# Supported Chrome Command Line Switches

> Command line switches supported by Electron.

You can use [app.commandLine.appendSwitch][append-switch] to append them in
your app's main script before the [ready][ready] event of the [app][app] module
is emitted:

```javascript
const {app} = require('electron');
app.commandLine.appendSwitch('remote-debugging-port', '8315');
app.commandLine.appendSwitch('host-rules', 'MAP * 127.0.0.1');

app.on('ready', () => {
  // Your code here
});
```

## --ignore-connections-limit=`domains`

Ignore the connections limit for `domains` list separated by `,`.

## --disable-http-cache

Disables the disk cache for HTTP requests.

## --disable-http2

Disable HTTP/2 and SPDY/3.1 protocols.

## --remote-debugging-port=`port`

Enables remote debugging over HTTP on the specified `port`.

## --js-flags=`flags`

Specifies the flags passed to JS engine. It has to be passed when starting
Electron if you want to enable the `flags` in the main process.

```bash
$ electron --js-flags="--harmony_proxies --harmony_collections" your-app
```

## --proxy-server=`address:port`

Use a specified proxy server, which overrides the system setting. This switch
only affects requests with HTTP protocol, including HTTPS and WebSocket
requests. It is also noteworthy that not all proxy servers support HTTPS and
WebSocket requests.

## --proxy-bypass-list=`hosts`

Instructs Electron to bypass the proxy server for the given semi-colon-separated
list of hosts. This flag has an effect only if used in tandem with
`--proxy-server`.

For example:

```javascript
app.commandLine.appendSwitch('proxy-bypass-list', '<local>;*.google.com;*foo.com;1.2.3.4:5678')
```

Will use the proxy server for all hosts except for local addresses (`localhost`,
`127.0.0.1` etc.), `google.com` subdomains, hosts that contain the suffix
`foo.com` and anything at `1.2.3.4:5678`.

## --proxy-pac-url=`url`

Uses the PAC script at the specified `url`.

## --no-proxy-server

Don't use a proxy server and always make direct connections. Overrides any other
proxy server flags that are passed.

## --host-rules=`rules`

A comma-separated list of `rules` that control how hostnames are mapped.

For example:

* `MAP * 127.0.0.1` Forces all hostnames to be mapped to 127.0.0.1
* `MAP *.google.com proxy` Forces all google.com subdomains to be resolved to
  "proxy".
* `MAP test.com [::1]:77` Forces "test.com" to resolve to IPv6 loopback. Will
  also force the port of the resulting socket address to be 77.
* `MAP * baz, EXCLUDE www.google.com` Remaps everything to "baz", except for
  "www.google.com".

These mappings apply to the endpoint host in a net request (the TCP connect
and host resolver in a direct connection, and the `CONNECT` in an HTTP proxy
connection, and the endpoint host in a `SOCKS` proxy connection).

## --host-resolver-rules=`rules`

Like `--host-rules` but these `rules` only apply to the host resolver.

## --auth-server-whitelist=`url`

A comma-separated list of servers for which integrated authentication is enabled.

For example:

```
--auth-server-whitelist='*example.com, *foobar.com, *baz'
```

then any `url` ending with `example.com`, `foobar.com`, `baz` will be considered
for integrated authentication. Without `*` prefix the url has to match exactly.

## --auth-negotiate-delegate-whitelist=`url`

A comma-separated list of servers for which delegation of user credentials is required.
Without `*` prefix the url has to match exactly.

## --ignore-certificate-errors

Ignores certificate related errors.

## --ppapi-flash-path=`path`

Sets the `path` of the pepper flash plugin.

## --ppapi-flash-version=`version`

Sets the `version` of the pepper flash plugin.

## --log-net-log=`path`

Enables net log events to be saved and writes them to `path`.

## --ssl-version-fallback-min=`version`

Sets the minimum SSL/TLS version (`tls1`, `tls1.1` or `tls1.2`) that TLS
fallback will accept.

## --cipher-suite-blacklist=`cipher_suites`

Specifies comma-separated list of SSL cipher suites to disable.

## --disable-renderer-backgrounding

Prevents Chromium from lowering the priority of invisible pages' renderer
processes.

This flag is global to all renderer processes, if you only want to disable
throttling in one window, you can take the hack of
[playing silent audio][play-silent-audio].

## --enable-logging

Prints Chromium's logging into console.

This switch can not be used in `app.commandLine.appendSwitch` since it is parsed
earlier than user's app is loaded, but you can set the `ELECTRON_ENABLE_LOGGING`
environment variable to achieve the same effect.

## --v=`log_level`

Gives the default maximal active V-logging level; 0 is the default. Normally
positive values are used for V-logging levels.

This switch only works when `--enable-logging` is also passed.

## --vmodule=`pattern`

Gives the per-module maximal V-logging levels to override the value given by
`--v`. E.g. `my_module=2,foo*=3` would change the logging level for all code in
source files `my_module.*` and `foo*.*`.

Any pattern containing a forward or backward slash will be tested against the
whole pathname and not just the module. E.g. `*/foo/bar/*=2` would change the
logging level for all code in the source files under a `foo/bar` directory.

This switch only works when `--enable-logging` is also passed.

## --disable-gpu

Disables the use of the GPU in the renderer process. If this is set with the
`--disable-gpu-compositing` switch, *offscreen rendering* will use a software
output device, which has much better overall performance but lacks of WebGL
and 3D CSS support.

## --disable-gpu-compositing

Disables the use of the GPU compositing in the renderer process. This should be
set with the `--disable-gpu` switch for *offscreen rendering*.

``` javascript
const {app, BrowserWindow} = require('electron');

app.commandLine.appendSwitch('disable-gpu');
app.commandLine.appendSwitch('disable-gpu-compositing');

let win = new BrowserWindow({
  webPreferences: {
    offscreen: true
  }
});
win.loadURL('http://github.com');

win.webContents.on('paint', (event, dirty, data) => {
  updateBitmap(dirty, data);
});
```

[app]: app.md
[append-switch]: app.md#appcommandlineappendswitchswitch-value
[ready]: app.md#event-ready
[play-silent-audio]: https://github.com/atom/atom/pull/9485/files