Architecture

The stacks-node has its own minimal set of http endpoints referred to as RPC endpoints

• The stacks-blockchain-api allows clients to access RPC endpoints by proxying requests to a load-balanced pool of stacks-nodes.
• For more details on RPC endpoints, see: RPC Endpoints Documentation
• Common RPC endpoints include:
  • POST /v2/transactions - Broadcast a transaction.
  • GET /v2/pox - Retrieve current Proof of Transfer (PoX) relevant information.
  • POST /v2/contracts/call-read/<contract>/<function> - Evaluate and return the result of calling a Clarity function.
  • POST /v2/fees/transaction - Evaluate a given transaction and provide transaction fee estimation data.
  • GET /v2/accounts/<address> - Fetch the current nonce required for creating transactions.

The stacks-blockchain-api implements additional endpoints that provide data unavailable directly from stacks-nodes due to various constraints.

• The stacks-node may not persist certain data or may not serve it efficiently to many clients. For instance, while it can return the current STX balance of an account, it cannot provide a history of account transactions.
• The API implements the Rosetta specification by Coinbase, an open standard designed to simplify blockchain deployment and interaction. More information can be found at: Rosetta API
• The API includes support for the Blockchain Naming System (BNS) endpoints. Details are available at: BNS Documentation
• For Express.js routes, see the directory: /src/api/routes

The API creates an "event observer" http server which listens for events from a stacks-node "event emitter"

• Events are HTTP POST requests containing:
  • Blocks
  • Transactions
  • Byproducts of executed transactions such as:
    • Asset transfers
    • Smart-contract log data
    • Execution cost data
• The API processes and stores these events as relational data in PostgreSQL.
• For the "event observer" code, see: /src/event-stream.

All http endpoints and responses are defined in OpenAPI and JSON Schema.

• See /docs/openapi.yaml
• Used to auto-generate the docs at https://hirosystems.github.io/stacks-blockchain-api/
• JSON Schemas are converted into TypeScript interfaces, which are used internally by the db controller module to transform SQL query results into the correct object shapes.
• OpenAPI and JSON Schemas are also used to generate a standalone @stacks/blockchain-api-client. The easiest/quickest way to develop in this repo is using the VS Code debugger. It uses docker-compose to setup a stacks-node and Postgres instance.

Alternatively, you can run npm run dev:integrated which does the same thing but without a debugger.