Firefox Relay is Mozilla's email masking service. You create a mask, an address ending in mozmail.com, hand it out instead of your real address, and Relay forwards whatever arrives to the inbox you already use. The free tier gives you five masks, a browser extension that offers a fresh mask whenever a site asks for your email, and tracker removal on forwarded mail.
One disclosure before anything else: YeyMail, which publishes this blog, sells a competing alias service. Every claim below comes from Mozilla's own pages, checked on the date given, and we have tried to credit Relay where it deserves credit. Weigh our judgement accordingly.
Mozilla's name carries weight here, and it has earned it. This is the organisation behind Firefox, with a long public record of taking privacy seriously, and Relay mostly reflects that. Their FAQ commits to holding a forwarded email for no more than three days, and only when delivery has to be retried. As free products go, five masks with tracker removal and a tidy extension is genuinely useful.
But the ceiling arrives quickly, and the paid tier that lifts it is in a strange state. We loaded Mozilla's pages on 14 August 2026 to check every claim below, and the most important finding is not a feature at all: Relay Premium currently displays no price, and sign-up sits behind a waitlist.
What Relay does well
The core loop is pleasant. The extension notices email fields and offers to generate a mask on the spot, which removes the main friction of masking: remembering to do it. Masks forward to the inbox you already have, so there is no second mailbox to check and no migration to plan. If the general idea is new to you, our email masking explainer covers the mechanics.
Relay also benefits from where it sits. Masks are managed from the same Mozilla account used for Firefox itself, the extension is a first-party citizen in the browser rather than an afterthought, and for many people the whole experience amounts to clicking the suggestion in an email field and moving on.
Two things deserve specific credit. First, tracker removal is included on the free tier; Relay strips known email trackers from forwarded messages without asking you to pay for the privilege. Second, the documentation is unusually candid. The FAQ states plainly that forwarding has a 10 MB size limit and that larger emails are simply not forwarded, and that a message is stored for at most three days when it cannot be delivered straight away. Not every provider writes its limits down this clearly.
Five masks, and no way to reply
The free tier's two hard limits are the ones you will actually feel. The first is the cap: five masks in total. Five is enough to cover a newsletter address, a shopping address and a couple of experiments, but a mask-per-site habit, which is where the real protection lies, exhausts it in a week. The cap is also a planning problem, not just a volume one. Because five is so few, each mask ends up shared across many sites, and a shared mask cannot tell you which of those sites leaked or sold it.
The second is one-way traffic. On the free plan you can receive through a mask but not answer through it. Replying is a premium feature, and even there Mozilla's FAQ sets a window: premium subscribers can reply to a forwarded email only within three months of receiving it. If a seller asks a question about your delivery, or a support thread needs an answer, a free Relay mask leaves you choosing between silence and replying from your real address, which defeats the point. We've written about why the reply path matters more than most people expect.
Premium, as Mozilla's pages show it today
This is where a review written a few years ago would list a monthly price. We cannot, because Mozilla's pages do not show one. On the day we checked, both the Relay homepage and the dedicated premium page offered Join the Waitlist buttons for Premium, for phone masking and for the VPN bundle. The premium page notes that billing is monthly but attaches no figure. No checkout, no number.
The site does list countries where premium is described as available, from Austria through to the United States, so a purchase flow may exist for some visitors under some conditions. But what a would-be subscriber actually meets on the public pages is a waitlist, with no stated price and no stated timeline. If you are considering Relay specifically because you plan to pay for the unlimited tier, this is the single most important thing to know before you invest in the free tier's workflow: you may not currently be able to buy the upgrade at all.
For the record, here is what the premium tier promises, as listed on Mozilla's own pages, against what free offers today.
| Feature | Free | Premium (as listed) |
|---|---|---|
| Email masks | 5 | Unlimited |
| Replying through a mask | No | Yes, within 3 months of receipt |
| Tracker removal | Yes | Yes |
| Blocking promotional email | No | Yes |
| Mask domain | Shared mozmail.com addresses | Any word @yourlabel.mozmail.com |
| Price shown | Free | Not displayed |
| Sign-up | Open | Waitlist |
The premium email domain is a mozmail.com subdomain
Premium's headline feature beyond volume is what Mozilla calls a "unique Relay email domain", which lets you invent masks on the spot by putting any word before the @ symbol. Read the example on the page, though: restaurant@yourdomain.mozmail.com. It is a subdomain of mozmail.com, not a domain of yours. You choose the label; Mozilla owns the domain.
Nowhere on the pages we read does Relay offer to work with a domain you actually own, and that distinction matters more over time than it first appears. Addresses on a provider's domain live and die with the provider and your account. Addresses on a domain you own can be pointed at any service or mail server, for as long as you keep the registration. If you build years of sign-ups on yourlabel.mozmail.com, those addresses are only ever as portable as Mozilla lets them be, which today is not at all.
Downgrading is handled better than most
Credit where it is due: Relay's answer to what happens when you stop paying is one of the better ones in this market. Their FAQ is clear that after a downgrade, forwarding continues on your existing masks, including the ones made on your premium subdomain. The part that keeps your accounts reachable survives.
What you lose is the ability to reply and the ability to grow. The FAQ says replying to forwarded messages stops, you can no longer create masks on the subdomain, and if you hold more than five masks in total you cannot create new ones anywhere. Your existing setup keeps working as a receive-only version of itself. How services degrade after payment stops varies enormously across this market; we've compared the failure modes in what happens if you stop paying.
What the pages leave unsaid
A fair review should also name the questions Mozilla's pages simply do not answer. The price of premium is the obvious one: nothing we could find on relay.firefox.com states what the subscription costs, which makes the waitlist hard to evaluate. The waitlist itself is unexplained: the pages do not say whether it is a queue, a regional rollout or a pause on new subscriptions, and there is no stated timeline for coming off it.
Bringing your own domain is not addressed at all, not even as a no. And while the FAQ covers the downgrade path in reasonable detail, and even says a lapsed subscriber can resubscribe and regain access to those features, it does not say whether the old subdomain itself comes back unchanged. None of these are accusations; they are gaps, and anyone planning around Relay for the long term deserves to know they are gaps.
Who Relay honestly serves well
If you want a free, trustworthy masking layer for light use, Relay is an easy recommendation. Five masks with tracker removal, from an organisation with Mozilla's record, at no cost, with the limits documented honestly, is a good deal by any measure. Someone who wants one address for newsletters, one for shopping and one for risky sign-ups, and who never needs to write back through a mask, may never hit a wall.
The people Relay does not currently serve are the ones who outgrow that: anyone building a mask-per-site habit, anyone who needs to answer through their masks, and anyone who wants addresses on a domain they control. For them, the free tier's cap arrives fast, and the upgrade that would lift it cannot, as of today, be straightforwardly bought. Other services in this space make different trade-offs; we've looked at SimpleLogin and Apple's Hide My Email with the same approach as this post.