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Looking for .env? Read the complete guide to environment variable files.
Featured Guides
View all 75 guides →Guide
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.
Guide
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.
Guide
The Complete .env File Syntax Reference
.env file syntax reference: quoting, comments, multiline values, variable expansion, and the parser differences across Node.js, Python, Ruby, Go, and Docker.
Guide
AI Dark Factory Playbook: From Autocomplete to Autonomous
Six-level AI dark factory playbook from manual coding (Level 0) to fully autonomous code (Level 5). Concrete actions for agentic coding, real-world numbers, no hype.
Guide
Environment Variables in Rust: std::env, dotenvy & envy
Read env vars in Rust with std::env::var, load .env files via dotenvy, and deserialize typed config with envy. Plus the Rust 2024 unsafe-set_var change.
Guide
OpenGraph Image Sizes 2026: Per-Platform Cheat Sheet
Recommended OpenGraph image sizes per platform in 2026: universal safe size, aspect ratios, file size limits, and how each platform crops on mobile.
Recently updated
Guide
Node.js Env Variables: process.env, dotenv & --env-file
How to use environment variables in Node.js: process.env, dotenv, the Node 20.6+ --env-file flag, NODE_ENV, type-safe validation with zod.
Guide
Fix 'NODE_NO_WARNINGS is not recognized' on Windows
On Windows, NODE_NO_WARNINGS=1 node app.js fails because cmd parses the inline env var as a command. Fix it with set, PowerShell's $env:, cross-env, or Node's --disable-warning flag.
Guide
Gemini API Environment Variables: Keys & Vertex AI
GEMINI_API_KEY and GOOGLE_API_KEY both auto-load in the google-genai SDK; GOOGLE_API_KEY wins if both are set. Vertex AI needs project + location, not a key. Legacy SDKs hit EOL 2025-11-30.
Update
Anthropic moves Claude Agent SDK and `claude -p` to a credit pool
From June 15, 2026, Claude Agent SDK and `claude -p` usage stops drawing from your subscription rate limits and starts draining a separate $20 (Pro) / $100 (Max 5x) / $200 (Max 20x) monthly credit. What you need to do before the cutover.
Guide
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.
Guide
Environment Variables in Rust: std::env, dotenvy & envy
Read env vars in Rust with std::env::var, load .env files via dotenvy, and deserialize typed config with envy. Plus the Rust 2024 unsafe-set_var change.
send.env.dev — the #1 secure way to send .env files, API keys, and secrets to your team
Stop pasting secrets into Slack, email, or chat. send.env.dev is truly 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)
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
Developer Tools
Browse all tools →.gitignore Generator
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
Client-side utilities — JSON formatter, Base64 encoder, UUID generator, and more.
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. Understand the trade-offs in performance, flexibility, caching, and developer experience to choose the right approach.
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.
References
Environment Variables
100+ environment variables across AWS, Azure, Docker, Node.js and more — with best practices and a .env validator.
Browse variables →Programming Constants
Essential constants across JavaScript, Python, Go, Rust and more — values, types, and best practices.
Browse constants →Everything starts with env
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.
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.
Latest Guides
View all 75 guides →Local LLMs for Coding in 2026: Models, Hardware, Runtimes
Local LLMs for coding in 2026: Qwen2.5-Coder 32B at 73.7 Aider, Ollama vs llama.cpp vs LM Studio, and how to point Cursor or Continue at localhost.
jq: Filter and Transform JSON From the Command Line
jq is the C-based JSON processor (1.8.1, 2025) that filters, reshapes, and pipes JSON inside shell scripts. Real-world recipes for kubectl, GitHub API, and AWS CLI.
tmux: Sessions, Panes, .tmux.conf, and Neovim Integration
tmux is the BSD-licensed terminal multiplexer (3.6a, 2026) that survives SSH drops and reboots. Sessions, panes, .tmux.conf, scripting, and the Neovim handshake.
Docker on Windows 2026: Desktop, WSL2, Rancher, Podman
Docker on Windows runs four ways in 2026: Docker Desktop, Docker Engine in WSL2, Rancher Desktop, or Podman Desktop. Licensing, performance, and how to pick.
How to Build an MCP Server: TypeScript & Python (2026)
Build a Model Context Protocol server in TypeScript or Python in 2026: SDK quickstart, transports (stdio vs Streamable HTTP), security, and client setup.
OpenGraph Image Not Showing: 8 Causes and Fixes
Why your og:image is not rendering on Facebook, LinkedIn, Slack, Discord, or iMessage — caching, absolute URLs, size limits, hotlink protection, and robots.txt blocks.
Cheatsheets
View all 32 cheatsheets →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.
YAML Syntax Cheat Sheet — Scalars, Collections & Gotchas
Quick reference for YAML syntax: strings, numbers, multiline values, sequences, mappings, anchors, aliases, and common gotchas like the Norway problem.
JSON Cheat Sheet — Syntax, Parsing & Common Mistakes
Quick reference for JSON syntax: data types, objects, arrays, JSON.parse/stringify, jq basics, and common mistakes like trailing commas and single quotes.
Cron Schedule Examples — 30+ Common Cron Expressions
Ready-to-use cron expressions for every common schedule: every 5 minutes, hourly, daily, weekly, monthly, and more.
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