MaskMail — Private Temp Inbox by RatioWorks

MaskMail — Private Temp Inbox is a privacy-focused Firefox extension for creating and managing temporary email addresses without leaving your browser.
Create disposable inboxes in seconds, copy addresses instantly, receive messages, monitor unread mail, manage multiple active inboxes, and replace addresses when you no longer need them.
MaskMail supports Mail.tm and Mail.gw with automatic provider fallback and detailed diagnostics when a provider or mailbox session encounters a problem.
Optional Firefox Relay integration lets users connect their own Firefox Relay account and manage Relay masks from MaskMail. Relay remains a separate forwarding service from MaskMail's temporary inboxes. MaskMail is an independent project and is not affiliated with or endorsed by Mozilla.
Privacy-focused message reading
Email is displayed through a sanitized HTML reader designed to preserve useful formatting while blocking potentially unsafe or privacy-sensitive content. Scripts, forms, iframes, executable content, unsafe URLs, and other active elements are removed. Remote images are blocked by default and can be loaded manually when desired.
Key features include:
- Temporary addresses through Mail.tm and Mail.gw
- Automatic provider fallback
- Multiple active temporary inboxes
- Inbox naming and organization
- Unread-message notifications
- Automatic and manual inbox refresh
- Sanitized HTML email rendering
- Remote images blocked by default
- Supported image attachment previews
- Spam and mailbox search tools
- Domain and provider controls
- Local domain blocklist
- Optional Firefox Relay integration
- Relay Free/Premium-aware controls
- Privacy and provider diagnostics
- Address concealment
- Configurable local message-cache retention
- Responsive desktop, tablet, and mobile layouts
- Adjustable interface text size
- Reduced-motion accessibility option
- Keyboard and touch-friendly navigation
- Privacy, Terms, and provider-information pages