Last updated: 2026-07-09
Firefox Send was Mozilla's take on private file sharing: drop in a file, get an encrypted link, set it to expire or self-destruct after one download. People loved it and still look for it years later. It is not coming back — Mozilla discontinued the service in 2020 — but the need it filled is still real.
Relayium's async (stored-link) mode picks up that same idea: encrypt in the browser, share a link, watch it expire or burn. This article is an honest comparison — what Firefox Send did, how closely Relayium matches it, and where Relayium goes further with realtime peer-to-peer transfer, a CLI, and self-hosting.
Firefox Send launched from Mozilla in 2019 as a simple, privacy-minded way to share files: upload a file, the browser encrypted it, and you got a link you could send anywhere. The recipient needed no account to download. You could set the link to expire after a number of downloads or after a set time, and Mozilla marketed it as end-to-end encrypted.
Mozilla shut Firefox Send down in September 2020, citing abuse of the service for malware distribution and a decision to focus engineering elsewhere. There has been no successor from Mozilla and no announced plans to revive it — if you are hoping it comes back under its old name, it will not. That has left a real gap: a lot of people still want a free, private, link-based way to send a file that expires and that the host provider cannot read.
Relayium's async mode is built around the same shape of experience. You pick your files, your browser generates a random AES-256-GCM key locally, encrypts the files with it, and uploads the ciphertext. The server never sees the key and cannot decrypt what it stores — it is genuinely zero-knowledge, not just "encrypted at rest."
The decryption key travels only inside the link itself, in the URL fragment after the #, which browsers never transmit to any server. Whoever receives the link needs no account to download — they just open it, and their browser fetches the ciphertext and decrypts it locally with the key from the fragment. That is the core Firefox Send promise, intact: a link that carries its own key and that the server hosting it cannot read.
Like Firefox Send, every Relayium link has a lifespan you choose: 1 hour, 1 day, 3 days, or 7 days, or you can set it to burn after the very first complete download so it is gone the moment your recipient has the file. Once a link expires or burns, the stored ciphertext is deleted and the link stops working.
To be precise about what's stored where: this is a stored-link mode, so the encrypted file bytes genuinely do sit on Relayium's server between upload and download — it is zero-knowledge ciphertext the server cannot decrypt, but it is not a "the file never touches a server" setup. Creating a link does require the sender to sign in (it's tied to your account's storage quota); the recipient never needs an account to open or download it.
Firefox Send only ever did one thing — encrypted, async link sharing — and Relayium's stored mode covers that ground. But Relayium also has a mode Firefox Send never offered: realtime peer-to-peer transfer, where files stream directly between two open browsers over an end-to-end encrypted WebRTC channel and nothing is stored on a server at all. On the same network it needs no account for either side; sending across networks with a pairing code needs the sender to sign in, and the receiver still never does.
For people who want more control, Relayium also ships a free, open-source CLI (push/pull over SSH, cross-network send/receive, folder sync) and a self-hostable server you can run yourself — none of which Firefox Send ever had. The whole project is MIT-licensed and open source on GitHub.
No. Mozilla discontinued Firefox Send in September 2020 and has not revived it or announced a successor. Relayium's stored-link mode is a separate, independently built project designed to fill the same gap.
Yes, and the design is stronger in one respect: your browser generates a random AES-256-GCM key locally, and the key lives only in the link's URL fragment, which is never sent to the server. The server stores only ciphertext it cannot decrypt — a true zero-knowledge setup.
Yes. Choose 1 hour, 1 day, 3 days, or 7 days, or set the link to burn after the first complete download. After that, the stored ciphertext is deleted and the link no longer works.
Yes. Relayium is free and open source under the MIT license. Creating a stored download link requires the sender to sign in (links count against your account's storage quota), but the recipient never needs an account to download.
Send a private, expiring link the way Firefox Send used to — encrypted in your browser, unreadable by the server.
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