build vs buy auth

If you mean “should we build authentication ourselves or buy/use a provider?” the short answer is:

• Buy if you want to ship fast, reduce security risk, and avoid ongoing auth maintenance.
• Build only if auth is a core differentiator, you have unusual requirements, or you need deep control over the user/session model.

Usually buy if:

• You need standard login features:
  • email/password
  • social login
  • MFA/2FA
  • password reset
  • magic links
  • SSO/OIDC/SAML
• You care about security and compliance
• You have a small team
• You want faster time to market

Common choices:

• Auth0 / Okta
• Clerk
• Firebase Auth
• Cognito
• Supabase Auth
• WorkOS (especially for B2B SSO/SCIM)

Consider building if:

• Authentication is your product
• You need highly custom flows or trust models
• You have strict regulatory/data residency constraints
• You need to own every part of identity/session infrastructure
• You have the security expertise and bandwidth to maintain it

Hidden costs of building:

• password storage and hashing
• account recovery
• email verification
• brute-force protection
• session management
• token refresh/rotation
• MFA
• social login integrations
• account linking
• audit logs
• abuse prevention
• compliance and incident response

A practical rule:

• Consumer app / startup: buy
• B2B SaaS: usually buy, maybe combine with WorkOS
• Large enterprise or identity company: maybe build

Common compromise:

Use a provider for core auth, but build:

• roles/permissions
• app-specific authorization
• org/team membership
• custom profile logic
• product-specific onboarding

If you want, I can also give you:

1. a decision matrix,
2. a cost comparison, or
3. a recommendation for your exact product.