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Version: v5

Quick start — Developer

Any FastAPI app or APIRouter registered under the openbb_core_extension entry-point group becomes an OpenBB extension. Its routes are served by the OpenBB REST API and generated as methods on obb. This page registers a one-route router and calls it both ways.

1. Install openbb-core​

pip install openbb-core

FastAPI and Uvicorn are installed with it.

2. Write the router​

Create a project directory with an empty my_extension/__init__.py and this my_extension/app.py:

from fastapi import APIRouter
from pydantic import BaseModel


class GreetResponse(BaseModel):
    message: str


router = APIRouter()


@router.get("/greet")
def greet(name: str = "world") -> GreetResponse:
    """Return a greeting."""
    return GreetResponse(message=f"hello, {name}")

This is an ordinary FastAPI router with no OpenBB imports.

3. Register the entry point​

pyproject.toml in the project directory:

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

[project]
name = "openbb-my-app"
version = "0.1.0"
requires-python = ">=3.10"
dependencies = ["openbb-core"]

[project.entry-points."openbb_core_extension"]
my_app = "my_extension.app:router"

[tool.hatch.build.targets.wheel]
packages = ["my_extension"]

The entry-point name, my_app, becomes the namespace on obb and the path segment in the REST API. The value must point to an already-created FastAPI or APIRouter instance; factory functions are not called.

4. Install the package​

From the project directory:

pip install -e .

5. Build the Python Interface​

openbb-build

This generates the obb.my_app methods. Importing openbb also rebuilds on its own when it detects a newly installed extension; Packaging and static assets explains when each applies.

6. Call it from Python​

from openbb import obb

obb.my_app.greet(name="analyst")
GreetResponse(message='hello, analyst')

The Python Interface returns whatever the route returns. OpenBB does not wrap it in an OBBject, so the to_dataframe() family of methods is not available on this result. To get them, annotate the route's return type as OBBject[...] and return OBBject(results=...); see The OBBject envelope.

7. Call it over REST​

Start the API with Uvicorn, which serves commands under /api/v1:

uvicorn openbb_core.api.rest_api:app --host 127.0.0.1 --port 8000

In another terminal:

curl "http://127.0.0.1:8000/api/v1/my_app/greet?name=analyst"
{"message":"hello, analyst"}

The openbb-api launcher from openbb-platform-api serves the same routes on port 6900 by default and adds OpenBB Workspace support; see Quick start (REST API).

If openbb-build fails, set OPENBB_DEBUG_MODE=true and run it again for the full error. From FastAPI covers how dependencies, streaming responses, and other FastAPI features behave in the Python Interface, and the Developer section covers building providers and native OpenBB routers.

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