> For the complete documentation index, see [llms.txt](https://docs.1send.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.1send.net/learn/facebook.md).

# 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.