Node.js

In-Memory Rate Limiter for Express

Token bucket rate limiter middleware for Express with configurable window and max requests per IP.

Best for: API abuse prevention

#express#rate-limit

Async Error Handler Wrapper

Higher-order function that wraps async Express route handlers and forwards rejected promises to error middleware.

Best for: Express route error handling

#express#async

Environment Variable Validator

Validates required environment variables at startup and returns a typed config object or throws with missing keys.

Best for: App startup validation

#config#validation

File Upload with Multer

Configure Multer for disk storage with file type validation, size limits, and unique filenames for Express.

Best for: Profile avatar uploads

#express#upload

HTTP Client with Axios Interceptors

Pre-configured Axios instance with request/response interceptors for auth headers, logging, and retry logic.

Best for: Consuming third-party APIs

#axios#http

Redis Cache Get/Set Helper

Type-safe Redis cache wrapper with automatic JSON serialization, TTL support, and cache-aside pattern.

Best for: Database query caching

#redis#cache

Graceful Server Shutdown

Handle SIGTERM and SIGINT signals to drain connections, close database pools, and exit cleanly.

Best for: Production server deployment

#server#shutdown

Stream File Download

Express handler that streams a file to the client with proper headers, range support, and error handling.

Best for: Large file downloads

#stream#download

UUID and Nano ID Generator

Generate RFC-4122 v4 UUIDs and URL-safe nano IDs using the Node.js built-in crypto module with zero deps.

Best for: Database primary keys

#uuid#crypto

Prisma Find with Relations

Query related records using Prisma ORM include and select for efficient nested data loading.

Best for: Loading user profiles with posts

#prisma#orm

Bull Queue Job Producer & Consumer

Create a job queue with Bull for background processing with retries and concurrency control.

Best for: Email sending queue

#queue#bull

Express Zod Request Validation

Validate Express request body, params, and query with Zod schemas via reusable middleware.

Best for: API input validation

#express#zod

Nodemailer Send Email with SMTP

Send transactional emails using Nodemailer with SMTP transport, HTML templates, and attachments.

Best for: Welcome emails

#email#nodemailer

Node.js Cron Job Scheduler

Schedule recurring tasks with node-cron using crontab syntax and timezone support.

Best for: Database cleanup tasks

#cron#scheduler

WebSocket Server with ws

Create a WebSocket server with connection tracking, heartbeat ping/pong, and typed message handling.

Best for: Chat applications

#websocket#realtime

JWT Refresh Token Rotation

Implement secure token rotation with short-lived access tokens and one-time-use refresh tokens.

Best for: Secure API authentication

#jwt#authentication

Bcrypt Password Hash & Verify

Hash and verify passwords with bcrypt using configurable salt rounds and timing-safe comparison.

Best for: User registration

#bcrypt#password

CSV Parse with Streaming

Parse large CSV files using Node.js streams with row-by-row processing and backpressure handling.

Best for: Data import pipelines

#csv#stream

S3 Presigned URL Generator

Generate secure presigned URLs for S3 upload and download operations with expiry and content type.

Best for: Direct browser uploads

#aws#s3

Node.js Worker Threads for Parallel Processing

Use Worker Threads to run CPU-intensive tasks in parallel without blocking the event loop.

Best for: CPU-intensive data processing without blocking

#nodejs#worker-threads

Node.js Stream Pipeline with Transform

Build efficient data processing pipelines using Node.js streams for large file handling.

Best for: Processing large CSV files without loading into memory

#nodejs#streams

TypeScript Typed Event Emitter

Create type-safe event emitters in Node.js with full TypeScript support and autocomplete.

Best for: Type-safe pub/sub communication between modules

#nodejs#events

Node.js Graceful Shutdown Handler

Implement graceful shutdown to properly close connections and finish requests before exit.

Best for: Production Node.js server reliability

#nodejs#shutdown

Node.js Crypto Utility Functions

Common cryptographic operations: hashing, HMAC, encryption, random tokens, and password hashing.

Best for: Secure password storage and verification

#nodejs#crypto

Node.js Recursive File Watcher

Watch files and directories for changes with debouncing and glob pattern filtering.

Best for: Custom hot-reload during development

#nodejs#file-system

Node.js Cluster Mode for Scaling

Scale Node.js across CPU cores using the cluster module with automatic worker respawning.

Best for: Utilizing all CPU cores for HTTP servers

#nodejs#cluster

Request Validation Schema Builder

Build a lightweight request validation layer with type inference for API endpoints.

Best for: API request body validation

#nodejs#validation

Node.js In-Memory Task Queue

A simple in-memory task queue with concurrency control, retries, and priority support.

Best for: Rate-limited API call processing

#nodejs#queue

Node.js Token Bucket Rate Limiter

Implement an in-memory token bucket rate limiter for controlling API request throughput.

Best for: Protecting APIs from abuse and DDoS

#nodejs#rate-limiting

Read and Write JSON Files

Read, parse, modify, and write JSON files with proper error handling using Node.js fs module.

Best for: Configuration file management

#nodejs#json

Cross-Platform Path Operations

Use Node.js path module for cross-platform file path manipulation, resolution, and normalization.

Best for: Cross-platform file path handling

#nodejs#path

Child Process: exec and spawn

Execute shell commands and spawn processes with exec, execFile, spawn, and fork in Node.js.

Best for: Running shell commands from Node.js

#nodejs#child-process

Native HTTP Server

Create a lightweight HTTP server using Node.js built-in http module with routing and JSON responses.

Best for: Lightweight API server without frameworks

#nodejs#http

Event Loop and Timers

Understand Node.js event loop phases with setTimeout, setInterval, setImmediate, and process.nextTick.

Best for: Understanding async execution order

#nodejs#event-loop

Streams: Readable, Writable, Transform

Build custom readable, writable, and transform streams for efficient data processing in Node.js.

Best for: Processing large files without loading into memory

#nodejs#streams

Custom Error Classes

Create typed custom error classes with HTTP status codes, error codes, and structured error handling.

Best for: Structured API error responses

#nodejs#error

Middleware Pattern and Composition

Implement the middleware pattern for composable request processing with next() and error handling.

Best for: Request processing pipelines

#nodejs#middleware

Promise Concurrency Patterns

Master Promise.all, allSettled, race, any — parallel execution with error handling and timeouts.

Best for: Parallel API calls with error handling

#nodejs#promise

Directory Operations with fs

Create, read, copy, and remove directories recursively using Node.js fs/promises.

Best for: Build tool directory management

#nodejs#fs

Compression with zlib

Compress and decompress data using gzip, deflate, and brotli with Node.js built-in zlib module.

Best for: API response compression

#nodejs#zlib

URL and Query String Parsing

Parse, construct, and manipulate URLs and query strings using the Node.js URL and URLSearchParams API.

Best for: API URL construction

#nodejs#url

Process Signals and Environment

Handle process signals, environment variables, exit codes, and unhandled errors in Node.js.

Best for: Graceful server shutdown

#nodejs#process

Buffer and Binary Data

Work with binary data using Node.js Buffer: create, convert, slice, encode/decode, and compare.

Best for: Binary protocol implementation

#nodejs#buffer

Native Test Runner and Assert

Write tests using Node.js built-in test runner and assert module — no external dependencies needed.

Best for: Unit testing without external packages

#nodejs#testing

Crypto Hashing and HMAC

Generate secure hashes, HMACs, and checksums using Node.js built-in crypto module.

Best for: Webhook signature verification

#nodejs#crypto

AbortController for Cancellation

Cancel async operations with AbortController: fetch requests, timers, streams, and custom operations.

Best for: Request timeout handling

#nodejs#abort

Performance Measurement

Measure execution time with performance.now(), Performance API marks, measures, and PerformanceObserver.

Best for: Function execution profiling

#nodejs#performance

Typed Event Emitter Class

Build a type-safe event emitter with TypeScript generics for strongly-typed event handling.

Best for: Type-safe event-driven architecture

#nodejs#events

Interactive CLI with Readline

Build interactive command-line interfaces using Node.js readline with prompts, history, and auto-completion.

Best for: Building simple CLI tools

#nodejs#readline

DNS Lookup and Resolution

Perform DNS lookups, resolve hostnames to IP addresses, and query DNS records using Node.js dns module.

Best for: Network diagnostics tools

#nodejs#dns

System Information with OS Module

Retrieve system information including CPU, memory, network interfaces, and platform details using os module.

Best for: Server health dashboards

#nodejs#os

HTTP/2 Server with Stream Push

Create an HTTP/2 server with server push, multiplexed streams, and TLS configuration in Node.js.

Best for: High-performance web servers

#nodejs#http2

Async Iterators for Stream Processing

Process streams and async data sources with for-await-of loops and custom async iterators in Node.js.

Best for: Paginated API data consumption

#nodejs#async-iterator

Cluster Worker Pool Pattern

Distribute CPU-intensive tasks across worker processes with automatic restart and load balancing.

Best for: Multi-core CPU utilization

#nodejs#cluster

TCP Server and Client with Net Module

Build TCP server and client pairs using Node.js net module with connection pooling and message framing.

Best for: Custom protocol implementation

#nodejs#tcp

Event-Driven Architecture Pattern

Build loosely coupled systems with typed event bus, async event handlers, and domain event patterns.

Best for: Microservice communication

#nodejs#events

JavaScript Proxy Handler Pattern

Use Proxy and Reflect to create observable objects, validation layers, and dynamic API clients.

Best for: Observable state management

#nodejs#proxy

Schema Validation with Zod-like Patterns

Build a minimal schema validation library inspired by Zod using TypeScript type inference.

Best for: API request validation

#nodejs#validation

Express Error Handling Middleware

Centralized error handling in Express with custom error classes, async wrapper, and structured responses.

Best for: API error standardization

#nodejs#express

#nodejs#dependency-injection

Dependency Injection Container

Build a lightweight DI container with singleton and transient scopes for testable Node.js applications.

Best for: Testable application architecture

Semaphore for Concurrency Limiting

Control concurrent async operations with a semaphore pattern: rate limiting, connection pooling, and batch processing.

Best for: API rate limiting

#nodejs#concurrency

In-Memory Caching with LRU Strategy

Implement LRU cache with TTL expiration, size limits, and cache-aside pattern for Node.js applications.

Best for: API response caching

#nodejs#caching

Retry with Exponential Backoff

Retry failed async operations with exponential backoff, jitter, and configurable retry conditions.

Best for: API call resilience

#nodejs#retry

Promise Pool for Batch Processing

Process large arrays with controlled concurrency using a promise pool pattern with progress tracking.

Best for: Bulk API requests

#nodejs#promise

Type-Safe Configuration Loader

Load and validate configuration from environment variables with type coercion and required field checks.

Best for: Application configuration management

#nodejs#config

Structured JSON Logger

Build a structured logger with log levels, context, child loggers, and JSON output for Node.js services.

Best for: Application logging for production

#nodejs#logging

Middleware Chain Pattern

Implement the middleware/pipeline pattern for composable request processing without Express.

Best for: Custom HTTP framework

#nodejs#middleware

Fastify Server Setup

Create a high-performance Fastify server with schema validation, plugins, and typed routes.

Best for: High-performance REST APIs

#nodejs#fastify

CORS Configuration Middleware

Configure Cross-Origin Resource Sharing with origin allowlists, credentials, and preflight handling.

Best for: API CORS configuration

#nodejs#cors

Secure Cookie and Session Management

Handle HTTP cookies with signing, encryption, and session management using secure defaults.

Best for: Authentication session handling

#nodejs#cookies

GraphQL Server with Type Definitions

Build a GraphQL API server with type definitions, resolvers, and query/mutation support.

Best for: GraphQL API development

#nodejs#graphql

Health Check Endpoint Pattern

Implement comprehensive health checks with dependency status, uptime, and readiness probes.

Best for: Kubernetes liveness probes

#nodejs#health-check

Webhook Handler with Signature Verification

Process incoming webhooks with HMAC signature verification, replay protection, and idempotency.

Best for: GitHub/Stripe webhook processing

#nodejs#webhook

Cursor-Based Pagination API

Implement cursor-based pagination with forward/backward navigation, consistent ordering, and link headers.

Best for: REST API pagination

#nodejs#pagination

API Versioning Strategy

Implement API versioning with URL path, header-based, and content negotiation strategies.

Best for: API backward compatibility

#nodejs#api

Debug with Inspector Protocol

Programmatic debugging with Node.js inspector module for heap snapshots, CPU profiling, and breakpoints.

Best for: Production performance profiling

#nodejs#debugging

ESM and CJS Module Interop

Handle ECMAScript module and CommonJS interop with dynamic imports, conditional exports, and dual packages.

Best for: Library dual packaging

#nodejs#esm

Application Metrics Collection

Collect and expose application metrics like request counts, latency histograms, and custom gauges.

Best for: Prometheus metrics endpoint

#nodejs#monitoring

Pub/Sub Messaging Pattern

Implement publish/subscribe messaging with topics, filtered subscriptions, and message replay.

Best for: In-process event messaging

#nodejs#pubsub

Request ID Tracing Middleware

Express middleware that generates or forwards X-Request-Id headers for distributed tracing.

Best for: Distributed tracing

#express#tracing

ETag Caching Middleware

Express middleware that generates ETags and handles 304 Not Modified responses for bandwidth savings.

Best for: API caching

#express#caching

#resilience#microservices

Circuit Breaker Pattern

Implements the circuit breaker pattern to prevent cascading failures when calling external services.

Best for: External API calls

IP Geolocation Middleware

Extracts client IP and attaches geolocation data to the request using a lightweight lookup.

Best for: Content localization

#express#geolocation

Response Compression Middleware

Native zlib-based middleware that gzip-compresses responses above a size threshold.

Best for: Reducing API payload size

#express#compression

Request Timeout Middleware

Express middleware that aborts requests exceeding a configurable time limit with 408 status.

Best for: Preventing hanging requests

#express#timeout

API Key Authentication Middleware

Simple API key validation middleware that checks the X-API-Key header against a set of valid keys.

Best for: Public API authentication

#express#authentication

Multipart Upload Stream Handler

Handles multipart file uploads with streaming to disk without buffering the entire file in memory.

Best for: Large file uploads

#upload#streaming

Graceful HTTP Server Shutdown

Production-ready server shutdown that drains active connections and closes resources cleanly.

Best for: Container deployments

#server#shutdown

Structured Request Logger Middleware

Express middleware that logs request/response details as structured JSON with timing information.

Best for: API monitoring

#express#logging

Promise Queue with Concurrency Limit

A queue that processes async tasks with a configurable concurrency limit to prevent resource exhaustion.

Best for: Rate-limited API calls

#async#concurrency

Environment Secrets Loader

Loads and validates required environment variables at startup and throws meaningful errors for missing ones.

Best for: Application bootstrap

#env#config

Server-Sent Events Handler

Express route that implements SSE for real-time server-to-client push notifications.

Best for: Live notifications

#sse#real-time

In-Memory Response Cache

Simple TTL-based in-memory cache middleware for GET endpoints that serves cached responses.

Best for: Caching expensive queries

#cache#performance

Idempotency Key Middleware

Prevents duplicate request processing by caching responses keyed by the Idempotency-Key header.

Best for: Payment processing

#idempotency#api

OpenAPI Request Validator

Validates incoming request body against a JSON schema derived from an OpenAPI spec.

Best for: API input validation

#openapi#validation

Webhook Signature Verification

Verifies HMAC-SHA256 webhook signatures to ensure payloads are from trusted sources.

Best for: GitHub webhook handlers

#webhook#security

JSON Stream Parser

Parses large JSON arrays from a readable stream without loading the entire file into memory.

Best for: Processing large log files

#streaming#json

Health, Readiness & Liveness Checks

Express routes implementing Kubernetes-style health, readiness, and liveness probe endpoints.

Best for: Kubernetes deployments

#health-check#kubernetes