# Create an environment variable

**POST** `/v1/environment-variables`

⚠️ Experimental endpoint: this API is in active development and may change at any time without notice. ⚠️

Creates a new environment variable in a project's `production` or `preview` environment, or a preview branch override when `branchId` is supplied. Returns 409 if a variable with the same key already exists in that scope — use PATCH to replace its value. Values are stored encrypted and are not returned by subsequent reads.

Base URL: `https://api.prisma.io`

Tags: `[Experimental]`

## Authorization

Any ONE of the following options authorizes this operation; every scheme listed within an option is required together.

| Option | Scheme | Type | Sent as | Scopes |
| --- | --- | --- | --- | --- |
| Option 1 | `OAuth2` | `oauth2` | `Authorization: Bearer <access token>` | `offline_access`, `workspace:admin` |
| Option 2 | `Bearer` | `http` | `Authorization: Bearer <token>` (JWT) | — |

### OAuth 2.0 flows

- **OAuth2 · authorizationCode**
  - Authorization URL: `https://auth.prisma.io/authorize`
  - Token URL: `https://auth.prisma.io/token`
  - Refresh URL: `https://auth.prisma.io/token`
  - Scope `offline_access` — Offline access
  - Scope `workspace:admin` — Full access to workspace resources

## Request body

Optional. Media type: `application/json`

### Example request body

```json
{
  "branchId": "string",
  "class": "preview",
  "key": "string",
  "projectId": "string",
  "value": "string"
}
```

## Responses

| Status | Description | Media type |
| --- | --- | --- |
| `201` | Variable created. | `application/json` |
| `401` | Missing or invalid authorization token. | `application/json` |
| `404` | Project not found, or token does not have access to it. | `application/json` |
| `409` | A variable with this key already exists in this environment. | `application/json` |
| `422` | Invalid request. | `application/json` |
| `500` | Internal error while processing the encrypted variable (e.g., a master-key rotation or deploy issue prevents the project's wrapped DEK from being decrypted). Not a client-fixable condition. | `application/json` |

### Example response: 201 — Variable created.

```json
{
  "data": {
    "branchId": "string",
    "class": "preview",
    "createdAt": "2026-06-09T00:00:00Z",
    "id": "string",
    "isManagedBySystem": true,
    "key": "string",
    "projectId": "string",
    "type": "environment-variable",
    "updatedAt": "2026-06-09T00:00:00Z",
    "url": "https://example.com",
    "valueKid": "string"
  }
}
```

### Example response: 401 — Missing or invalid authorization token.

```json
{
  "error": {
    "code": "string",
    "hint": "string",
    "message": "string"
  }
}
```

### Example response: 404 — Project not found, or token does not have access to it.

```json
{
  "error": {
    "code": "string",
    "hint": "string",
    "message": "string"
  }
}
```

### Example response: 409 — A variable with this key already exists in this environment.

```json
{
  "error": {
    "code": "string",
    "hint": "string",
    "message": "string"
  }
}
```

### Example response: 422 — Invalid request.

```json
{
  "error": {
    "code": "string",
    "hint": "string",
    "message": "string"
  }
}
```

### Example response: 500 — Internal error while processing the encrypted variable (e.g., a master-key rotation or deploy issue prevents the project's wrapped DEK from being decrypted). Not a client-fixable condition.

```json
{
  "error": {
    "code": "string",
    "hint": "string",
    "message": "string"
  }
}
```

## Related pages

- [[Experimental]](./tags/experimental.md)
- [Acquire Alchemy deploy lease](./postv1projectsbyprojectidbranchesbybranchidalchemy-statelease.md)
- [Agents](./tags/agents.md)
- [Alchemy state store version](./getv1projectsbyprojectidbranchesbybranchidalchemy-stateversion.md)
- [Buckets](./tags/buckets.md)
- [Connections](./tags/connections.md)
- [Create a branch](./postv1projectsbyprojectidbranches.md)
- [Create a custom domain](./postv1appsbyappiddomains.md)
- [Create a custom domain](./postv1servicesbyserviceiddomains.md)
- [Create a workspace](./postv1workspaces.md)

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