Firefox Relay is Mozilla's email masking service that creates aliases forwarding to your real inbox. The free tier gives you 5 aliases with a 150KB size...
Aspect
Temporary Email Services
Firefox Relay
Account and Setup
No account needed. Open the site, get an address instantly. No browser requirement, no extension to install. Works on any device with a web browser, including shared computers and mobile devices where you would not want to install extensions.
Requires a Mozilla account and the Firefox browser (or the Relay extension). Setup takes a few minutes. The extension auto-fills aliases on signup forms, which makes ongoing use smooth once the initial setup is complete.
Free Tier Limits
Unlimited addresses, unlimited use. Some services limit inbox duration but not the number of addresses you can create. NukeMail, for example, gives you 24 hours per address with no cap on how many addresses you generate.
Only 5 aliases on the free tier. Once you use all 5, you either delete one or pay $1.99/month for unlimited aliases. Five aliases run out fast if you use them for every new signup. Deleting an alias to make room means losing access to any service using that alias.
Email Size
Most temp email services accept emails up to 10-25MB, which covers virtually all verification emails, receipts, and confirmations. NukeMail accepts emails up to 25MB, matching Gmail's maximum outbound limit.
Free tier has a 150KB limit per email. This is extremely small — many HTML emails with images exceed this. Emails over the limit are silently dropped with no notification to the sender or recipient. The paid tier raises this to 10MB, which is adequate for most purposes.
Trust and Privacy Policy
Varies wildly by provider. Some temp email services are ad-heavy and have questionable privacy practices. Others like NukeMail are clean and transparent. You need to evaluate each one individually based on their privacy policy and reputation.
Mozilla is a well-known nonprofit with a strong track record on privacy. Their privacy policy is clear and they have no financial incentive to misuse your data. This is a genuine advantage that few other services can match. Mozilla is also subject to strong accountability as a public-benefit organization.
Address Permanence
Addresses expire after a set time. Not suitable for accounts you want to keep long-term. However, the temporary nature is the core feature — it prevents addresses from accumulating in databases where they could be breached or sold.
Aliases persist indefinitely. You can use them for long-lived accounts and disable them later if spam becomes a problem. This permanence makes Relay suitable for services you want to use for months or years.
Browser Integration
Works in any browser. Copy-paste the address manually. No special integration needed. This cross-browser compatibility means it works on Chrome, Edge, Safari, and any other browser, not just Firefox.
Tight integration with Firefox. The extension detects email fields and offers to generate an alias with one click. Very smooth workflow if you already use Firefox. However, if you use Chrome or Safari as your primary browser, this integration advantage disappears.
Reply Support
Receive-only. Cannot reply through the temp address. This limits temp email to scenarios where one-way receipt is sufficient, like verification codes and confirmation links.
Supports replies through the alias on the paid tier. Free tier does not support replies. The paid reply feature makes Relay aliases functionally equivalent to separate email accounts for two-way communication.
Want to test this yourself? Create a free NukeMail inbox in 5 seconds.Try It Free →
Verdict
Firefox Relay is a solid choice if you already use Firefox and trust Mozilla. The browser integration is convenient, and Mozilla's privacy credentials are strong. However, the free tier is genuinely restrictive — 5 aliases with a 150KB size limit means you will hit walls quickly.
Temporary email is better for high-volume, quick disposable use. Need to sign up for 20 things today? Temp email handles that without hitting any limit. Need an address for 5 minutes to grab a verification code? Temp email is faster than setting up a Relay alias.
If you want persistent aliases from a trustworthy provider and are willing to pay $1.99/month, Firefox Relay Premium is worth considering. For anonymous, disposable, no-account-needed use, temp email remains the faster and more flexible option.
A practical approach is to use Firefox Relay for the five or so services you consider most important for ongoing privacy, and temp email for everything else. This way you get the best of both: Mozilla's trustworthy aliases for your key accounts and unlimited disposable addresses for throwaway signups.
The 150KB email size limit on Firefox Relay's free tier is worth emphasizing because it causes real problems. Many verification emails from services like banks and e-commerce sites exceed 150KB due to embedded images and HTML formatting. When these are silently dropped, you are left wondering why the verification email never arrived — with no error message or indication that the size limit was the issue.
