Development · Tip
Cross-Subdomain Cookies in Better Auth
Share authentication sessions across multiple subdomains using Better Auth configuration.
This configuration tip shows how to share authentication cookies across multiple subdomains with Better Auth. By setting the root domain under the advanced options, an authentication server on one subdomain can handle sessions for apps on other subdomains.
How it works
To make auth.site.com your auth server and authenticate other subdomains like app.site.com or your.site.com, enable crossSubDomainCookies in the betterAuth config: advanced: { crossSubDomainCookies: { enabled: process.env.NODE_ENV === "production", domain: "site.com" } }. This shares cookies between the subdomains.
What it's for
- Authenticate multiple apps under the same root domain from a single auth server
- Share session states between app subdomains and an auth subdomain
- Avoid complex token-passing setups across internal domain services
Key points
- Configure crossSubDomainCookies under the advanced settings key
- Set the base domain to allow cookie visibility across all subdomains
- Conditionally enable domain scoping based on environment
Pricing
Free
Details
- Type
- Tip
- Category
- Development
- Topic
- Authentication
- Open source
- Yes
- Platforms
- Code library
- For
- Developers using Better Auth across multi-subdomain architectures
- Tags
- better auth, cookies, authentication, typescript, subdomains, web dev
Why it was saved
- @bekacru: Lets auth.site.com authenticate app.site.com and other subdomains without fancy setup
Related
Annual overview of the fastest-growing JavaScript GitHub repositories in 2023.
Open-source TypeScript authentication framework for modern web applications.
Full-stack SaaS starter with Next.js 15, Convex, and Clerk Billing
Full-stack Next.js 15 starter with Better-Auth, Drizzle, and Tailwind v4
Render structured JSON specifications into PDFs using React PDF
Tutorial explaining session token replay for internal X API access
Updated