import ApiRequest from '@site/src/components/ApiRequest'
:::info Placeholders
Placeholders in the code samples below are delimited by angle brackets (i.e. `<placeholder-name>`). You will need to replace them with the values that are correct in _your_ situation for the code samples to run properly.
In this guide we'll schedule a feature for release at some point in time. The exact same logic applies if you want to make a feature available until some point in the future. Finally, if you want to only make a feature available during a limited time period, you can easily combine the two options.
[Strategy constraints](../reference/strategy-constraints.md#date-and-time-operators) are the easiest way to schedule feature releases ([as long as your SDKs are up to date](../reference/strategy-constraints.md#incompatibilities)). You can use this approach with _any_ strategy you want. The strategies will work just as they normally do, they just won't become active until the specified time. For example: with the standard strategy, the feature would become available to all your users at the specified time; with a gradual rollout, the rollout would start at the specified time.
3. Add a date-based constraint by selecting the `currentTime` context field (step 1 in the below image), choosing the `DATE_AFTER` operator (step 2), and setting the point in time where you want the feature to be available from (step 3)
![A strategy constraint specifying that the activation strategy should be enabled at 12:00 AM, November 25th 2022. There are visual call-outs pointing to the relevant settings mentioned above.](/img/strategy-constraint-date-after.png)
To add an activation strategy via the Admin API, use the feature's `strategies` endpoint to add a new strategy (see the [API documentation for adding strategies to feature flags](/reference/api/legacy/unleash/admin/features-v2.md#add-strategy) for more details).
The payload's `"name"` property should contain the name of the strategy to apply (see [activation strategies reference documentation](../reference/activation-strategies.md) for all built-in strategies' _modeling names_).
The `"constraint"` object should have the same format as described in the code sample below. The activation date must be in an [RFC 3339-compatible format](https://datatracker.ietf.org/doc/html/rfc3339#section-5.8), e.g. `"1990-12-31T23:59:60Z"`.
}} url="api/admin/projects/<project-id>/features/environments/<environment>/strategies" title="Add a feature activation strategy with a scheduled activation time."/>
The `"operator"` property in the code sample can be replaced with [any of the other date and time-based operators](../reference/strategy-constraints.md#date-and-time-operators) according to your needs.
To schedule feature releases without using strategy constraints, you can use custom activation strategies. This requires defining a custom strategy and then implementing that strategy in your SDKs. For detailed instructions on how to do either of these things, refer to their respective how-to guides:
- [How to _define_ custom strategies](../how-to/how-to-use-custom-strategies.md#step-1)
- [How to _implement_ custom strategies](../how-to/how-to-use-custom-strategies.md#step-3)
### Step 1: Define and apply a custom activation strategy
**Define a strategy** that takes a parameter that tells it when to activate (visit [the custom activation strategy reference documentation](../reference/custom-activation-strategies.md#definition) for full details on definitions):
2. Give the strategy a required string parameter where the user can enter the time at which the feature should activate. Be sure to describe the format that the user must adhere to.
![A custom activation strategy definition for a strategy called `enableAfter`. It takes a required parameter called `start time`: a string in a date format.](/img/custom-strategy-enable-after.png)
In each of the client SDKs that will interact with your feature, implement the strategy ([the implementation how-to guide](../how-to/how-to-use-custom-strategies.md#step-3) has steps for all SDK types).