Email/Password Login Flow
Overview
A traditional login system where users authenticate using their email address and password. The system validates credentials, creates a secure session, and provides appropriate error handling for invalid attempts.
User Stories
- As a user, I want to log in with my email and password, so that I can access my account
- As a user, I want to see clear error messages if my credentials are incorrect, so that I know what went wrong
- As a user, I want to stay logged in across browser sessions, so that I don't have to re-enter my credentials every time
- As a user, I want the option to log out, so that I can secure my account when using shared devices
Acceptance Criteria
- [ ] Login form accepts email and password inputs
- [ ] Form validates email format before submission
- [ ] Password field masks characters for security
- [ ] System displays specific error messages (invalid email, wrong password, account locked)
- [ ] Successful login redirects to dashboard or intended page
- [ ] Session persists for 30 days with "Remember me" option
- [ ] Failed login attempts are rate-limited (max 5 attempts per 15 minutes)
- [ ] User can navigate to password reset from login page
Technical Requirements
- Hash passwords using bcrypt or Argon2 with salt
- Implement CSRF protection on login endpoint
- Store sessions in secure, httpOnly cookies
- Use HTTPS for all authentication requests
- Log authentication attempts for security monitoring
- Implement account lockout after 5 failed attempts
Edge Cases
- User enters email that doesn't exist → Show generic "Invalid credentials" message (prevent email enumeration)
- User account is locked → Display message with unlock time or support contact
- Session expires during active use → Redirect to login with return URL
- Multiple concurrent sessions → Allow or force logout based on security policy
- SQL injection attempts in login form → Sanitize all inputs, use prepared statements
Out of Scope
- Social login (OAuth)
- Multi-factor authentication
- Magic link login
- Passwordless authentication