---
title: Mailbox capabilities and limits
description: Understand the capabilities and limits of Scaleway Mailbox.
tags: mailbox-capabilities
dates:
  validation: 2026-03-20
  posted: 2026-03-20
---

This page provides information about the capabilities and limits of Scaleway Mailbox.

## Mailbox quotas

- Mailbox storage: up to 20 GB per mailbox (for emails, attachments, and mailbox folders).
- Number of Mailboxes: 20 Mailbox email accounts per project (during Beta phase). If you need to create more mailboxes, contact the [Scaleway Support team](https://console.scaleway.com/support/tickets/create?for=product&productName=mailbox).

## Message limits

- `message` (the maximum number of messages that can be submitted per SMTP session): 10
- `size` (the maximum size of a message): 104857600 bytes (100 MiB)
- `received-headers` (the maximum number of received headers that a message can contain): 50

## Supported ESMTP extensions

Mailbox SMTP relay supports the following [ESMTP extensions](https://www.iana.org/assignments/mail-parameters/mail-parameters.txt):

- 8BITMIME
- BINARYMIME
- CHUNKING
- ENHANCEDSTATUSCODES
- NO-SOLICITING
- PIPELINING
- REQUIRETLS
- SIZE 104857600
- SMTPUTF8
- STARTTLS