Frequently Asked Questions

Where are my email attachments?

For private addresses, the Inbox App will allow you to download attachments. You can also fetch private messages with POP3 in your email client, such as Apple Mail or GMail.

Disposable emails under public email addresses disallow downloading attachments - you must download the entire message file, or fetch attachments programmatically using the API.

For private addresses, when using the Unified Inbox App, attachment files are downloadable.

Attachments cannot be hosted publicly for download because attachments often contain viruses and spam.

Why would I use Mailsac?

Any time you need a temporary email address, just make one

If you need to test your email system, send it to - even for a custom domain.

Other uses:

  • avoid spam by keeping your real email address private
  • create an account on a website without disclosing your real email address
  • give it out to strangers
  • use it as a shared email address
  • send mail to Mailsac for QA testing purposes
  • use it when you (legally) want to receive email without disclosing your identity
  • send to an email address or multiple email addresses without needing to create them
  • as a developer, to test that your application is sending email

Why weren’t my messages received?

There are many reasons messages may not be received or displayed by Mailsac.

The Missing Mail page provides detailed explanations about why messages are not received.

Most often, the following happens:

  1. The sender blocks traffic to disposable email providers like Mailsac. This is common with email signups or email verifications. People running websites do not want a bunch of spam accounts.
  2. Large message size. Mailsac only supports messages up to about 2 MB.
  3. Fast recycling. Without enough message storage, your inbound emails may be deleted quickly.
  4. Throttling. Non-paying customers can be throttled for sending too much. We are happy to lift this for paying customers. Custom Domain are not throttled.

The Mailsac Team is highly responsive to forum and support emails. Contact us and we will resolve your issue.

Can I use Mailsac for testing purposes?


We love to hear from developers that use Mailsac - contact us anytime.

Throttling may occur when sending. Avoid throttling by using a Custom Domain

How long is email saved?

Email messages that are sent to public domains ( ie are retained for 4 days and have a max number of messages per inbox of 6 days.

Message storage prevents emails from being recycled.

  1. If you star a message, it will not be recycled until you unstar it.
  2. Private addresses will not be recycled, up to your storage limit.
  3. Messages on custom domains will not be recycled, up to your storage limit.

Can other people see messages that I starred?

Nope. Only you can see them when you are logged in.

How do I reply to my Mailsac emails?

You must create an account to reply to emails. New accounts have 5 sending credits. Additional credits can be purchased <>_.

You can use POP3 to download messages on a private address or custom domain. Responses can be sent from non-mailsac accounts you have configured your email client to use.