Firefox Send

  1. My Firefox Account
  2. Firefox Send Tab To Device Not Working
  3. Firefox Send Pwa
  4. Firefox Send Replacement

308 Permanent Redirect - Firefox Send. To subscribe to the mailing list send e-mail to [email protected] with 'subscribe' in the Subject. To unsubscribe send e-mail to [email protected] with 'unsubscribe' in the Subject. Firefox Send lets you share files with end-to-end encryption and a link that automatically expires. So you can keep what you share private and make sure your stuff doesn’t stay online forever.

Responsive design is the practice of designing a website so it looks and works properly on a range of different devices — particularly mobile phones and tablets as well as desktops and laptops.

The most obvious factor here is screen size, but there are other factors as well, including the pixel density of the display and whether it supports touch. Responsive Design Mode gives you a simple way to simulate these factors, to test how your website will look and behave on different devices.

Toggling Responsive Design Mode

There are three ways to toggle Responsive Design Mode:

  • From the Firefox menu: Select Responsive Design Mode from the Web Developer submenu in the Firefox Menu (or Tools menu if you display the menu bar or are on macOS).
  • From the Developer Tools toolbox: Press the Responsive Design Mode button in the Toolbox's toolbar:
  • From the keyboard: Press Ctrl + Shift + M (or Cmd + Opt + M on macOS).

Controlling Responsive Design Mode

With Responsive Design Mode enabled, the content area for web pages is set to the screen size for a mobile device. Initially, it's set to 320 x 480 pixels.

Firefox Send

Note: The device you select when in Responsive Design Mode and the orientation (portrait or landscape) is saved between sessions.

Information for the selected device is centered over the display. From left to right, the display includes:

My Firefox Account

  • Name of the selected device - A drop-down list that includes whatever devices you have selected from the Device Settings screen.
  • Screen size - You can edit the width and height values to change the device size by editing a number directly or using the Up and Down keys to increase or decrease the value by 1 pixels on each keypress or hold and Shift to change the value by 10.
    • The mouse wheel changes the size values by 1 pixel at a time
    • You can also change the device's screen size by grabbing the bottom-right corner of the viewport and dragging it to the size you want.
  • Orientation (portrait or landscape) - This setting persists between sessions
    • Screenshots are saved to Firefox's default download location.

    • If you checked 'Screenshot to clipboard' in the Developer Tools Settings page, then the screenshot will be copied to the system clipboard.

  • DPR (pixel ratio) - Beginning with Firefox 68, the DPR is no longer editable; create a custom device in order to change the DPR
  • Throttling - A drop-down list where you can select the connection throttling to apply, for example 2G, 3G, or LTE
  • Enable/Disable touch simulation - Toggles whether or not Responsive Design Mode simulates touch events. While touch event simulation is enabled, mouse events are translated into touch events; this includes (starting in Firefox 79) translating a mouse-drag event into a touch-drag event. (Note that when touch simulation is enabled, this toolbar icon is blue; when simulation is disabled, it is black.

On the right end of the screen, three buttons allow you to:

  • Camera button - take a screenshot
  • Settings button - Opens the RDM settings menu
  • Close button - closes RDM mode and returns to regular browsing

The Settings menu includes the following commands:

  • Left-align Viewport - when checked moves the RDM viewport to the left side of the browser window
  • Show user agent - when checked displays the user agent string
  • The final two options define when the page is reloaded:
    • Reload when touch simulation is toggled: when this option is enabled, the page is reloaded whenever you toggle touch support.
    • Reload when user agent is changed: when this option is enabled, the page is reloaded whenever the user agent is changed.

Reloading on these changes can be helpful because certain page behaviors would otherwise not be applied. For example, many pages check for touch support on load and only add event handlers if it is supported, or only enable certain features on certain browsers.

However, if you are not interested in examining such features (maybe you are just checking the overall layout at different sizes), these reloads can waste time and possibly result in the loss of productive work, so it is useful to be able to control these reloads.

Now when you change such settings for the first time, you are given a warning message that tells you these reloads are no longer automatic, and informed about how you can make them automatic. For example:

Developer Toolbox with RDM

You can show or hide the Developer Tools toolbox independently of toggling Responsive Design Mode itself:

While Responsive Design Mode is enabled, you can continue browsing as you normally would in the resized content area.

Device selection

Just above the viewport there is a label 'no device selected'; click this to see a list of device names. Select a device, and Responsive Design Mode sets the following properties to match the selected device:

  • Screen size
  • Device pixel ratio (the ratio of device physical pixels to device-independent pixels)
  • Touch event simulation

Additionally, Firefox sets the User-Agent HTTP request header to identify itself as the default browser on the selected device. For example, if you've selected an iPhone, then Firefox identifies itself as Safari. The navigator.userAgent property is set to the same value.

The devices listed in the drop-down are just a subset of the devices that can be selected. At the end of the drop-down, there is an item labeled Edit list. Select this to see a panel containing all the choices, which enables you to check the devices you want to see in the drop-down. The set of devices, and the values associated with each device, are taken from You can also define a custom device, as described below.

Creating custom devices

You can create and save custom devices in Responsive Design Mode by clicking the Add Custom Device button. Each device can have its own:

  • Name
  • Size
  • DevicePixelRatio
  • User Agent String
  • Touch Screen

Also, you can preview the properties of existing devices by hovering over the name in the device modal, where they display in a tooltip.

Network throttling

Firefox Send

If you do all your development and testing using a very fast network connection, users may experience problems with your site if they are using a slower connection. In Responsive Design Mode, you can instruct the browser to emulate, very approximately, the characteristics of various different types of networks.

The characteristics emulated are:

  • Download speed
  • Upload speed
  • Minimum latency

The table below lists the numbers associated with each network type, but please do not rely on this feature for exact performance measurements; it's intended to give an approximate idea of the user experience in different conditions.

SelectionDownload speedUpload speedMinimum latency (ms)
GPRS50 KB/s20 KB/s500
Regular 2G250 KB/s50 KB/s300
Good 2G450 KB/s150 KB/s150
Regular 3G750 KB/s250 KB/s100
Good 3G1.5 MB/s750 KB/s40
Regular 4G/LTE4 MB/s3 MB/s20
DSL2 MB/s1 MB/s5
Wi-Fi30 MB/s15 MB/s2

To select a network, click the list box that's initially labeled 'No throttling':

What do you do when you need to send a file to someone you don’t interact with a lot?

Many of us use email attachments for small files, because it’s quick and easy to share modest amounts of data that way.

Sure, the attachment will probably lie around in the recipient’s mailbox for days, or months, or even years, which might not be quite what you had in mind…

…but when you send someone else a file, you can’t control what they do with it anyway, or how long they keep it, or how widely visible it is on their corporate network after they save it.

But email is no good for large files such as audio data or videos, because most email servers quite reasonably have a low limit on message sizes to stop the system getting clogged up by attachments.

So the usual fallback for sending files that you can’t or don’t want to transmit via email is to use a file sharing service instead, which is rather like using webmail, only without the messaging part.

You upload the file to a file sharing site, optionally setting various options that describe which other users can see it, and for how long, and then send the recipient an email that contains a download link where they can fetch the file at their leisure.

That worrying feeling

If you routinely use file sharing services, however, we’re sure you’ve experienced that worrying feeling that comes whenever you browse through the list of files you’ve shared in the past, especially if you were sending a file to someone you don’t deal with often.

What on earth was that file you once sent, and who on earth are the four users on the access control list?

Can you delete the file that you shared two years ago, and did you ever make a permanent backup, and if so, where did the file end up anyway?

The annoyance – and the small but ever-present cybersecurity risk – in leaving a litter of old files behind in various third-party websites is one that affects many of us…

…which is why we are occasional but enthusiastic users of Firefox Send, a free service from Mozilla that aims to let you share large files easily, but without the worry of what gets left behind and forgotten about.

When you upload a file to send DOT firefox DOT com, it gets encrypted in your browser before any data is send into the cloud; the decryption key is encoded into the URL for downloading the file; and the link thus generated is (by default, at least) valid for one download or 24 hours, whichever comes first.

Firefox Send Tab To Device Not Working

If the recipient downloads the file using the link you send them, the data gets decrypted in their browser only after it has been downloaded, and then it vanishes from Mozilla’s servers forever.

If both you and the recipient forget about the uploaded file altogether, then it vanishes anyway and you don’t have to wonder if it’s still sitting around somewhere for someone else to download.

While the file is still on Mozilla’s servers, the pre-upload encryption means that even Mozilla can’t decrypt the file anyway, because only the encrypted data was uploaded and not the key.

Firefox Send Pwa

(In fact, given that the temporarily stored files are no more use than shredded cabbage to Mozilla – or to any network hackers, law enforcment agents, data protection regulators and so on – there is every incentive for Mozilla delete the files as promised, in order to recover disk space that would be completely wasted otherwise.)

What’s good for the goose

Unfortunately, as with so many simple, free and effective online services, what’s good for the goose is good for the gander, too.

In other words, crooks love Firefox Send just as much as we do, because it lets them generate short-term links based on trusted URLs for sharing arbitrary files without leaving any leftover data in the cloud.

Firefox Send Replacement

The problem is that in the case of the crooks, they’re typically using Firefox Send for what you might call “data infiltration” – a way of importing malware files or attack tools onto a network they’ve already broken into without drawing undue attention to themselves.

Firefox send secure

That sort of operational tactic goes by the name of living off the land – a slightly misplaced metaphor, to be sure, but one that is now widely used in the cybersecurity industry to mean “fitting right in with everyday behaviour on the network”.

By using Firefox Send, the crooks don’t need to set up a file sharing server of their own at a legitimate-looking URL, and they don’t have to worry about making sure their URLs expire automatically after use.

Links that work only once are a thorn in the side of security researchers, because even if you manage to acquire a full URL as an indicator of compromise, you can’t go back to the URL to investigate what malevolent baggage it might have served up when it was used.

The crooks also make themselves harder to track because their malicious content is effectively hiding in plain sight at an IP number operated by Mozilla.

What now?

Hats off to Mozilla and the Firefox team: following recent suggestions from cybersecurity researchers that some tweaks to the service might be a good idea, such as a [Report Abuse] button to make it quick and easy to get dodgy links blocked…

…the company has suspended its service temporarily to address the issues, rather than simply handing out vague promises to look at changes in the future:

Firefox Send is temporarily unavailable while we work on product improvements.

We appreciate your patience while we make the Firefox Send experience better.

The holding page doesn’t actually say that the outage relates to the problem of abuse by cybercriminals, but Mozilla has issued a statement to say:

Before relaunching, we will be adding an abuse reporting mechanism to augment the existing Feedback form, and we will require all users wishing to share content using Firefox Send to sign in with a Firefox Account.

Until now, you could use Firefox Send without creating a Firefox account, although that limited your links to at most 24 hours, but it looks as though the days of free-in-all-senses use of Firefox Send are over.

We’re not sure quite how much of a dent Mozilla will make in the abuse of the service by requiring even occasional users to stump up email addresses and create yet another cloud account, but the organisation seems determined to keep the service alive while addressing the community’s geniune concerns.

What do you think?

Does your organisation block sites like Firefox Send anyway?

If so, do you think these changes will make you rethink your policy, given that Send’s auto-encrypt-before-upload and auto-purge-after-download features gives you two less things to worry when sending files via the cloud?