# Receiving Messages The **Relay SDK** allows your users to receive messages even when their device is offline. Postboxes created in the Relay receive messages via HTTP POST to a unique endpoint. The body of the POST request is stored in the postbox. No headers or encoding information is saved. The endpoint associated with each postbox is accessible via the return value from `createPostbox` or `listPostboxes` and should be shared with the peer wishing to send messages to the user. The peer must then POST a message to the endpoint and it will be stored in the postbox. {% hint style="info" %} Note that the message payload will be stored as provided, without any encryption. Clients should ensure that their message is encrypted appropriately before POSTing. {% endhint %} --- # 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.sudoplatform.com/guides/decentralized-identity/decentralized-identity/relay-sdk/receiving-messages.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.