@supabase/auth-js

Supabase Auth JS SDK

An isomorphic JavaScript SDK for the Supabase Auth API.

Guides · Reference Docs · TypeDoc

Requirements

• Node.js 20 or later (Node.js 18 support dropped as of October 31, 2025)
• For browser support, all modern browsers are supported

⚠️ Node.js 18 Deprecation Notice

Node.js 18 reached end-of-life on April 30, 2025. As announced in our deprecation notice, support for Node.js 18 was dropped on October 31, 2025.

Quick start

Install

npm install --save @supabase/auth-js

Usage

import { AuthClient } from '@supabase/auth-js'

const GOTRUE_URL = 'http://localhost:9999'

const auth = new AuthClient({ url: GOTRUE_URL })

• signUp(): https://supabase.com/docs/reference/javascript/auth-signup
• signIn(): https://supabase.com/docs/reference/javascript/auth-signin
• signOut(): https://supabase.com/docs/reference/javascript/auth-signout

Custom fetch implementation

auth-js uses the cross-fetch library to make HTTP requests, but an alternative fetch implementation can be provided as an option. This is most useful in environments where cross-fetch is not compatible, for instance Cloudflare Workers:

import { AuthClient } from '@supabase/auth-js'

const AUTH_URL = 'http://localhost:9999'

const auth = new AuthClient({ url: AUTH_URL, fetch: fetch })

Development

This package is part of the Supabase JavaScript monorepo. To work on this package:

Building

# Complete build (from monorepo root)
npx nx build auth-js

# Build with watch mode for development
npx nx build auth-js --watch

# Individual build targets
npx nx build:main auth-js    # CommonJS build (dist/main/)
npx nx build:module auth-js  # ES Modules build (dist/module/)

# Other useful commands
npx nx lint auth-js          # Run ESLint
npx nx typecheck auth-js     # TypeScript type checking
npx nx docs auth-js          # Generate documentation

Build Outputs

• CommonJS (dist/main/) - For Node.js environments
• ES Modules (dist/module/) - For modern bundlers (Webpack, Vite, Rollup)
• TypeScript definitions (dist/module/index.d.ts) - Type definitions for TypeScript projects

Testing

The auth-js package has two test suites:

• CLI Tests - Main test suite using Supabase CLI (331 tests)
• Docker Tests - Edge case tests requiring specific GoTrue configurations (11 tests)

Prerequisites

• Supabase CLI - Required for main test suite (installation guide)
• Docker - Required for edge case tests

Running Tests

# Run main test suite with Supabase CLI (recommended)
npx nx test:auth auth-js

# Run Docker-only edge case tests
npx nx test:docker auth-js

# Run both test suites
npx nx test:auth auth-js && npx nx test:docker auth-js

Main Test Suite (Supabase CLI)

The test:auth command automatically:

• Stops any existing Supabase instance
• Starts a local Supabase instance via CLI
• Runs the test suite (excludes docker-tests/ folder)
• Cleans up after tests complete

# Individual commands for manual control
npx nx test:infra auth-js    # Start Supabase CLI
npx nx test:suite auth-js    # Run tests only
npx nx test:clean-post auth-js  # Stop Supabase CLI

Docker Tests (Edge Cases)

The test:docker target runs tests that require specific GoTrue configurations not possible with a single Supabase CLI instance:

• Signup disabled - Tests for disabled signup functionality
• Asymmetric JWT (RS256) - Tests for RS256 JWT verification
• Phone OTP / SMS - Tests requiring Twilio SMS provider
• Anonymous sign-in disabled - Tests for disabled anonymous auth

These tests are located in test/docker-tests/ and use the Docker Compose setup in infra/docker-compose.yml.

# Individual commands for manual control
npx nx test:docker:infra auth-js    # Start Docker containers
npx nx test:docker:suite auth-js    # Run Docker tests only
npx nx test:docker:clean-post auth-js  # Stop Docker containers

Development Testing

For actively developing and debugging tests:

# Start Supabase CLI once
npx nx test:infra auth-js

# Run tests multiple times (faster since instance stays up)
npx nx test:suite auth-js

# Clean up when done
npx nx test:clean-post auth-js

Test Infrastructure

Suite	Infrastructure	Configuration
CLI Tests	Supabase CLI	test/supabase/config.toml
Docker Tests	Docker Compose	infra/docker-compose.yml

Contributing

We welcome contributions! Please see our Contributing Guide for details on how to get started.

For major changes or if you're unsure about something, please open an issue first to discuss your proposed changes.

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