> For the complete documentation index, see [llms.txt](https://docs.stacks.co/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.stacks.co/reference/api/stacks-blockchain-api/architecture.md).

# Architecture

How the Stacks Blockchain API fits between a Stacks node and your app.

![Stacks Blockchain API architecture](https://1374237750-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGVj1Z9vMuEOMe7oH7Wnq%2Fuploads%2Fgit-blob-a9452d780cb07eb8fef43f1d06d4dadadd93937c%2Fstacks-blockchain-api-architecture.svg?alt=media)

Hiro builds and maintains the Stacks Blockchain API. Hiro's documentation is the source of truth for its design, endpoints and deployment. For the full architecture, see [Stacks Blockchain API architecture](https://docs.hiro.so/apis/stacks-blockchain-api/architecture) on docs.hiro.so and the [source repository](https://github.com/hirosystems/stacks-blockchain-api).

## How it works

* **Ingests events from a Stacks node.** A Stacks node sends blocks, transactions and their byproducts (asset transfers, contract events, execution costs) to the API's event observer.
* **Stores them in PostgreSQL.** The API indexes that data so it can answer questions a node cannot serve efficiently, such as an account's transaction history.
* **Serves indexed data under `/extended`.** These are the API's own endpoints.
* **Proxies node RPC under `/v2`.** Requests to `/v2` paths go straight to the Stacks node's RPC endpoints. For those endpoints, see the [Stacks Node RPC reference](/reference/api/stacks-node-rpc.md).


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.stacks.co/reference/api/stacks-blockchain-api/architecture.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.