Unified blockchain transfers API

Currently experimental and not stable

Attempt to provide unified API to cryptocurrencies from e-commerce and wallet perspective.

Key aspects:

• Native blockchain currencies and tokens unified and can be used without symbol table
• Currency transfers unified for native and other different tokens.
• Block and transaction view unified across blockchains
• Optional client-side private keys and signing process
• Stateless core services which can be implemented without indexing for any blockchain
• Optional services like balance lookups which may need indexing and storage
• Performant GRPC based protocol intended for internal or public internet usage

See protobuf definitions in 'proto' dir for grpc services and models

Inspired by Rosetta API

Core

Core functionality is what should be implemented by any blockchain to be compatible with this API otherwise it doesn't make sense.

• Block parsing and converting to universal structures.
• Constructing and broadcasting 'transfer' transactions
• Address generation

Core model

Chain ID

(chain-type)[:chain-network]

• chain-type - general approach is to get symbol from (https://github.com/satoshilabs/slips/blob/master/slip-0044.md)[SLIP-0044] filtering out non-native or cross-chain coins
• chain-network - instance of the network like mainnet, testnet, regtest, etc. mainnet is default and can be omitted

Unified Currency ID

Normalized form:

F:(ISO4217-3-symbol-currency-code) | C:chain-id[:address[:token-id]]

• All parts except address and token-id are uppercase. Empty trailing parts are eliminated.
• F or C - currency type. F - fiat, C - crypto
• chain-id - blockchain identifier
• address - contract address of the token
• token-id - token identifier within the token contract or id if blockchain supports custom tokens without contract

Parsing is bit more lenient:

• All parts except address and token-id are case-insensitive
• Empty parts can be included

Examples:

• F:USD - fiat currency
• C:ETH - native currency of ethereum blockchain (ETH itself)
• C:ETH::0x6b175474e89094c44da98b954eedeac495271d0f - DAI token on Ethereum blockchain
• C:ETH:MAINNET:0x6b175474e89094c44da98b954eedeac495271d0f: - same as above
• c:Eth:mainnet:0x6b175474e89094c44da98b954eedeac495271d0f: - same as above

Transfers

While most blockchains operate with blocks + transactions extracting actual money transfers delegated to client developer who need to extract native, contract based or other types of transfers from transaction data. This API provides unified view of transfers which is transfering owneship of some amount of some currency identified by Unified Currency ID from one account to another.

Simplified Transfer structure

• id - unique transfer id within the network, usually transaction hash + transfer index within tx
• from - source account
• to - destination account
• amount - uin256 amount + currency id

Services

• Network - information and status about connected blockchains
• Blocks - read access to blocks, transactions and transfers
• Construct - construct and broadcast transfers and transactions
• Balances - indexed access to balances of any address in any currency
• Currencies - currency introspection api
• Account Manager - delegate account/private keys management to external service

Build

Uses Earthly as build system.

Generate from protobufs:

earthly +generate

Build:

earthly +build

Build and push packages:

earthly +publish

Credits

• Rosetta API - inspiration and some ideas