# Firebase Basics

> Firebase CLI foundation for any project. Use when checking Firebase CLI version, authenticating with Firebase, setting active projects, initializing Firebase services, or running Firebase MCP commands. Triggers: firebase login, firebase use, firebase projects list, firebase init, firebase MCP, Firebase CLI setup, Firebase emulator start.

- Skill: `kumaran-is/firebase-basics` (Agent Skill)
- Install (CLI): `npx skillmds@latest add kumaran-is/firebase-basics`
- Raw SKILL.md: https://api.skillmd.com/api/skills/kumaran-is/firebase-basics/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: kumaran-is (https://skillmd.com/u/kumaran-is)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/kumaran-is/firebase-basics

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## Iron Law

**NEVER use the naked `firebase` binary — always `npx -y firebase-tools@latest <cmd>`.**

This guarantees the latest CLI version is used without polluting global node_modules.
Every command in this skill prepends `npx -y firebase-tools@latest`.

## Project Context

Check the project's `CLAUDE.md` to understand which Firebase services are in use and any
project-specific constraints (e.g. which services are intentionally NOT used, whether
Firestore is used as a canonical store or a status bus only, etc.).

Firebase project ID should be stored in an environment variable (e.g. `FIREBASE_PROJECT_ID`)
— never hardcoded.

# Prerequisites

1. **Local Environment Setup:**
   ```bash
   npx -y firebase-tools@latest --version
   ```
   Read [references/local-env-setup.md](references/local-env-setup.md) for full setup.

2. **Authentication:**
   ```bash
   npx -y firebase-tools@latest login
   # Headless / remote shell:
   npx -y firebase-tools@latest login --no-localhost
   ```

3. **Active Project:**
   ```bash
   npx -y firebase-tools@latest use
   # Set project from env var (preferred):
   npx -y firebase-tools@latest use --add ${FIREBASE_PROJECT_ID}
   ```

# Firebase Usage Principles

1. **npx always:** `npx -y firebase-tools@latest <cmd>` — never bare `firebase`
2. **Consult Firebase MCP first:** Use `developerknowledge_search_documents` before
   falling back to web search or memory
3. **Use Firebase MCP tools for remote API calls:** Crashlytics, Firestore queries,
   project management — always MCP, never manual REST calls
4. **Emulator for local dev:** Set `FIREBASE_AUTH_EMULATOR_HOST` and related emulator
   environment variables — without them, Admin SDK calls hit production Firebase with
   dev tokens

# References

- **Initialize services:** [references/firebase-service-init.md](references/firebase-service-init.md)
- **CLI commands:** [references/firebase-cli-guide.md](references/firebase-cli-guide.md)
- **Local env setup:** [references/local-env-setup.md](references/local-env-setup.md)

# Related Skills

- `flutter-mobile` — Firebase Auth integration in Flutter apps
- `firebase-hosting-basics` — deploy static SPA to Firebase Hosting
- `security-reviewer` — Firestore Security Rules audit