Throttle Requests with Flask-Limiter
Apply per-route and global rate limits.
Throttle Requests with Flask-Limiter is a free Flask Academy lesson on CoddyKit — lesson 1 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Flask Academy learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Why Throttle At All
Without limits, one client can flood your API and starve everyone else. Rate limiting caps how often a caller may hit your routes.
Meet Flask-Limiter
The go-to tool is the Flask-Limiter extension. It watches incoming requests and rejects callers who go over their allowance.
Install It
You add it like any other extension with pip. One package gives you decorators and config for limiting traffic.
pip install Flask-LimiterIdentify the Caller
A limiter needs a key to count by. The usual choice is the client IP via the built-in get_remote_address helper.
from flask_limiter.util import get_remote_addressCreate the Limiter
You build a Limiter and bind it to your app. The key function decides who each request counts against.
limiter = Limiter(get_remote_address, app=app)Set a Default Limit
A default_limits list applies one cap to every route at once. It is your safety net for the whole app.
limiter = Limiter(get_remote_address, app=app,
default_limits=["200 per day", "50 per hour"])Per-Route Limits
Tighten a single endpoint with the @limiter.limit decorator. This route gets its own stricter rule.
@app.route("/login")
@limiter.limit("5 per minute")
def login():
...Reading the Limit String
The string reads like plain English. 5 per minute means a caller may hit that route five times each minute.
"5 per minute"What 429 Means
When a caller exceeds the cap, Flask-Limiter returns 429 Too Many Requests. It is the polite way to say slow down.
Exempt a Route
Some endpoints, like a health check, should never be throttled. Mark them with @limiter.exempt to skip all limits.
@app.route("/health")
@limiter.exempt
def health():
return "ok"Use a Shared Backend
In production you run many app processes, so counts must live in a shared storage_uri like Redis, not memory.
Limiter(get_remote_address, app=app,
storage_uri="redis://localhost:6379")Quick Check
Pick the status a throttled client receives.
Recap
You added Flask-Limiter, keyed limits by IP, set default and per-route caps, exempted health checks, and learned the 429 reply. Great job!
Frequently asked questions
Is the “Throttle Requests with Flask-Limiter” lesson free?
Yes — the full text of “Throttle Requests with Flask-Limiter” is free to read here on the web, and the Flask Academy course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Flask Academy course, upgrade to CoddyKit PRO.
What will I learn in “Throttle Requests with Flask-Limiter”?
Apply per-route and global rate limits. You practise Flask Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Flask Academy?
No prior experience is required. Flask Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Throttle Requests with Flask-Limiter” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Flask Academy lesson?
Yes. Every Flask Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Throttle Requests with Flask-Limiter
- Configure CORS for Browser Clients
- Security Headers and HTTPS
- Validate Input to Stop Injection