# Facebook 1send is built ground up to be compliant with Meta's messaging rules. Meta enforces constraints on 3rd party solution providers to protect the Facebook user experience and **protect users from spam**. ### 24-hour message rule (Standard Messaging Window) Meta's traditional policy is the 24-hour rule, also known as the standard messaging window. After 24 hours have passed **since a contact’s last interaction with a Facebook Page**, the Facebook Page is no longer allowed to send them messages. Because of this restriction, most messaging solutions available are focused on customer service tasks. For example, a user can initiate a conversation with the Facebook Page asking for more details on a product or sale, which starts the 24-hours window to respond. Therefore it was previously impossible for a Facebook Page to reach out to a user outside of the 24-hours and remain compliant with Meta's policies. ### 1send Messenger Subscriptions Messenger subscriptions are the newest guidelines Meta released to enable businesses to message customers outside of the 24-hour rule, which is what 1send is built on. A Facebook Page can now initiate the conversation. Shifting the use case to sending promotional messages instead of customer service messages. Consistent with the 24-hour rule, **Meta does enforce constraints for Messenger subscriptions**. 1. **Consent required to message**. The Facebook user must provide an explicit opt-in before the business can send them messages. This is similar to SMS/email marketing consent requirements. 1send streamlines this with subscription URL links. 2. **One message per day.** Each Facebook user can only be sent a messaged once per day as a Messenger subscription. However, if they respond back then the 24 hour rule is effect and the business can freely reply. In practice, constraints like explicit opt-in ends up benefitting the Facebook Page since users that knowingly and willingly consent to receiving your messages are also more likely to convert because subscribing signals intent. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.1send.net/learn/facebook.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.