# JSON-RPC

[RPC](https://en.wikipedia.org/wiki/Remote_procedure_call) is a [request–response](https://en.wikipedia.org/wiki/Request%E2%80%93response) concept when a computer program causes a procedure to execute in a different [address space](https://en.wikipedia.org/wiki/Address_space) (commonly on another computer on a shared network). 

In our case, we can say that RPC is a way for an external program—for example, a browser or front-end application—to communicate with the humanode peer to explore current network state and submit extrinsics.

Humanode provides several [substrate based RPCs](https://docs.substrate.io/build/custom-rpc/) to communicate with a node including [default  list of RPCs](https://polkadot.js.org/docs/substrate/rpc/) that substrate comes with.

We would like to introduce more common and useful RPCs including custom bioauth related ones.

## Chain state RPCs

Storage related RPCs allows you to explore current chain state based on provided `module` and `method`. It's done via `api.query.<module>.<method>` call.

The full list of available storage RPCs you can find [here](https://polkadot.js.org/docs/substrate/storage).

## Extrinsics RPCs

Extrinsics for particular `module` and `method` can be submitted using `api.tx.module.method` call.

The full list of available extrinsics RPCs you can find [here](https://polkadot.js.org/docs/substrate/extrinsics).

## Bioauth RPCs

Humanode team has developed bioauth related [custom RPCs](https://docs.substrate.io/build/custom-rpc/#rpc-extension-builder) with the following functionalities:

Authentication based on provided liveness data

* **interface**: `api.rpc.bioauth.authenticate`
* **jsonrpc**: `bioauth_authenticate`

Enrollment based provided liveness data.

* **interface**: `api.rpc.bioauth.enroll`
* **jsonrpc**: `bioauth_enroll`

Getting the current bioauth status.

* **interface**: `api.rpc.bioauth.status`
* **jsonrpc**: `bioauth_status`

Getting a FaceTec Session Token.

* **interface**: `api.rpc.bioauth.getFacetecSessionToken`
* **jsonrpc**: `bioauth_getFacetecSessionToken`

Getting the configuration required for the Device SDK.

* **interface**: `api.rpc.bioauth.getFacetecDeviceSdkParams`
* **jsonrpc**: `bioauth_getFacetecDeviceSdkParams`


---

# Agent Instructions: Querying This Documentation

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

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://gitbook.humanode.io/docs/node/json-rpc.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.