Frequently Asked Questions

Where are my email attachments?

Email attachments are not viewable for public addresses from the Website. Attachments must be downloaded using REST API.

Attachments on emails sent to Enhanced Addresses can be viewed in the Unified Inbox or in an email client using POP3.

Read more about email attachments at Mailsac.

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:

  • as a developer, to test that your application is sending email

  • 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

Why weren’t my messages received?

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

The Missing Email 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. The max message size is 2.5MB

  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 6 messages per inbox.

Message storage prevents emails from being recycled.

  1. If you star a message, it will not be recycled until you unstar it.

  2. Messages in enhanced 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 enhanced addresses or custom domains. Responses can be sent from non-mailsac accounts you have configured your email client to use.

When does Ops/Operations/API Call Usage Reset?

Ops (Operations) Usage usage resets on the first of the Month UTC.

How can my team members see email in our private domain?

For plans that support multiple API keys. You can create API keys for your team members. These name API keys can be used for API access and website authentication.

Where Can I Ask a Question About Mailsac?

The Mailsac Forum is available to all customers, on both free and paid plans. Questions asked of our sales and support staff are often answered on the forums.