Helios Finance
  • Introduction
    • Problem - Solution
    • How Helios Differs from Other Protocols
    • Summary of Capabilities
  • Quickstart
    • Installing Leather Wallet
    • Add MIDL regtest on Leather
    • Get test tokens from faucet
    • Experience the new BTC Defi
  • Architecture
    • Overview
      • Helios & MIDL Architecture Overview
      • MIDL Validator Network (DPoS Consensus Layer)
      • Threshold Signature Scheme
      • Lending Logic Layer by Helios
      • Roles and Responsibilities Summary
    • Bitcoin-Native Smart Contracts
    • Bitcoin Settlement Flow and One-Step Transactions
    • Bitcoin Settlement & Finality
  • Core Concepts
    • Overview
    • BTC-Native Liquidity, Expanded Asset Support
      • Interest Mechanics
      • Supported Assets
    • Partial Collateral Swap (Flexible Position Management)
  • Risk Framework
    • Overview
    • Adaptive Risk Optimization (Mempool- & Volatility-Aware LTVs)
      • More on Adaptive Risk Engine
    • Liquidation Mechanics
  • Capital Efficiency and Use Cases
    • Overview
    • Delta-Neutral Yield Strategies
    • Enhanced Yield for Bitcoin Holders
    • Arbitrage and Market Efficiency
    • Tax-Optimized Borrowing
  • Institutional Compliance and Security
    • Overview
    • KYC-Ready Architecture and Permissioned Pools
      • More on Dual-Layer Market
    • AML, Monitoring, and Auditability
    • Regulatory Alignment (MiCA, BIS/IOSCO, etc.)
  • For Developers
    • Overview
    • Interest Rate Model
    • Supply & Borrow Interest
    • Functions
      • Common Functions
      • Supply & Withdraw
      • Borrow & Repay & Liquidate
      • Flashloan
    • SDK Release Plan
    • Smart Contract Interface via MIDL (EVM on Bitcoin)
    • Transaction Fees
  • Oracles and Price Feeds
  • Running a Liquidator or Integration with Exchanges
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  1. Architecture

Bitcoin-Native Smart Contracts

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Last updated 29 days ago

At the heart of Helios is the MIDL execution layer, which provides a smart contract platform native to Bitcoin. MIDL (Modular Integrated Decentralized Ledger) functions as an EVM-compatible layer operating on top of Bitcoin’s blockchain. It’s not a separate alt-chain, sidechain, or Bitcoin L2 that needs bridging; instead, it piggybacks on Bitcoin for ordering and finality. Specifically, each batch of Helios contract executions produces a cryptographic commitment (e.g., a Merkle root of the new state) that is embedded in an actual Bitcoin transaction. This gives a tamper-resistant, verifiable log of Helios’s smart contract state changes on Bitcoin – effectively extending Bitcoin with Ethereum-like computation without altering Bitcoin’s consensus rules.

How it works

Users initiate Helios actions by sending ordinary Bitcoin transactions with encoded data that invoke MIDL smart contracts. For example, to deposit BTC and take a loan, a user sends BTC to a TSS vault (managed by the MIDL validators) with an attached instruction. The validators detect this, execute the corresponding lending logic in the EVM layer, and then commit the outcome on-chain in the next Bitcoin block. Because MIDL is EVM-compatible, Helios’s contract logic is written similarly to Ethereum smart contracts (Solidity), making it familiar to developers. The execution layer’s modularity also means Helios’s core logic could be portable to other Bitcoin execution layers or sidechains if needed, ensuring flexibility and upgradability. All contract events (deposits, loans, interest accrual, etc.) ultimately settle in Bitcoin transactions, so the source of truth is always the Bitcoin ledger.

This design provides Ethereum-level functionality with Bitcoin-level security. There are no bridges or secondary tokens – raw BTC itself is used for fees and collateral, preserving the “nativity” which is crucial for trustless operation on Bitcoin. By using Bitcoin’s blockchain for finality, Helios inherits Bitcoin’s robustness (e.g., enormous hash power security) while introducing programmability through MIDL. In essence, MIDL acts as an execution sandbox whose state is anchored to Bitcoin blocks, enabling complex DeFi operations to run natively for the first time on Bitcoin.

For more information, please refer to MIDL's Gitbook, especially the validator section().

https://midl.gitbook.io/midl/midl-overview/validators