Resource Conflict

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This error occurs when the database rejects a write operation due to a conflict with existing data. The most common cause is violating a unique key constraint (e.g., trying to sign up with an email address or username that is already registered).

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Error Response Example (RFC 9457)

{
  "type": "https://docs.apinow.app/errors/conflict",
  "title": "Resource Conflict",
  "status": 409,
  "code": "RESOURCE_CONFLICT",
  "detail": "A record with the email 'alice@example.com' already exists.",
  "instance": "/api/v1/users"
}

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Troubleshooting Guide

For API Consumers (What it means & how to fix)

• Duplicate Data: You are attempting to write a value that must be unique but already exists in the system. Check the detail message to see which field is conflicted, and use a different value or update the existing record instead of creating a duplicate.

For API Authors (Domain & API Modeler notes)

• Unique Constraints: In the Domain Modeler, check which properties have the “Unique” attribute enabled, or have semantics that enforce uniqueness (such as Username or Email).