Gitignore Generator

The Problem

A developer joins the team, clones the repo, runs npm install, and pushes. Their .env file with database passwords gets committed because the root .gitignore was created from a Python template and doesn't include Node.js patterns. Three months later, someone runs git log --all --diff-filter=A -- "*.env" and finds 14 .env files in the history — each containing different credentials that were supposed to be secret.

Or the repo has 50MB of node_modules/ in git history because .gitignore was added after the files were already tracked (.gitignore only affects untracked files). Or a developer's .vscode/settings.json with personal paths and preferences gets committed, causing conflicts on every machine. Or __pycache__/ directories litter the repo because someone added Python files from a Windows machine where the pyc patterns weren't caught.

Every one of these is a .gitignore gap that a proper generator would have caught.

What You Get

• Automatic stack detection — scans for package.json, requirements.txt, Cargo.toml, go.mod, pom.xml, build.gradle, Gemfile, composer.json, *.csproj, CMakeLists.txt, Dockerfile, and framework-specific indicators (Next.js, Django, Flask, Terraform)
• Sensitive file scan — finds .env, .env.*, *.pem, *.key, *.p12, secrets.*, id_rsa, *.token, .npmrc, .pypirc and checks if they're git-tracked
• Seven-section generated .gitignore — Secrets/Sensitive (universal), OS Generated Files, Editor/IDE, Logs, Dependency Directories, then stack-specific sections for Python, Node.js, Java, Go, Rust, Docker, Terraform, and Ruby
• Existing file audit — checks for tracked files that should be ignored (git ls-files | grep), missing common patterns, duplicate entries, and syntax errors (broken negations, incorrect ** usage, missing trailing slashes)
• Already-tracked remediation — provides git rm --cached commands to untrack files without deleting them, and git filter-repo instructions for secrets already in history
• Monorepo awareness — handles combined patterns for multiple stacks in a single repo without ignoring files needed by one subproject but not another

Why This Beats Prompting It Yourself

Copy-pasting from gitignore.io gives you a template — it doesn't check whether your .env is already tracked, whether your existing file has gaps, or whether you're in a monorepo where a root-level pattern might accidentally ignore files in a subproject. The generator detects your actual stack, scans for sensitive files that are already committed (the most urgent finding), and produces a file organized by category with a date header so future developers know when it was last reviewed.

Example Session

You: "Generate a .gitignore for this project. It's a Next.js app with a Python backend."

Agent:

Stacks found: Node.js (package.json), Python (requirements.txt), Docker
Sensitive files found: .env (tracked!), .env.local (tracked!)

git ls-files .env .env.local → Both tracked ⚠️
Remediation:
  git rm --cached .env .env.local
  echo ".env" >> .gitignore
  echo ".env.local" >> .gitignore
  git commit -m "chore: untrack sensitive env files"

[Sections: Secrets | OS | Editor | Logs | Python | Node.js | Docker]

.env*                  ← catches .env, .env.local, .env.production
*.pem, *.key           ← certificates and private keys
__pycache__/, *.pyc    ← Python bytecode
node_modules/          ← npm dependencies
.next/                 ← Next.js build output
.DS_Store              ← macOS junk
.vscode/, .idea/       ← IDE configs
*.log                  ← log files

Use Cases

• New repository initialization — create a comprehensive .gitignore from the start before any sensitive files are committed
• Existing repo audit — scan for tracked files that should be ignored and gaps in coverage
• Secret exposure response — after accidentally committing .env, generate the right patterns and provide cleanup commands
• Monorepo setup — generate combined patterns for multi-stack repositories without pattern conflicts
• Framework migration — update patterns when switching from one framework/stack to another (e.g., adding Python backend to a Node.js frontend)

Known Limitations

The generator creates patterns based on common conventions for each stack — custom or unusual project structures may need manual additions. Already-committed files in git history require git filter-repo or BFG to fully remove, not just git rm --cached. The tool generates the .gitignore file but does not automatically run the remediation commands — the user reviews and executes them.