Configure and debug your development environment.
Validate .env files, build configuration, and convert it for your runtime. Follow practical guides for Docker, local development and CI/CD. Free, no signup.
Developer Tools
.env Validator
Check syntax and compare example keys
.env Builder
Generate env files for your stack
.env Converter
Convert literal .env values for deployment
JSON Formatter & Validator
Prettify and validate instantly
Base64 Encode / Decode
Encode and decode text, URLs and files
IP Subnet Calculator
CIDR to IP range with visual breakdown
JWT Debugger
Decode, inspect and verify tokens
Browse all tools →Featured Guides
View all 95 guides →The .env File: A Complete Guide to Environment Variables
Everything about .env files: syntax rules, parser quirks, language examples (Node, Python, Go, Docker), best practices, and the gotchas that bite.
Docker Compose Environment Variables: The Complete Guide
Use environment variables in Docker Compose: .env auto-load, env_file, --env-file, multi-environment patterns, substitution, and secrets.
.env File Syntax Rules: Quoting, Comments, Multiline
Compare measured .env parsing in Node, npm dotenv, Python, Docker Compose, and Docker CLI: whitespace, comments, quotes, multiline values, and expansion.
dotenv Not Loading? Step-by-Step Debugging Guide
Fix environment variables not loading from .env files. Covers Node.js, Python, Docker, file path issues, syntax errors, load order, and production gotchas.
Dev Containers: Guide to Containerized Development
Dev Containers from devcontainer.json to Features, lifecycle scripts, Docker Compose, the CLI, performance tuning, security, and the gotchas.
Neovim: A Developer Guide to the Modern Vim
Master Neovim: modes, motions, text objects, registers, built-in LSP, Tree-sitter, Lua configuration, lazy.nvim plugins, and macros.
Recently updated
Guide
Dev Container Environment Variables
Set Dev Container variables with containerEnv, remoteEnv, localEnv, and Docker Compose without confusing process scope or precedence.
Guide
Cloudflare Workers Environment Variables
Configure Workers bindings, secrets, Wrangler environments, local .dev.vars precedence, and Node process.env behavior.
Guide
uv Environment Variables and .env Files
Load .env files with uv run, apply later-file and shell precedence, disable loading, and separate app variables from uv configuration.
Guide
GitHub Actions: Secrets vs Environment Variables
When to use repository secrets, environment secrets, and configuration variables in GitHub Actions. Includes workflow examples for Node.js, Python, and Docker.
Guide
.env File Syntax Rules: Quoting, Comments, Multiline
Compare measured .env parsing in Node, npm dotenv, Python, Docker Compose, and Docker CLI: whitespace, comments, quotes, multiline values, and expansion.
Guide
dotenv Not Loading? Step-by-Step Debugging Guide
Fix environment variables not loading from .env files. Covers Node.js, Python, Docker, file path issues, syntax errors, load order, and production gotchas.
send.env.dev — share .env files, API keys, and secrets, end-to-end encrypted
Stop pasting secrets into Slack, email, or chat. send.env.dev is end-to-end encrypted — only you and the recipient can ever read the secret. Not us, not your network, not anyone in between. Links self-destruct after the first read and expire within 24 hours.
- 🔐 Two-factor: URL key + passphrase
- 🔥 Self-destructs after one read
- ⏱️ Auto-expires
- 🇪🇺 EU data residency (GDPR)
References
Cursor
AI-native VS Code fork. Cursor 3 ships an Agents Window for parallel agents across local, worktrees, SSH, and cloud VMs. Composer 2 is the default model.
Windsurf
AI-powered IDE by Codeium with Cascade, an agentic LLM coding assistant that understands your full codebase.
GitHub Copilot
AI pair programmer by GitHub. LLM-powered autocomplete, chat, and agent mode integrated into VS Code and JetBrains.
Claude Code
Anthropic's CLI-based agentic LLM coding tool. Terminal-first AI assistant for complex multi-file tasks.
OpenCode
Open-source MIT-licensed terminal AI coding agent. BYO-model, MCP-native, signs in with your GitHub Copilot subscription.
Codeium
Free AI code completion tool. Fast LLM-powered autocomplete for 70+ languages across all major editors.
The AI Dark Factory Playbook
A 5-part series on AI-driven development — from manual coding to autonomous agents.
Start here · Primer
AI Dark Factory: Autonomous Coding Explained
AI dark factory: autonomous coding where agents write, test, and ship without human review. Coined by Dan Shapiro, Glowforge, January 2026.
Or jump straight to a part
Popular Comparisons
View all 11 comparisons →Comparison
Bun vs Deno vs Node.js: Which Runtime in 2026?
Compare Bun 1.3, Deno 2.7, and Node.js 24 LTS. Benchmarks for cold start, throughput, and install speed; how each handles .env files; and when to pick which.
Comparison
REST vs GraphQL: Which API Style Should You Use?
Compare REST and GraphQL APIs side by side. The trade-offs in performance, flexibility, caching, and developer experience, and how to choose.
Comparison
Docker vs Kubernetes: What's the Difference?
Understand the difference between Docker and Kubernetes. Docker builds and runs containers; Kubernetes orchestrates them at scale. Learn when to use each.
Comparison
npm vs yarn vs pnpm: Package Manager Comparison
Compare npm, yarn, and pnpm package managers. Benchmark install speed, disk usage, lockfile format, and monorepo support to pick the best one for your project.
Comparison
PostgreSQL vs MySQL: Which Database to Choose?
Compare PostgreSQL and MySQL databases. Analyze performance, features, JSON support, replication, and ecosystem to choose the right database for your project.
Comparison
Redis vs Memcached: In-Memory Caching Compared
Compare Redis and Memcached for caching. Evaluate data structures, persistence, clustering, and use cases to pick the right in-memory store.
Cheatsheets
View all 35 cheatsheets →Docker Compose Cheat Sheet — CLI, Health Checks & Watch
Docker Compose commands, compose.yaml keys, depends_on health conditions, profiles, and develop.watch live reload — plus the gotchas that break stacks.
sed & awk Cheat Sheet — Text Processing One-Liners
sed and awk one-liners for substitution, line ranges, field extraction, and aggregation — with the GNU vs BSD traps that break scripts on macOS.
PowerShell Cheat Sheet — Cmdlets, Pipeline & Objects
PowerShell 7 cmdlets, the object pipeline, filtering, environment variables, and execution policy — plus what differs from Windows PowerShell 5.1.
OpenGraph Meta Tags Cheat Sheet — Sizes, Tags, Twitter Cards
Every OpenGraph and Twitter Card tag with recommended image sizes per platform (Facebook, LinkedIn, X, Slack, Discord) and a copyable HTML template.
HTTP Status Codes — Complete Quick Reference
Every HTTP status code explained with practical examples. 1xx through 5xx with when to use each code in your API.
CIDR Notation Cheat Sheet — Subnet Masks & Host Counts
Complete CIDR reference table: every prefix from /8 to /32 with subnet mask, total addresses, usable hosts, and common use cases.
Discounts
Browse all discounts →AWS Activate
Up to $100k in AWS credits for startups. Apply through the AWS Activate program with your startup details.
$2k+ creditsGoogle Cloud for Startups
Over $2,000 in Google Cloud credits for eligible startups. Apply through the Google for Startups program.
$150k creditsMicrosoft for Startups (Azure)
Up to $150k in Azure credits plus free access to Microsoft tools. Apply through the Microsoft for Startups Founders Hub.
$200 creditsDigitalOcean Hatch
$200 in infrastructure credits for startups. Apply through the Hatch startup program with your company details.
Free tierCloudflare
Generous free tier including CDN, DNS, DDoS protection, and Workers. Available to everyone, just sign up.
Free tierVercel
Free hobby tier with hosting, edge functions, and serverless deployments. Sign up with your personal account.
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