Rate limiting and authentication in LangChain - Mini Project: Build & Apply

Rate limiting and authentication with LangChain

📖 Scenario: You are building a simple chatbot using LangChain that connects to an API. To keep the API safe, you want to add authentication and limit how many times the chatbot can call the API in a short time.

🎯 Goal: Build a LangChain chatbot that uses an API key for authentication and limits the number of API calls to 3 per minute.

📋 What You'll Learn

Create a variable called api_key with the exact value '12345-ABCDE'

Create a variable called max_calls_per_minute and set it to 3

Use a RateLimiter from langchain to limit calls to max_calls_per_minute

Add the api_key to the LangChain API client configuration

💡 Why This Matters

🌍 Real World

APIs often require authentication to keep data safe and rate limiting to prevent overload. This project shows how to do both simply with LangChain.

💼 Career

Understanding API authentication and rate limiting is important for building reliable and secure applications that use external services.

1

DATA SETUP: Create the API key variable

Create a variable called api_key and set it exactly to the string '12345-ABCDE'.

LangChain

# Your code here

Need a hint?

Think of api_key as your secret password to use the API.

2

CONFIGURATION: Set the rate limit variable

Create a variable called max_calls_per_minute and set it to the number 3.

LangChain

api_key = '12345-ABCDE'
# Your code here

Need a hint?

This number controls how many times you can call the API every minute.

3

CORE LOGIC: Use RateLimiter to limit API calls

Import RateLimiter from langchain and create a rate_limiter object that limits calls to max_calls_per_minute per minute.

LangChain

api_key = '12345-ABCDE'
max_calls_per_minute = 3
# Your code here

Need a hint?

RateLimiter helps you control how often your code can call the API.

4

COMPLETION: Configure LangChain client with API key and rate limiter

Create a LangChain API client called client using api_key for authentication and apply rate_limiter to limit calls.

LangChain

from langchain import RateLimiter

api_key = '12345-ABCDE'
max_calls_per_minute = 3

rate_limiter = RateLimiter(max_calls=max_calls_per_minute, period=60)
# Your code here

Need a hint?

This sets up the chatbot client with your secret key and the rate limit to keep API calls safe.