> ## Documentation Index > Fetch the complete documentation index at: https://docs.getarca.app/llms.txt > Use this file to discover all available pages before exploring further. # Errors > Error responses returned by the Arca API. All error responses from the Arca API return JSON with a single `error` field describing the problem: ```json theme={null} { "error": "A description of the problem" } ``` ## HTTP status codes | Status | Name | When it occurs | | ------ | --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- | | `400` | Bad request | A required field is missing, a field is the wrong type, a value is out of the allowed range, or a date is in an invalid format. | | `401` | Unauthorized | The API key is missing, does not start with `arca_`, is not recognised, or has expired. | | `403` | Forbidden | Your API key lacks the required scope for this endpoint, or your workspace role does not permit the action (e.g. a viewer attempting to create a task). | | `404` | Not found | The requested resource does not exist, or it exists in a workspace you are not a member of. | | `500` | Internal server error | An unexpected error occurred on the server. | ## 400: Bad request Common causes and the exact error messages returned: | Error message | Cause | | ------------------------------------------------------------------------- | ------------------------------------------------------------------------------ | | `"workspace_id is required"` | `workspace_id` is missing or not a valid numeric string. | | `"name is required"` | `name` is missing or blank after trimming whitespace. | | `"title is required"` | `title` is missing or blank. | | `"title cannot be empty"` | A PATCH request set `title` to an empty string. | | `"folder_id is required"` | `folder_id` is missing when creating a list via the API. | | `"list_id is required"` | `list_id` is missing when creating a task via the API. | | `"status_id must be a valid numeric ID"` | `status_id` is not a valid integer. | | `"list_id must be a valid numeric ID"` | `list_id` is not a valid integer. | | `"Invalid priority. Must be one of: urgent, high, medium, low, none"` | `priority` is not one of the allowed values. | | `"Invalid due_date format. Use ISO 8601 UTC, e.g. 2026-03-18T17:00:00"` | `due_date` could not be parsed as a valid date. | | `"Invalid start_date format. Use ISO 8601 UTC, e.g. 2026-03-18T17:00:00"` | `start_date` could not be parsed as a valid date. | | `"content is required"` | Comment `content` is missing or blank. | | `"Invalid workspace ID"` | The `:id` path parameter in a workspace endpoint is not a valid integer. | | `"Invalid folder ID"` | The `:id` path parameter in a folder endpoint is not a valid integer. | | `"Invalid list ID"` | The `:id` path parameter in a list endpoint is not a valid integer. | | `"Invalid task ID"` | The `:id` path parameter in a task or comment endpoint is not a valid integer. | ## 401: Unauthorized | Error message | Cause | | ----------------------- | --------------------------------------------------------------------------------------------------- | | `"API key required"` | No `Authorization: Bearer arca_...` header or `X-API-Key` header was sent, or the format was wrong. | | `"Invalid API key"` | The key was provided but does not match any active key in the database. | | `"API key has expired"` | The key has passed its expiration date. Create a new key in **Settings → API Keys**. | ## 403: Forbidden | Error message | Cause | | --------------------------------------------- | --------------------------------------------------------------- | | `"Scope 'X' is required for this endpoint"` | Your API key was not granted the scope needed for this request. | | `"Viewers cannot create folders"` | Your workspace role is `viewer`. | | `"Viewers cannot edit folders"` | Your workspace role is `viewer`. | | `"Only owners and admins can delete folders"` | Your workspace role is `member` or `viewer`. | | `"Viewers cannot create lists"` | Your workspace role is `viewer`. | | `"Viewers cannot edit lists"` | Your workspace role is `viewer`. | | `"Only owners and admins can delete lists"` | Your workspace role is `member` or `viewer`. | | `"Viewers cannot create tasks"` | Your workspace role is `viewer`. | | `"Viewers cannot edit tasks"` | Your workspace role is `viewer`. | | `"Viewers cannot delete tasks"` | Your workspace role is `viewer`. | | `"Viewers cannot comment"` | Your workspace role is `viewer`. | | `"Access denied"` | You are not a member of the workspace the resource belongs to. | ## 404: Not found | Error message | Cause | | -------------------------------------- | --------------------------------------------------------------------------------------------- | | `"User not found"` | Returned by `GET /api/v1/me` if the user record no longer exists. | | `"Workspace not found"` | The workspace does not exist or you are not a member. | | `"Folder not found"` | The folder does not exist, or it belongs to a workspace you are not a member of. | | `"List not found"` | The list does not exist, or the given `folder_id` does not belong to the specified workspace. | | `"Task not found"` | The task does not exist. | | `"Status not found in this workspace"` | The `status_id` provided exists but belongs to a different workspace. | | `"List not found in this workspace"` | The `list_id` provided exists but belongs to a different workspace. |