Does FastAPI Work With Playwright?
FastAPI and Playwright work together seamlessly for building and testing modern web applications, with Playwright testing your FastAPI backend endpoints and frontend integrations.
Quick Facts
How FastAPI Works With Playwright
FastAPI and Playwright serve complementary roles in the modern web stack rather than direct integration. FastAPI handles your backend API logic with automatic OpenAPI documentation, while Playwright executes end-to-end tests against your running FastAPI application. You typically run FastAPI as a server process and point Playwright tests at its endpoints (localhost:8000). This architecture is ideal for testing full user workflows—Playwright can navigate a frontend application that consumes your FastAPI endpoints, verifying both UI behavior and API responses. The developer experience is smooth: start your FastAPI app with `uvicorn`, write Playwright tests in Python or JavaScript, and validate the entire stack. Most teams use pytest fixtures to manage FastAPI TestClient for unit/integration tests and Playwright for true end-to-end scenarios. The only architectural consideration is ensuring your test environment can handle concurrent requests and database state management across multiple test runs.
Best Use Cases
Quick Setup
pip install fastapi uvicorn playwright pytest pytest-asyncio# app.py
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
app = FastAPI()
app.add_middleware(CORSMiddleware, allow_origins=["*"])
@app.get("/api/hello")
async def hello(name: str = "World"):
return {"message": f"Hello {name}"}
# test_app.py
import pytest
from playwright.async_api import async_playwright
@pytest.mark.asyncio
async def test_hello_endpoint():
async with async_playwright() as p:
browser = await p.chromium.launch()
page = await browser.new_page()
# Test the endpoint directly
response = await page.goto("http://localhost:8000/api/hello?name=Alice")
text = await page.text_content("body")
assert "Hello Alice" in text
await browser.close()Known Issues & Gotchas
CORS errors when Playwright frontend tests hit FastAPI from different origins
Fix: Configure FastAPI's CORSMiddleware with appropriate origins, or use proxy settings in Playwright context
Test database state pollution when multiple Playwright tests run concurrently
Fix: Use database transactions rolled back after each test or separate test databases per test worker
Timing issues when Playwright tries to interact with pages before FastAPI endpoints respond
Fix: Use Playwright's built-in wait mechanisms (waitForLoadState, waitForSelector) instead of fixed sleeps
Alternatives
- •Django + Selenium: More mature combination for traditional server-rendered applications
- •Next.js + Playwright: Integrated JavaScript solution for full-stack applications
- •Flask + Cypress: Lighter alternative for smaller Python projects
Resources
Related Compatibility Guides
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