> ## Documentation Index
> Fetch the complete documentation index at: https://docs.y.uno/llms.txt
> Use this file to discover all available pages before exploring further.

# Error Codes

> Complete error code reference table for Sellers API.

## Seller CRUD Errors

| HTTP Status        | Error Code                         | Description                                                       |
| :----------------- | :--------------------------------- | :---------------------------------------------------------------- |
| `400 Bad Request`  | `DUPLICATE_PROVIDER_MAPPING`       | Duplicate `(provider.id, payment_method_type)` combination found. |
| `400 Bad Request`  | `VALIDATION_ERROR`                 | Request body fails validation.                                    |
| `400 Bad Request`  | `INVALID_PROVIDER`                 | The provider `id` is not valid.                                   |
| `401 Unauthorized` | —                                  | Invalid or missing API keys.                                      |
| `403 Forbidden`    | `FORBIDDEN`                        | Account not found or unauthorized.                                |
| `404 Not Found`    | `FRANCHISE_MAPPING_NOT_FOUND`      | No seller mapping exists for the given ID.                        |
| `409 Conflict`     | `FRANCHISE_MAPPING_ALREADY_EXISTS` | mapping with this `merchant_seller_id` already exists.            |

## Payment Request Errors

| HTTP Status       | Error Code                            | Description                                                   |
| :---------------- | :------------------------------------ | :------------------------------------------------------------ |
| `400 Bad Request` | `MUTUALLY_EXCLUSIVE_SELLER_REFERENCE` | Both `seller_id` and `merchant_seller_id` were sent together. |

## Franchise Resolution (Non-Blocking)

These scenarios do **not** return errors to the merchant. The payment always proceeds:

| Scenario                                               | Behavior                                                          |
| :----------------------------------------------------- | :---------------------------------------------------------------- |
| Mapping found for routed provider                      | Payment uses the resolved `merchant_id` and type-specific detail. |
| No mapping for routed provider / `payment_method_type` | Warning logged, original `merchant_id` from connection used.      |
| No `payment_method` data for this seller               | Warning logged, original `merchant_id` from connection used.      |
| Franchise resolution service unavailable               | Error logged, original `merchant_id` from connection used.        |
| Neither `seller_id` nor `merchant_seller_id` present   | Franchise resolution skipped entirely — no impact.                |