Users under 13 blocked from accounts or routed to COPPA-compliant experience

COPPA §312.5 and §312.3 require that when a child is identified as under 13, no personal information is collected or stored unless verifiable parental consent is obtained. A client-side block that the server ignores is not a block — it is a UI illusion. If the account creation API processes a submission regardless of the submitted age, the operator is collecting personal information from an identified child without consent, which is a direct COPPA §312.5 violation. The FTC does not require intent; the data being stored is sufficient to establish the violation.

Enforce the under-13 block at the API layer, not just in the form component. The route below validates age, sets a short-lived age_blocked cookie to deter immediate retry, and returns a 403 before writing any data.

// app/api/auth/signup/route.ts
import { cookies } from 'next/headers'

export async function POST(req: Request) {
  const { email, password, dateOfBirth } = await req.json()
  const ageYears = computeAge(new Date(dateOfBirth))

  if (ageYears < 13) {
    cookies().set('age_blocked', '1', {
      maxAge: 60 * 60 * 24,
      httpOnly: true,
      sameSite: 'strict',
    })
    return Response.json(
      { error: 'This service requires users to be 13 or older.' },
      { status: 403 }
    )
  }
  // ... account creation
}

If you intend to support child accounts via parental consent, implement the two-stage pending-consent flow described in the verifiable-consent check instead of hard-blocking.

• ID: coppa-compliance.age-determination.underage-blocking

• Severity: high

• What to look for: Count all relevant instances and enumerate each. Trace the code path that executes when a user enters a date of birth that makes them under 13. Does the code route them to a COPPA-compliant flow (parental consent workflow) or block them entirely? Check the server-side handler: does it return an error and refuse to create an account, or does it silently continue? If the application is designed to support child accounts with parental consent, look for a staging flow: a pending account state, a parent email collection step, and a block on the child's access until consent is confirmed. If the application is adults-only, verify that under-13 users are hard-blocked with a clear, non-alarmist message — not just redirected to a marketing page. Look for whether the block is persisted (session/cookie noting that access was denied) or whether a user can simply reload and try a different birth date.

• Pass criteria: When a user identifies as under 13, one of two things happens: (1) The user is hard-blocked with a clear message that the service requires users to be 13 or older, and no account or data is created. Or (2) The user is routed to a COPPA-compliant experience that includes a verifiable parental consent flow before any account data is stored. In either case, the block or routing is enforced server-side and not bypassable by resubmitting the form with different data (e.g., rate limiting, session state). A partial or placeholder implementation does not count as pass.

• Fail criteria: Under-13 users receive a warning message in the UI but account creation proceeds server-side anyway. The block exists client-side only and is bypassed by disabling JavaScript or altering the form submission. The under-13 path silently redirects to the homepage with no explanation and no block on re-registration attempts.

• Skip (N/A) when: No age gate exists (in which case the age-gate-present check already fails).

• Detail on fail: Example: "Age gate component shows an error for under-13 users in the UI, but the POST /api/auth/register endpoint does not validate the dateOfBirth field and creates the account regardless." or "Under-13 users are redirected to the homepage but no server-side flag prevents them from re-registering with a different birth date.".

• Remediation: Implement a hard block on the server side and optionally a session flag to reduce re-registration attempts:

  // app/api/auth/signup/route.ts
  import { cookies } from 'next/headers'
  
  export async function POST(req: Request) {
    const { email, password, dateOfBirth } = await req.json()
  
    const birth = new Date(dateOfBirth)
    const now = new Date()
    const ageMs = now.getTime() - birth.getTime()
    const ageYears = ageMs / (1000 * 60 * 60 * 24 * 365.25)
  
    if (ageYears < 13) {
      // Set a short-lived cookie to prevent immediate retry
      cookies().set('age_blocked', '1', {
        maxAge: 60 * 60 * 24, // 24 hours
        httpOnly: true,
        sameSite: 'strict',
      })
  
      // Return 403 — do NOT store email or any submitted data
      return Response.json(
        {
          error: 'This service is for users 13 and older. ' +
            'If you believe this is an error, please ask a parent or guardian to contact us.'
        },
        { status: 403 }
      )
    }
  
    // ... account creation for adults
  }
  

  If you want to support child accounts, see the verifiable-consent check for the parental consent flow.

• Cross-reference: For related patterns and deeper analysis, see the corresponding checks in other AuditBuffet audits covering this domain.