Custom Backend

Introduction to Custom Backend

A custom backend in OpenBB Terminal Pro allows users to integrate their own data sources into the platform using an API. This enables the creation of personalized widgets, dashboards, and templates that can display your data in many different ways. The custom backend allows users to take full advantage of the OpenBB Copilot and our interface.

Design and implement your API

You can build your API using any language and framework of your choice. The only requirements are that there must be endpoints returning data in JSON format, and that CORS is supported for OpenBB domains.

note

Guidelines for JSON Format in Tables:

• The JSON data for tables should be in a flat structure, meaning that there should be no nested dictionaries or arrays within the individual objects unless you specify the dataKey in your widgets.json file.
• Each object should contain key-value pairs where the values are simple data types (e.g., strings, numbers, booleans).
• Avoid nesting other objects or arrays inside any of the values.

The JSON should resemble the following structure:

Example JSON

[
      {
        "ticker": "AAPL",
        "name": "Apple Inc.",
        "price": 150.5,
        "marketCap": 2500000000,
        "change": 1.25
      },
      {
        "ticker": "GOOGL",
        "name": "Alphabet Inc.",
        "price": 2800.75,
        "marketCap": 1900000000,
        "change": -0.75
      },
      {
        "ticker": "MSFT",
        "name": "Microsoft Corporation",
        "price": 300.25,
        "marketCap": 220000000,
        "change": 0.98
      }
]

Creating your own custom backend

To integrate your own backend with OpenBB, follow these steps:

1. Develop an API to return JSON data: Use any language to create an API that returns JSON data. We recommend Python with FastAPI. Ensure CORS is enabled for OpenBB domains.

Click to view FastAPI setup

import json
from pathlib import Path
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse

app = FastAPI()

# Define allowed origins for CORS
origins = [
    "https://pro.openbb.co",
    "https://excel.openbb.co"
]

# Add CORS middleware to the app
app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

ROOT_PATH = Path(__file__).parent.resolve()

@app.get("/")
def read_root():
    """Root endpoint providing basic information."""
    return {"Info": "Full example for OpenBB Custom Backend"}

@app.get("/widgets.json")
def get_widgets():
    """Serve the widgets configuration file for the OpenBB Custom Backend."""
    return JSONResponse(
        content=json.load((ROOT_PATH / "widgets.json").open())
    )

2. Create widgets.json file: This file is your main configuration and defines widget properties such as name, description, category, endpoint, type of widget, and other information. Each widget will be defined in this file. To view a sample widgets.json file and learn more about what you can do check out the widgets.json docs.

An example structure in your backend might look like below.

  backend/
  ├── main.py
  └── widgets.json
  └── templates.json (optional)

3. Build Endpoints: Develop endpoints in main.py for each widget defined in widgets.json.

4. Create Templates (optional): You can use this to create a layout for your widgets to be displayed in OpenBB Workspace. This lets users easily add widgets in a predefined layout. To view a sample templates.json file and learn more about what you can do check out the templates.json docs.

5. Connect to your API: Use the OpenBB Terminal Pro interface to connect your API. Input your main endpoint, and the system will read the /widgets.json and /templates.json endpoints to add them to OpenBB.

Examples

Our team has created several examples that you can use to quickly get started with Python and FastAPI. For more information, check out this open source repository.

Still have questions? Check out the FAQs section.