Email already in use

ERR-P01-IDT-3100 - Email already in use

Summary

POST /v1/humans was called with an email that already has a row.

When this is raised

• A human row already exists for the (normalised, lowercased) email on POST /v1/humans, which is fresh-email-only.
• Re-mailing a code to an existing row is a different operation: POST /v1/humans/rotate handles both pending and active rows and is oracle-safe (always 202).

What to do

• To re-trigger verification for an existing email, call POST /v1/humans/rotate instead of POST /v1/humans.
• If you did not expect the email to exist, it was registered earlier; use the rotate + verify flow to obtain a fresh API-Key.

Server-side cause

• Raised by: packages/identity/src/service/human.ts - startCreate.
• Guard: if (existing[0]) throw new HumanError('email_already_in_use', …); mapped to IDENTITY_ERR.human_email_already_in_use (409) in packages/identity/src/router/humans.ts.

Example response

{
  "type":      "https://citizenry.id/errors/ERR-P01-IDT-3100",
  "title":     "Conflict",
  "status":    409,
  "code":      "ERR-P01-IDT-3100",
  "message":   "a row for this email already exists",
  "method":    "POST",
  "instance":  "/v1/humans",
  "request_url": "https://api.citizenry.id/v1/humans",
  "timestamp": "2026-05-17T07:00:00.000Z"
}

Related codes

• ERR-P01-IDT-2004 - email domain not allowed.
• ERR-P01-IDT-1100 - verification code invalid.

Changelog

• 0.1.0 - introduced.