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Blueprints is an ecosystem of classes of tokens, each of the instances expressing a position. Examples of tokens include:

• NativeToken<18> – can be minted by depositing the chain's native token (e.g. ETH) and burned to withdraw it,
• ERC20Wrapper<0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2, 18> – can be minted by depositing an ERC20 token with given address and burned to withdraw it,
• ComposablePrediction<10 NativeToken<18>, [(MultisigOracle<[0xD28718f6Ca7398897417eD3aBbD8C2522776E1bf, 0x663056E2C695Be0d593271513C6a0794Bc7E6E6F, 0xd162c1Ca3357E4F2624BA0cdC57A8e4471502189], 2, 0xe633c357cfe0000425d02d5fca7f16aaa0823f02afe77b9126cc512d2080e661>, 1, 0)]> – can be exchanged for 10 NativeToken<18> if at least 2 out of 3 signers sign that the feed with id e633c357cfe0000425d02d5fca7f16aaa0823f02afe77b9126cc512d2080e661 resolves to an integer between 1 and infinity (anything but zero),
• WithMetadata<1 NativeToken<18>, {"user_comment":"I know I'm overexposed but the price is down right now"}> – wraps a position together with arbitrary bytes without changing the underlying token id.

Although positions expressed by these tokens are vastly different, all of them share a common interface.

As seen in the latter example, the tokens are composable – one position can be an argument of another. This allows infinitely intricate positions to be created from simple primitives.

Benefits of using Blueprints

• Time spent on development. The vast majority of the products can be built using existing primitives, there's no need to develop any smart contracts.
• Money saved on audits. Auditing smart contracts can be very expensive and time-consuming. Blueprints fix that.
• Security improvement. Blueprints are extremely simple and concise – so much that mistakes are difficult to make. You don't have to risk using novel smart contracts.
• User verifiability. Users can verify their positions instead of trusting new contracts for every new app they're using.
• Unified liquidity. Many products use the same positions. On Blueprints, they all "talk in the same language", which means that it's possible to seamlessly plug in to the ecosystem's liquidity. One user's counterparty can be a user of a different product.
• Extensibility. To add your own primitive, you only need to write the code that describes the position. Everything else (managing balances, transfers, approvals, etc.) is already handled.

Blueprints

NativeToken, ERC20Wrapper, ComposablePrediction are examples of Blueprints. Each of them is implemented in a separate smart contract. Anyone can create and deploy their own Blueprint.

Each smart contract manages their own token space. Tokens minted by a Blueprint have a 256-bit internal token id. The external token id is calculated by hashing the smart contract's address and the internal token id. This assures that, for example, the NativeToken Blueprint cannot mint ERC20Wrapper tokens.

Blueprint Manager

Blueprint Manager is a smart contract which keeps track of balances. Each address is split into $2^{256}$ subaccounts which is oftentimes helpful. Blueprint Manager also implements flash accounting – the ability to spend tokens one will receive later in the same transaction.

Oracles

An oracle feed is defined by the oracle address and a 256-bit feed id. The interpretation of the feed id is left to the operator of the oracle. A feed resolves to a 256-bit unsigned integer.

Oracles shouldn't return different readings for the same feed id, but technically there's nothing preventing them from doing so. If consistent readings are desired, you can wrap an oracle in a ConstantOracle.