diff --git a/.gitignore b/.gitignore
index 4befed3..274a208 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,27 @@
+# OS
 .DS_Store
 .idea
+.vscode
+
+# Python
+__pycache__/
+*.py[cod]
+*.egg-info/
+dist/
+.venv/
+.ruff_cache/
+
+# Secrets
+.env
+.env.*
+
+# Data & Models (large files, local only)
+data/
+weights/
+
+# Database
+*.db
+*.sqlite3
+
+# Tile cache
+tile_cache/
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000..dbe16c1
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,41 @@
+[project]
+name = "gps-denied-onboard"
+version = "0.1.0"
+description = "GPS-denied UAV geolocalization service"
+requires-python = ">=3.11"
+dependencies = [
+    "fastapi>=0.115",
+    "uvicorn[standard]>=0.34",
+    "pydantic>=2.0",
+    "pydantic-settings>=2.0",
+    "sqlalchemy>=2.0",
+    "alembic>=1.14",
+    "sse-starlette>=2.0",
+    "aiosqlite>=0.20",
+]
+
+[project.optional-dependencies]
+dev = [
+    "ruff>=0.9",
+    "pytest>=8.0",
+    "pytest-asyncio>=0.24",
+    "httpx>=0.28",
+]
+
+[build-system]
+requires = ["setuptools>=75"]
+build-backend = "setuptools.build_meta"
+
+[tool.setuptools.packages.find]
+where = ["src"]
+
+[tool.ruff]
+target-version = "py311"
+line-length = 100
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "W"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]
+asyncio_mode = "auto"
diff --git a/src/gps_denied/__init__.py b/src/gps_denied/__init__.py
new file mode 100644
index 0000000..5894694
--- /dev/null
+++ b/src/gps_denied/__init__.py
@@ -0,0 +1,3 @@
+"""GPS-Denied Onboard — UAV geolocalization service."""
+
+__version__ = "0.1.0"
diff --git a/src/gps_denied/__main__.py b/src/gps_denied/__main__.py
new file mode 100644
index 0000000..b619db8
--- /dev/null
+++ b/src/gps_denied/__main__.py
@@ -0,0 +1,16 @@
+"""Entry point: python -m gps_denied."""
+
+import uvicorn
+
+
+def main() -> None:
+    uvicorn.run(
+        "gps_denied.app:app",
+        host="127.0.0.1",
+        port=8000,
+        reload=True,
+    )
+
+
+if __name__ == "__main__":
+    main()
diff --git a/src/gps_denied/app.py b/src/gps_denied/app.py
new file mode 100644
index 0000000..fecd751
--- /dev/null
+++ b/src/gps_denied/app.py
@@ -0,0 +1,23 @@
+"""FastAPI application factory."""
+
+from fastapi import FastAPI
+
+from gps_denied import __version__
+
+
+def create_app() -> FastAPI:
+    """Create and configure the FastAPI application."""
+    application = FastAPI(
+        title="GPS-Denied Onboard",
+        version=__version__,
+        description="UAV geolocalization service for GPS-denied environments",
+    )
+
+    @application.get("/health")
+    async def health() -> dict:
+        return {"status": "ok"}
+
+    return application
+
+
+app = create_app()
diff --git a/tests/test_health.py b/tests/test_health.py
new file mode 100644
index 0000000..61524bf
--- /dev/null
+++ b/tests/test_health.py
@@ -0,0 +1,16 @@
+"""Tests for the health endpoint."""
+
+import pytest
+from httpx import ASGITransport, AsyncClient
+
+from gps_denied.app import app
+
+
+@pytest.mark.asyncio
+async def test_health_returns_ok():
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as client:
+        response = await client.get("/health")
+
+    assert response.status_code == 200
+    assert response.json() == {"status": "ok"}