Intro

Blueprints is a free and open-source on-chain framework for expressing customized financial positions, created by parametrizing existing primitives. Examples of tokens include:

• 1 NativeToken<18> – can be minted by depositing one native token (e.g. 1 ETH) and burned to withdraw it,
• 20 ERC20<0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2, 18> – can be minted by depositing 20 ERC20 tokens with the given address and burned to withdraw them,
• 0.05 ComposablePrediction<1 NativeToken<18>, [(MultisigOracle<[0xD28718f6Ca7398897417eD3aBbD8C2522776E1bf, 0x663056E2C695Be0d593271513C6a0794Bc7E6E6F, 0xd162c1Ca3357E4F2624BA0cdC57A8e4471502189], 2, keccak256({"market":"BTC","condition":"above 100000","time":"2027-01-01 00:00:00 UTC"})>, 1, 0)]> – can be exchanged for 0.05 NativeToken<18> if at least 2 out of 3 signers sign that the specified feed resolves to an integer between 1 and infinity (anything but zero),
• 10 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.

Testnet

The Blueprints team hosts a public testnet that can be used to test products built on Blueprints.

• Chain ID: 0x42504649 (the ASCII code points of BPFI are 0x42, 0x50, 0x46, and 0x49)
• RPC URL: https://testnet-rpc.blueprints.finance/
• Faucet: https://testnet-faucet.blueprints.finance/

Architecture overview

This section provides an overview of the Blueprints architecture. Consult the smart contracts' source code for details.

Blueprints

NativeToken, ERC20, and 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 its 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 ERC20 tokens.

Each Blueprint defines a set of valid actions that can be performed. In principle, each address should be able to perform the same actions. An action consists of 4 arrays of tokens.

• mint – tokens that are to be minted by the Blueprint and sent to the address performing the action,
• burn – tokens that are to be taken from the address performing the action and burned; these tokens must have been minted by the same Blueprint,
• give – tokens that are to be transferred from the Blueprint to the address performing the action; these tokens could have been minted by another Blueprint,
• take – tokens that are to be transferred from the address performing the action to the Blueprint; these tokens could have been minted by another Blueprint.

For example, the Basket Blueprint allows the following actions:

• take some tokens and mint a token which represents a basket of them,
• burn a token representing a basket of tokens and give those 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.