diff --git a/docs/installer.py b/docs/installer.py
index 3aea3ae70..360233c05 100644
--- a/docs/installer.py
+++ b/docs/installer.py
@@ -78,7 +78,9 @@ def get_nightly_url():
     if is_macos:
         return base + '.dmg'
     arch = 'x86_64' if is64bit else 'i686'
-    return base + '-' + arch + '.txz'
+    url = base + '-' + arch + '.txz'
+    i = urllib.urlopen(url)
+    return url, int(i.getheader('content-length'))
 
 
 def get_latest_release_data():
@@ -203,7 +205,8 @@ def main(dest=None, launch=True, installer=None):
         installer = download_installer(url, size)
     else:
         if installer == 'nightly':
-            url = get_nightly_url()
+            url, size = get_nightly_url()
+            installer = download_installer(url, size)
         else:
             installer = os.path.abspath(installer)
             if not os.access(installer, os.R_OK):
diff --git a/docs/installer.sh b/docs/installer.sh
index 850fa0419..a29b78c4f 100644
--- a/docs/installer.sh
+++ b/docs/installer.sh
@@ -25,6 +25,270 @@ echo Using python executable: $python
 $python -c "import sys; script_launch=lambda:sys.exit('Download of installer failed!'); exec(sys.stdin.read()); script_launch()" "$@" <<'INSTALLER_HEREDOC'
 # {{{
 # HEREDOC_START
+#!/usr/bin/env python3
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
+
+from __future__ import (
+    absolute_import, division, print_function, unicode_literals
+)
+
+import atexit
+import json
+import os
+import platform
+import re
+import shlex
+import shutil
+import subprocess
+import sys
+import tempfile
+
+py3 = sys.version_info[0] > 2
+is64bit = platform.architecture()[0] == '64bit'
+is_macos = 'darwin' in sys.platform.lower()
+if is_macos:
+    mac_ver = tuple(map(int, platform.mac_ver()[0].split('.')))
+    if mac_ver[:2] < (10, 12):
+        raise SystemExit('Your version of macOS is too old, at least 10.12 is required')
+
+try:
+    __file__
+    from_file = True
+except NameError:
+    from_file = False
+
+if py3:
+    unicode = str
+    raw_input = input
+    import urllib.request as urllib
+
+    def encode_for_subprocess(x):
+        return x
+else:
+    from future_builtins import map
+    import urllib2 as urllib
+
+    def encode_for_subprocess(x):
+        if isinstance(x, unicode):
+            x = x.encode('utf-8')
+        return x
+
+
+def run(*args):
+    if len(args) == 1:
+        args = shlex.split(args[0])
+    args = list(map(encode_for_subprocess, args))
+    ret = subprocess.Popen(args).wait()
+    if ret != 0:
+        raise SystemExit(ret)
+
+
+class Reporter:  # {{{
+
+    def __init__(self, fname):
+        self.fname = fname
+        self.last_percent = 0
+
+    def __call__(self, blocks, block_size, total_size):
+        percent = (blocks*block_size)/float(total_size)
+        report = '\rDownloaded {:.1%}         '.format(percent)
+        if percent - self.last_percent > 0.05:
+            self.last_percent = percent
+            print(report, end='')
+            sys.stdout.flush()
+# }}}
+
+
+def get_nightly_url():
+    base = 'https://github.com/kovidgoyal/kitty/releases/download/nightly/kitty-nightly'
+    if is_macos:
+        return base + '.dmg'
+    arch = 'x86_64' if is64bit else 'i686'
+    url = base + '-' + arch + '.txz'
+    i = urllib.urlopen(url)
+    return url, int(i.getheader('content-length'))
+
+
+def get_latest_release_data():
+    print('Checking for latest release on GitHub...')
+    req = urllib.Request('https://api.github.com/repos/kovidgoyal/kitty/releases/latest', headers={'Accept': 'application/vnd.github.v3+json'})
+    try:
+        res = urllib.urlopen(req).read().decode('utf-8')
+    except Exception as err:
+        raise SystemExit('Failed to contact {} with error: {}'.format(req.get_full_url(), err))
+    data = json.loads(res)
+    html_url = data['html_url'].replace('/tag/', '/download/').rstrip('/')
+    for asset in data.get('assets', ()):
+        name = asset['name']
+        if is_macos:
+            if name.endswith('.dmg'):
+                return html_url + '/' + name, asset['size']
+        else:
+            if name.endswith('.txz'):
+                if is64bit:
+                    if name.endswith('-x86_64.txz'):
+                        return html_url + '/' + name, asset['size']
+                else:
+                    if name.endswith('-i686.txz'):
+                        return html_url + '/' + name, asset['size']
+    raise SystemExit('Failed to find the installer package on github')
+
+
+def do_download(url, size, dest):
+    print('Will download and install', os.path.basename(dest))
+    reporter = Reporter(os.path.basename(dest))
+
+    # Get content length and check if range is supported
+    rq = urllib.urlopen(url)
+    headers = rq.info()
+    sent_size = int(headers['content-length'])
+    if sent_size != size:
+        raise SystemExit('Failed to download from {} Content-Length ({}) != {}'.format(url, sent_size, size))
+    with open(dest, 'wb') as f:
+        while f.tell() < size:
+            raw = rq.read(8192)
+            if not raw:
+                break
+            f.write(raw)
+            reporter(f.tell(), 1, size)
+    rq.close()
+    if os.path.getsize(dest) < size:
+        raise SystemExit('Download failed, try again later')
+    print('\rDownloaded {} bytes'.format(os.path.getsize(dest)))
+
+
+def clean_cache(cache, fname):
+    for x in os.listdir(cache):
+        if fname not in x:
+            os.remove(os.path.join(cache, x))
+
+
+def download_installer(url, size):
+    fname = url.rpartition('/')[-1]
+    tdir = tempfile.gettempdir()
+    cache = os.path.join(tdir, 'kitty-installer-cache')
+    if not os.path.exists(cache):
+        os.makedirs(cache)
+    clean_cache(cache, fname)
+    dest = os.path.join(cache, fname)
+    if os.path.exists(dest) and os.path.getsize(dest) == size:
+        print('Using previously downloaded', fname)
+        return dest
+    if os.path.exists(dest):
+        os.remove(dest)
+    do_download(url, size, dest)
+    return dest
+
+
+def macos_install(dmg, dest='/Applications', launch=True):
+    mp = tempfile.mkdtemp()
+    atexit.register(shutil.rmtree, mp)
+    run('hdiutil', 'attach', dmg, '-mountpoint', mp)
+    try:
+        os.chdir(mp)
+        app = 'kitty.app'
+        d = os.path.join(dest, app)
+        if os.path.exists(d):
+            shutil.rmtree(d)
+        dest = os.path.join(dest, app)
+        run('ditto', '-v', app, dest)
+        print('Successfully installed kitty into', dest)
+        if launch:
+            run('open', dest)
+    finally:
+        os.chdir('/')
+        run('hdiutil', 'detach', mp)
+
+
+def linux_install(installer, dest=os.path.expanduser('~/.local'), launch=True):
+    dest = os.path.join(dest, 'kitty.app')
+    if os.path.exists(dest):
+        shutil.rmtree(dest)
+    os.makedirs(dest)
+    print('Extracting tarball...')
+    run('tar', '-C', dest, '-xJof', installer)
+    print('kitty successfully installed to', dest)
+    kitty = os.path.join(dest, 'bin', 'kitty')
+    print('Use', kitty, 'to run kitty')
+    if launch:
+        run(kitty, '--detach')
+
+
+def main(dest=None, launch=True, installer=None):
+    if not dest:
+        if is_macos:
+            dest = '/Applications'
+        else:
+            dest = os.path.expanduser('~/.local')
+    machine = os.uname()[4]
+    if machine and machine.lower().startswith('arm'):
+        raise SystemExit(
+            'You are running on an ARM system. The kitty binaries are only'
+            ' available for x86 systems. You will have to build from'
+            ' source.')
+    if not installer:
+        url, size = get_latest_release_data()
+        installer = download_installer(url, size)
+    else:
+        if installer == 'nightly':
+            url, size = get_nightly_url()
+            installer = download_installer(url, size)
+        else:
+            installer = os.path.abspath(installer)
+            if not os.access(installer, os.R_OK):
+                raise SystemExit('Could not read from: {}'.format(installer))
+    if is_macos:
+        macos_install(installer, dest=dest, launch=launch)
+    else:
+        linux_install(installer, dest=dest, launch=launch)
+
+
+def script_launch():
+    # To test: python3 -c "import runpy; runpy.run_path('installer.py', run_name='script_launch')"
+    def path(x):
+        return os.path.expandvars(os.path.expanduser(x))
+
+    def to_bool(x):
+        return x.lower() in {'y', 'yes', '1', 'true'}
+
+    type_map = {x: path for x in 'dest installer'.split()}
+    type_map['launch'] = to_bool
+    kwargs = {}
+
+    for arg in sys.argv[1:]:
+        if arg:
+            m = re.match('([a-z_]+)=(.+)', arg)
+            if m is None:
+                raise SystemExit('Unrecognized command line argument: ' + arg)
+            k = m.group(1)
+            if k not in type_map:
+                raise SystemExit('Unrecognized command line argument: ' + arg)
+            kwargs[k] = type_map[k](m.group(2))
+    main(**kwargs)
+
+
+def update_intaller_wrapper():
+    # To run: python3 -c "import runpy; runpy.run_path('installer.py', run_name='update_wrapper')" installer.sh
+    with open(__file__, 'rb') as f:
+        src = f.read().decode('utf-8')
+    wrapper = sys.argv[-1]
+    with open(wrapper, 'r+b') as f:
+        raw = f.read().decode('utf-8')
+        nraw = re.sub(r'^# HEREDOC_START.+^# HEREDOC_END', lambda m: '# HEREDOC_START\n{}\n# HEREDOC_END'.format(src), raw, flags=re.MULTILINE | re.DOTALL)
+        if 'update_intaller_wrapper()' not in nraw:
+            raise SystemExit('regex substitute of HEREDOC failed')
+        f.seek(0), f.truncate()
+        f.write(nraw.encode('utf-8'))
+
+
+if __name__ == '__main__' and from_file:
+    main()
+elif __name__ == 'update_wrapper':
+    update_intaller_wrapper()
+elif __name__ == 'script_launch':
+    script_launch()
+
 # HEREDOC_END
 # }}}
 INSTALLER_HEREDOC