> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.getunleash.io/api/add-milestone-to-release-template/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.getunleash.io/_mcp/server.

# Add a milestone

POST https://app.unleash-instance.example.com/api/admin/release-plan-templates/{templateId}/milestones

**Enterprise feature**

Finds release template identified by its id and adds a milestone

Reference: https://docs.getunleash.io/api/add-milestone-to-release-template

## Authentication

- `Authorization` header (required) — API key needed to access this API
- `Authorization` header (bearer token, required) — API key needed to access this API, in Bearer token format

## Request

### Path parameters

- `templateId` (string, required)

## Response

### 200

#/components/schemas/releasePlanMilestoneSchema

- `id` (string, required) — The milestone's ID. Milestone IDs are ulids.
- `name` (string, required) — The name of the milestone.
- `sortOrder` (integer, required) — The order of the milestone in the release plan.
- `releasePlanDefinitionId` (string, required) — The ID of the release plan/template that this milestone belongs to.
- `startedAt` (string, optional, nullable) — The date and time when the milestone was started.
- `transitionCondition` (ReleasePlanMilestoneSchemaTransitionCondition, optional, nullable) — The condition configuration for the transition.
- `progressionExecutedAt` (string, optional, nullable) — The date and time when the milestone progression was executed.
- `pausedAt` (string, optional, nullable) — The date and time when the milestone was paused.
- `strategies` (list of releasePlanMilestoneStrategySchema, optional) — A list of strategies that are attached to this milestone.

## Errors

### 401 Unauthorized Error

Authorization information is missing or invalid. Provide a valid API token as the `authorization` header, e.g. `authorization:*.*.my-admin-token`.

- `id` (string, optional) — The ID of the error instance
- `name` (string, optional) — The name of the error kind
- `message` (string, optional) — A description of what went wrong.

### 403 Forbidden Error

The provided user credentials are valid, but the user does not have the necessary permissions to perform this operation

- `id` (string, optional) — The ID of the error instance
- `name` (string, optional) — The name of the error kind
- `message` (string, optional) — A description of what went wrong.

### 404 Not Found Error

The requested resource was not found.

- `id` (string, optional) — The ID of the error instance
- `name` (string, optional) — The name of the error kind
- `message` (string, optional) — A description of what went wrong.

## Types

### ReleasePlanMilestoneSchemaTransitionCondition

The condition configuration for the transition.

### releasePlanMilestoneStrategySchema

Schema representing the creation of a release plan milestone strategy.

- `id` (string, required) — The milestone strategy's ID. Milestone strategy IDs are ulids.
- `milestoneId` (string, required) — The ID of the milestone that this strategy belongs to.
- `sortOrder` (double, required) — The order of the strategy in the list
- `name` (string, required) — The name of the strategy type
- `strategyName` (string, required, deprecated) — The name of the strategy type
- `title` (string, optional, nullable) — A descriptive title for the strategy
- `parameters` (map from string to string, optional) — An object containing the parameters for the strategy
- `constraints` (list of constraintSchema, optional) — A list of the constraints attached to the strategy. See https://docs.getunleash.io/concepts/activation-strategies#constraints
- `variants` (list of createStrategyVariantSchema, optional) — Strategy level variants
- `segments` (list of double, optional) — Ids of segments to use for this strategy
- `disabled` (boolean, optional, nullable) — A toggle to disable the strategy. defaults to false. Disabled strategies are not evaluated or returned to the SDKs

### constraintSchema

A strategy constraint. For more information, refer to [the strategy constraint reference documentation](https://docs.getunleash.io/concepts/activation-strategies#constraints)

- `contextName` (string, required) — The name of the context field that this constraint should apply to.
- `operator` (enum, required) — The operator to use when evaluating this constraint. For more information about the various operators, refer to [the strategy constraint operator documentation](https://docs.getunleash.io/concepts/activation-strategies#constraint-operators).
  - Allowed values: `NOT_IN`, `IN`, `STR_ENDS_WITH`, `STR_STARTS_WITH`, `STR_CONTAINS`, `NUM_EQ`, `NUM_GT`, `NUM_GTE`, `NUM_LT`, `NUM_LTE`, `DATE_AFTER`, `DATE_BEFORE`, `SEMVER_EQ`, `SEMVER_GT`, `SEMVER_LT`, `SEMVER_GTE`, `SEMVER_LTE`, `REGEX`
- `caseInsensitive` (boolean, optional, default: false) — Whether the operator should be case sensitive or not. Defaults to `false` (being case sensitive).
- `inverted` (boolean, optional, default: false) — Whether the result should be negated or not. If `true`, will turn a `true` result into a `false` result and vice versa.
- `values` (list of string, optional) — The context values that should be used for constraint evaluation. Use this property instead of `value` for properties that accept multiple values.
- `value` (string, optional) — The context value that should be used for constraint evaluation. Use this property instead of `values` for properties that only accept single values.

### createStrategyVariantSchema

This is an experimental property. It may change or be removed as we work on it. Please don't depend on it yet. A strategy variant allows you to attach any data to strategies instead of only returning `true`/`false`. Strategy variants take precedence over feature variants.

- `name` (string, required) — The variant name. Must be unique for this feature flag
- `weight` (integer, required) — The weight is the likelihood of any one user getting this variant. It is an integer between 0 and 1000. See the section on [variant weights](https://docs.getunleash.io/concepts/feature-flag-variants#variant-weight) for more information
- `weightType` (enum, required) — Set to `fix` if this variant must have exactly the weight allocated to it. If the type is `variable`, the weight will adjust so that the total weight of all variants adds up to 1000. Refer to the [variant weight documentation](https://docs.getunleash.io/concepts/feature-flag-variants#variant-weight).
  - Allowed values: `variable`, `fix`
- `stickiness` (string, required) — The [stickiness](https://docs.getunleash.io/concepts/feature-flag-variants#variant-stickiness) to use for distribution of this variant. Stickiness is how Unleash guarantees that the same user gets the same variant every time
- `payload` (CreateStrategyVariantSchemaPayload, optional) — Extra data configured for this variant

### CreateStrategyVariantSchemaPayload

Extra data configured for this variant

- `type` (enum, required) — The type of the value. Commonly used types are string, number, json and csv.
  - Allowed values: `json`, `csv`, `string`, `number`
- `value` (string, required) — The actual value of payload

## Examples

**Response**

```json
{
  "id": "01JB9GGTGQYEQ9D40R17T3YVW1",
  "name": "My milestone",
  "sortOrder": 1,
  "releasePlanDefinitionId": "01JB9GGTGQYEQ9D40R17T3YVW2",
  "startedAt": "2024-01-01T00:00:00.000Z",
  "transitionCondition": {},
  "progressionExecutedAt": "2024-01-01T00:00:00.000Z",
  "pausedAt": "2024-01-01T00:00:00.000Z",
  "strategies": [
    {
      "id": "01JB9GGTGQYEQ9D40R17T3YVW3",
      "milestoneId": "01JB9GGTGQYEQ9D40R17T3YVW1",
      "sortOrder": 9999,
      "name": "flexibleRollout",
      "strategyName": "flexibleRollout",
      "title": "Gradual Rollout 25-Prod",
      "parameters": {
        "groupId": "some_new",
        "rollout": "25",
        "stickiness": "sessionId"
      },
      "constraints": [
        {
          "contextName": "appName",
          "operator": "IN",
          "caseInsensitive": false,
          "inverted": false,
          "values": [
            "1",
            "2"
          ]
        }
      ],
      "variants": [
        {
          "name": "blue_group",
          "weight": 1,
          "weightType": "fix",
          "stickiness": "custom.context.field",
          "payload": {
            "type": "json",
            "value": "{\"color\": \"red\"}"
          }
        }
      ],
      "segments": [
        1,
        2
      ],
      "disabled": false
    }
  ]
}
```

**SDK Code**

```python
import requests

url = "https://app.unleash-instance.example.com/api/admin/release-plan-templates/templateId/milestones"

headers = {"Authorization": "<apiKey>"}

response = requests.post(url, headers=headers)

print(response.json())
```

```javascript
const url = 'https://app.unleash-instance.example.com/api/admin/release-plan-templates/templateId/milestones';
const options = {method: 'POST', headers: {Authorization: '<apiKey>'}};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go
package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://app.unleash-instance.example.com/api/admin/release-plan-templates/templateId/milestones"

	req, _ := http.NewRequest("POST", url, nil)

	req.Header.Add("Authorization", "<apiKey>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby
require 'uri'
require 'net/http'

url = URI("https://app.unleash-instance.example.com/api/admin/release-plan-templates/templateId/milestones")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = '<apiKey>'

response = http.request(request)
puts response.read_body
```

```java
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.post("https://app.unleash-instance.example.com/api/admin/release-plan-templates/templateId/milestones")
  .header("Authorization", "<apiKey>")
  .asString();
```

```php
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('POST', 'https://app.unleash-instance.example.com/api/admin/release-plan-templates/templateId/milestones', [
  'headers' => [
    'Authorization' => '<apiKey>',
  ],
]);

echo $response->getBody();
```

```csharp
using RestSharp;

var client = new RestClient("https://app.unleash-instance.example.com/api/admin/release-plan-templates/templateId/milestones");
var request = new RestRequest(Method.POST);
request.AddHeader("Authorization", "<apiKey>");
IRestResponse response = client.Execute(request);
```

```swift
import Foundation

let headers = ["Authorization": "<apiKey>"]

let request = NSMutableURLRequest(url: NSURL(string: "https://app.unleash-instance.example.com/api/admin/release-plan-templates/templateId/milestones")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "POST"
request.allHTTPHeaderFields = headers

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```