# TaxSessionsPublicController_TransactionValidationErrors

Returns grouped transaction validation errors for the specified tax session.

`GET /api/v1/TaxSessions/TransactionValidationErrors`

**API:** Excise Platform API
**Tag:** Tax Sessions
**API Version:** v1
**Base URL:** https://excise.avalara.com
**Accepts:** `application/json`
**Authentication:** Basic (username + license key)

Source: https://developer.avalara.com/products/excise/api/methods/Tax%20Sessions/TaxSessionsPublicController_TransactionValidationErrors/

## Description

Returns transaction-level validation errors grouped by schedule and rule for the specified
tax session. These are distinct from return-level errors (ReturnErrors) and represent issues
found in individual schedule transactions during validation.

## Parameters

| Name | Type | In | Required | Description |
|---|---|---|---|---|
| `x-company-id` | integer | header | Yes | Company ID that owns the data. |
| `X-Avalara-Client` | string | header | No | Identifies the software you are using to call this API. For more information on the client header, see Client Headers. |
| `headerId` | integer | query | Yes | The header id of the specified tax session. |
| `sequence` | integer | query | No | The sequence (Default: highest sequence for the HeaderId). |
| `scheduleCode` | string | query | No | Optional filter by schedule code. |
| `ruleId` | integer | query | No | Optional filter by validation rule id. |
| `errorLevelInd` | string | query | No | Optional filter by error level (C, W, I). |

## Responses

| Status | Description | Schema |
|---|---|---|
| 200 | Returns the list of transaction validation errors. | `Avalara.Excise.Common.Contracts.Services.RestTaxSessionTransactionValidationErrorsResponse` |
| 400 | The HeaderId is invalid or not associated with the specified company. |  |
| 401 | Authentication credentials are incorrect. |  |

### 200 Response: `Avalara.Excise.Common.Contracts.Services.RestTaxSessionTransactionValidationErrorsResponse`

Response returned by the Tax Sessions TransactionValidationErrors endpoint,
containing grouped transaction-level validation errors.

| Property | Type | Required | Description |
|---|---|---|---|
| `HeaderId` | integer | No | The unique header identifier. Example: `12345`. |
| `Sequence` | number | No | The sequence number that was queried. Example: `0`. |
| `Errors` | Avalara.Excise.Common.Contracts.Services.RestTransactionValidationErrorItem[] | No | Grouped transaction validation errors. |

## Example Request

```bash
curl -X GET "https://excise.avalara.com/api/v1/TaxSessions/TransactionValidationErrors" \
  -H "Authorization: Basic <credentials>" \
  -H "Accept: application/json"
```