation
Triggered when covenants are breached; allows grace period for remediation. - Hard Liquidation
Initiated if recovery fails; debt is written off against the Surplus Buffer. If insufficient funds exist, MKR is minted via Flop auctions to recapitalize.
Despite slower resolution times, this framework enables safe exposure to high-yield traditional assets.
Governance in the Sky Ecosystem
MKR token holders govern all aspects of the protocol through decentralized voting.
Key Governance Mechanisms
- Executive Voting: Approves changes to system parameters
- Governance Polling: Gauges community sentiment pre-vote
- Proposal Contracts: Immutable smart contracts that execute approved changes
- Governance Security Module (GSM): Delays execution up to 24 hours for emergency review
MKR also acts as a recapitalization tool—new tokens are minted during debt crises to stabilize the system, aligning incentives for responsible governance.
Risk Parameters Controlled by Governance
Each Vault type has unique risk settings voted on by MKR holders:
| Parameter | Purpose |
|---|---|
| Debt Ceiling | Caps total borrowable Dai per collateral type |
| Stability Fee | Incentivizes timely repayment |
| Liquidation Ratio | Sets minimum collateral threshold |
| Liquidation Penalty | Discourages undercollateralization |
| Auction Durations | Controls timing of liquidation events |
These parameters adapt to market conditions, ensuring long-term resilience.
Price Stability & Emergency Protocols
Target Price & DSR Adjustments
Dai targets $1 USD. When market price deviates:
- Below $1 → Increase Dai Savings Rate (DSR) to boost demand
- Above $1 → Decrease DSR to reduce demand
Eventually, an Instant Access Module will allow rapid adjustments without full governance cycles.
Emergency Shutdown: Last Resort Protection
Triggered by MKR vote or ESM deposit, Shutdown has three phases:
- Freeze all Vault activity
- Complete outstanding Collateral Auctions
- Allow Dai holders to claim proportional collateral at Target Price
Though rare, this mechanism guarantees user exit rights during systemic threats.
Frequently Asked Questions (FAQ)
Q: What is the difference between Dai and USDS?
A: Both are USD-pegged stablecoins on Sky. Dai focuses on decentralization; USDS adds upgradeability and potential compliance features like freeze capability—only activatable via governance.
Q: Can anyone create an RWA Vault?
A: No. Only Sky Governance can deploy RWA vaults, which are managed by approved counterparties under legal agreements.
Q: How does the Dai Savings Rate work?
A: Users lock Dai into the DSR contract and earn interest automatically. Rates are adjusted by governance to maintain price stability.
Q: What happens if my Vault gets liquidated?
A: Your collateral is auctioned off. You may recover leftover assets after debt and penalties are paid—but could lose value if auctions underperform.
Q: Is there a minimum amount needed to use the DSR?
A: No. Any amount of Dai can be deposited into the DSR contract with no minimum requirement.
Q: How secure is the Sky Protocol?
A: It employs formal verification, third-party audits, bug bounties, and layered oracle security (OSM). While no system is immune to risk, Sky’s defense-in-depth approach sets industry standards.
The Future of Sky: Stars and the Allocation System
Post-rebranding, autonomous projects called Stars will drive RWA expansion under a new Allocation System. This framework enables efficient capital deployment into tokenized real-world assets while adhering to Sky’s risk controls.
Stars will:
- Operate independently but under governance oversight
- Access favorable borrowing rates from the protocol
- Inject liquidity into DeFi and RWA markets
- Promote ecosystem growth through diversified yield strategies
This evolution positions Sky as a hybrid finance leader—merging on-chain innovation with off-chain value.
External Actors Ensuring System Integrity
Three key roles support protocol operations:
- Keepers: Automated bots that maintain Dai’s peg through arbitrage
- Oracles: Provide price feeds via decentralized nodes; protected by OSM delay
- Emergency Oracles: Can freeze compromised feeds or trigger Shutdown
Community contributors also play vital roles in documentation, development, and education.
Final Thoughts
The Sky Protocol represents a landmark achievement in decentralized finance—offering stable, transparent, and globally accessible monetary tools. With dual stablecoins (Dai and USDS), advanced risk controls, RWA integration, and community-driven governance, Sky continues to evolve beyond crypto-native boundaries toward mainstream financial relevance.
As DeFi matures, Sky’s blend of innovation, security, and adaptability makes it a cornerstone of the open economy.
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