Firefox Custom Reponsive Design View sizes

FirefoxResponsiveDesignCustomSizes

about:config

add a new String entry with the name:
devtools.responsiveUI.presets

And the value of (customize as you need):


[{
    "name": "Small",
    "key": "320x480",
    "width": 320,
    "height": 480
}, {
    "name": "iPhone3",
    "key": "320x480",
    "width": 320,
    "height": 480
}, {
    "name": "VGA (NTSC)",
    "key": "640x480",
    "width": 640,
    "height": 480
}, {
    "name": "WVGA",
    "key": "800x480",
    "width": 800,
    "height": 480
}, {
    "name": "SVGA",
    "key": "800x600",
    "width": 800,
    "height": 600
}, {
    "name": "iPhone4 Retina",
    "key": "640x960",
    "width": 640,
    "height": 960
}, {
    "name": "iPhone5",
    "key": "640x1136",
    "width": 640,
    "height": 1136
}, {
    "name": "iPad2 & Mini",
    "key": "1024x768",
    "width": 1024,
    "height": 768
}, {
    "name": "XGA",
    "key": "1152x864",
    "width": 1152,
    "height": 864
}, {
    "name": "WXGA",
    "key": "1280x600",
    "width": 1280,
    "height": 600
}, {
    "name": "HD 720",
    "key": "1280x720",
    "width": 1280,
    "height": 720
}, {
    "name": "WXGA",
    "key": "1280x768",
    "width": 1280,
    "height": 768
}, {
    "name": "WXGA",
    "key": "1280x800",
    "width": 1280,
    "height": 800
}, {
    "name": "SXGA",
    "key": "1280x1024",
    "width": 1280,
    "height": 1024
}, {
    "name": "Microsoft Surface RT",
    "key": "320x240",
    "width": 768,
    "height": 1366
}, {
    "name": "UXGA",
    "key": "1600x1200",
    "width": 1600,
    "height": 1200
}, {
    "name": "WSXGA+",
    "key": "1680x1050",
    "width": 1680,
    "height": 1050
}, {
    "name": "HD 1080",
    "key": "1920x1080",
    "width": 1920,
    "height": 1080
}, {
    "name": "WUXGA",
    "key": "1920x1200",
    "width": 1920,
    "height": 1200
}, {
    "name": "Retina iPad",
    "key": "2048x1536",
    "width": 1536,
    "height": 2048
}, {
    "name": "WQHD",
    "key": "2560x1440",
    "width": 2560,
    "height": 1440
}, {
    "name": "WQXGA",
    "key": "2560x1600",
    "width": 2560,
    "height": 1600
}]