1.0.2 • Public • Published


Shadows is a decentralized synthetic asset issuance protocol built on Substrate. The value of these synthetic assets is underpinned by DOWS, and as long as DOWS is locked in a smart contract, synthetic assets can be issued.

Unique debt pool design mechanism. Trading of synthetic assets is essentially a transfer between debts. Smart contracts automatically execute the conversion of a synthetic asset to another synthetic asset without an order book, without counterparties, and without the problems of liquidity and trading slippage.


Usage and requirements

For tests (in javascript)

Install the dependencies for the project using npm

$ npm i

To run the tests:

$ npm test


  • ExchangeRates.sol: A key value store (bytes4 -> uint) of currency exchange rates, all priced in USD. Understands the concept of whether a rate is stale (as in hasn't been updated frequently enough), and only allows a single annointed oracle address to do price updates.
  • ExternStateToken.sol: The concept of an ERC20 token which stores its allowances and balances outside of the contract for upgradability.
  • FeePool.sol: Understands fee information for Shadows. As users transact, their fees are kept in 0xfeefeefee... and stored in xUSDs. Allows users to claim fees they're entitled to.
  • Shadows.sol: Has a list of Synths and understands issuance data for users to be able to mint and burn Synths.
  • ShadowsEscrow.sol: During the crowdsale, users were asked to escrow their Havvens to insulate against price shocks on the token. Users are able to unlock their DOWS on a vesting schedule.
  • Depot.sol: Allows users to exchange ETH for xUSD and DOWS (has not yet been updated for multicurrency).
  • LimitedSetup.sol: Some contracts have actions that should only be able to be performed during a specific limited setup period. After this period elapses, any functions using the onlyDuringSetup modifier should no longer be callable.
  • Migrations.sol: Truffle's migrations contract.
  • Synth.sol: Synth token contract which remits fees on transfers, and directs the Shadows contract to do exchanges when appropriate.
  • SynthAirdropper.sol: Used to optimise gas during our initial airdrop of Synth.
  • Owned.sol: Allows us to leverage the concept of a contract owner that is specially priviledged and can perform certain actions.
  • Pausable.sol: Implements the concept of a pause button on a contract. Methods that should be paused use a particular modifier.
  • Proxy.sol: Our proxy contracts which forward all calls they receive to their target. Events are always emitted at the proxy, not within the target, even if you call the target directly.
  • Proxyable.sol: Implemented on a contract so it can be the target of a proxy contract.
  • SafeDecimalMath.sol: Safe math + decimal math. Using _dec on an operation makes it operate "on decimals" by either dividing out the extra UNIT after a multiplication, or multiplying it in before a division.
  • SelfDestructible.sol: Allows an owner of a contract to set a self destruct timer on it, then once the timer has expired, to kill the contract with selfdestruct.
  • State.sol: Implements the concept of an associated contract which can be changed by the owner.
  • TokenState.sol: Holds approval and balance information for tokens.

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npm i shadows-contract


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