JavaScript SDK Integration

LimitYourAPI JavaScript SDK for Node.js and edge runtimes.

JavaScript SDK Integration Guide

Install the official LimitYourAPI JavaScript SDK to restrict client request rates in Node.js, Express, and modern browser environments. For type-safe applications with full interface definitions, please see the [TypeScript SDK](/sdk/typescript).

1. Installation

`bash

npm install limityourapi

`

2. Simple Usage

Initialize the client and check rate limits inline:

`javascript

import { LimitYourAPIClient } from 'limityourapi';

const limiter = new LimitYourAPIClient({

apiKey: process.env.LIMIT_YOUR_API_KEY

});

const response = await limiter.check({

key: 'user_12345',

route: '/api/resource',

cost: 1

});

if (!response.allowed) {

console.log(Rate limit exceeded! Retry after ${response.retryAfter}s);

}

`

3. Express Middleware Example

Implement rate limiting globally or per-route inside Express:

`javascript

import express from 'express';

import { LimitYourAPIClient } from 'limityourapi';

const app = express();

const limiter = new LimitYourAPIClient({

apiKey: process.env.LIMIT_YOUR_API_KEY

});

const rateLimitMiddleware = async (req, res, next) => {

try {

const key = req.ip;

const decision = await limiter.check({ key, route: req.path });

res.setHeader('X-RateLimit-Limit', decision.limit);

res.setHeader('X-RateLimit-Remaining', decision.remaining);

res.setHeader('X-RateLimit-Reset', decision.reset);

if (!decision.allowed) {

res.setHeader('Retry-After', decision.retryAfter);

return res.status(429).json({ error: 'Too Many Requests', retryAfter: decision.retryAfter });

}

next();

} catch (error) {

console.error('Rate limit error:', error);

next();

}

};

app.use('/api/', rateLimitMiddleware);

`

4. Production Checklist

• Always pass a secure API key (rl_...) loaded via environment variables.
• Enable failOpen: true in production to prevent caching layer outages from dropping client requests.
• Configure socket timeouts (timeout: 1000) to maintain low latency bounds.
• Set custom key identifiers to trace limits by authenticated User ID rather than shared client IPs.