# Get Branch

## API Name

API Name: Branch – Get

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## Overview

This API retrieves the details of a specific branch within a given project.

MBSE Core uses this API to:

* Validate branch existence
* Retrieve branch metadata
* Support branch-based synchronization

Connector responsibility:

* Retrieve the branch identified by `branchId` within the specified `projectId`
* Return branch details in key-value format
* If the branch does not exist, return HTTP `404 Not Found`

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### API URI

```bash
GET: /mbse/api/1.0/branches/{branchId}
    ?projectId={projectId}
```

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### Path Parameters

| Name     | Mandatory | Type   | Description                   |
| -------- | --------- | ------ | ----------------------------- |
| branchId | True      | String | ID of the branch to retrieve. |

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### URI Parameters

| Name      | Mandatory | Type   | Description                                   |
| --------- | --------- | ------ | --------------------------------------------- |
| projectId | True      | String | ID of the project in which the branch exists. |

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### Behavior Rules

1. The API must retrieve the branch within the context of the given project.
2. If the branch exists:
   * Return branch details.
3. If the branch does not exist:
   * Return HTTP `404 Not Found`.
4. The response must not return unrelated branch data.
5. Branch lookup must be project-scoped.

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### Response Payload

#### Sample Response

```json
{
  "branchId": "main",
  "branchName": "Main Branch"
}
```

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### Response Parameters

| Name       | Required | Type   | Description                      |
| ---------- | -------- | ------ | -------------------------------- |
| branchId   | True     | String | Unique identifier of the branch. |
| branchName | True     | String | Display name of the branch.      |

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### Error Handling

| HTTP Status | Description                                |
| ----------- | ------------------------------------------ |
| 404         | Branch not found in the specified project. |
| 400         | Invalid input parameters.                  |

***

### Example Use Case

#### Get Branch Details

```bash
GET /mbse/api/1.0/branches/main?
projectId=123
```

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### Implementation Guidelines

* Connector must ensure branch lookup is scoped to the provided `projectId`.
* Branch identifiers must be unique within a project.
* Do not return null response for non-existing branch — explicitly return HTTP `404`.

***

### Design Rationale

This API provides:

* Strict branch validation
* Clear project scoping
* Deterministic behavior for multi-branch systems

It ensures branch-level