ngrok Agent Configuration File

The ngrok supports an optional, YAML configuration file which provides you with the power to run multiple tunnels simultaneously as well as to tweak some of ngrok's more advanced settings.

Default Locations

The default location of the ngrok agent's configuration file varies based on your operating system. The easiest way to find the configuration file location is to run:

ngrok config check

which will validate and print the location of the configuration file.

For the main operating systems we support, their default file locations are:

Linux: "~/.config/ngrok/ngrok.yml"
MacOS (Darwin): "~/Library/Application Support/ngrok/ngrok.yml"
Windows: "%HOMEPATH%\AppData\Local\ngrok\ngrok.yml"

Global Options

The following is a list of options that can be configured at the root of your configuration file and specify the behavior of the agent.

Name	Description
api_key	Specifies the ngrok API key used to connect to the ngrok API. This is only needed when using the `ngrok api` command and should not be confused with the authtoken.
authtoken	Specifies the authentication token (authtoken) used to connect to the ngrok service.
connect_timeout	How long to wait when establishing an agent session connection to the ngrok service. The default is 10s.
console_ui	Enable/disable the console UI
console_ui_color	Set the background color of the console UI
dns_resolver_ips	Consult these DNS servers for tunnel session DNS resolution.
heartbeat_interval	How often the ngrok agent should heartbeat to the ngrok servers defined as a duration. Default is 10s.
heartbeat_tolerance	Reconnect the agent tunnel session if the server does not respond to a heartbeat within this tolerance defined as a duration. Default is 15s.
inspect_db_size	The size in bytes of the upper limit on memory to allocate to save requests over HTTP tunnels for inspection and replay.
log_level	Logging level of detail. In increasing order of verbosity, possible values are:
log_format	Format of written log records.
log	Write logs to this target destination.
metadata	Opaque, user-supplied string that will be returned as part of the ngrok API response to the list online sessions resource for all tunnels started by this agent.
proxy_url	URL of an HTTP or SOCKS5 proxy to use for establishing the tunnel connection.
region	Choose the region where the ngrok agent will connect to host its tunnels.
remote_management	Set this to `true` to allow the ngrok agent to be remotely managed (stop, restart, update). Defaults to `true`.
root_cas	The root certificate authorities used to validate the TLS connection to the ngrok server.
server_addr	This is the URL of the ngrok server to connect to. You should only set this if you are using a custom ingress URL.
tunnels	A map of names to tunnel definitions. See tunnel definitions for more details.
update_channel	The update channel determines the stability of released builds to update to. Use `stable` for all production deployments.
update_check	This tells the ngrok agent if it should check for updates. Defaults to `true`.
version	Specifies the version of the config file to use.
web_addr	Network address to bind on for serving the local web interface and api.
web_allow_hosts	Host headers to allow access for on the local web interface and api, can be a combination of IP's, CIDR ranges, and/or hostname suffixes.

`api_key`

This option specifies the API key used to access the ngrok API through the ngrok api command. This is only needed when using the ngrok API and not the local ngrok agent API (available at localhost:4040/api). You can generate an API Key in the ngrok Dashboard and install it using the ngrok config add-api-key command.

ngrok.yml specifying an API key

api_key: 24yRd5U3DestCQapJrrVHLOqiAC_7RviwRqpd3wc9dKLujQZN

`authtoken`

This option specifies the authentication token (sometimes called tunnel credential) used to authenticate this agent when it connects to the ngrok service. After you've created an ngrok account, your dashboard will display the authtoken assigned to your account.

Your authtoken will work on multiple machines if you are just developing. When you want to deploy many agents on many devices, you can generate a unique authtoken for each device in the ngrok Dashboard or via the ngrok api credentials command.

ngrok.yml specifying an authtoken

authtoken: 4nq9771bPxe8ctg7LKr_2ClH7Y15Zqe4bWLWF9p

`connect_timeout`

How long to wait when establishing an agent session connection to the ngrok service. This is specified as a duration, with the default being 10s.

`console_ui`

This option allows you to enable or disable the console UI that is displayed in your terminal window after starting ngrok.


`true`		Enable the console UI
`false`		Disable the console UI
`iftty`	default	Enable the UI only if standard out is a TTY (not a file or pipe)

`console_ui_color`

The command sets the background color when displaying the console UI in the terminal. To choose a color other than black, set the value to transparent and change the background of your terminal window.


`transparent`		Don't set a background color when displaying the console UI
`black`	default	Set the console UI's background to black

`dns_resolver_ips`

Consult these DNS servers for tunnel session DNS resolution. By default, the ngrok agent will use the local system DNS servers to resolve.

`heartbeat_interval`

How often the ngrok agent should heartbeat to the ngrok servers defined as a duration. The default is 10s.

`heartbeat_tolerance`

Reconnect the agent tunnel session if the server does not respond to a heartbeat within this tolerance defined as a duration. The default is 15s.

`inspect_db_size`

This is the upper limit in bytes on memory to allocate when saving requests over HTTP tunnels for inspection and reply. The default is 0, which means 50MB.


positive integers		size in bytes of the upper limit on memory to allocate to save requests over HTTP tunnels for inspection and replay.
`0`	default	use the default allocation limit, 50MB
`-1`		disable the inspection database; this has the effective behavior of disabling inspection for all tunnels

`log_level`

This is the logging level of detail. In increasing order of verbosity, possible values are: crit, warn, error, info, and debug.

`log_format`

This is the format of written log records.


`logfmt`		human and machine friendly key/value pairs
`json`		newline-separated JSON objects
`term`	default	custom colored human format if standard out is a TTY, otherwise same as `logfmt`

`log`

This is the destination where ngrok should write the logs.


`stdout`		write to standard out
`stderr`		write to standard error
`false`	default	disable logging
other values		write log records to file path on disk

log: /var/log/ngrok.log

`metadata`

This is a user-supplied custom string that will be returned as part of the ngrok API response to the list online sessions resource for all tunnels started by this agent. This is a useful mechanism to identify tunnels by your own device or customer identifier. Maximum 4096 characters.

metadata: bad8c1c0-8fce-11e4-b4a9-0800200c9a66

`proxy_url`

This is the URL of an HTTP or SOCKS5 proxy to use for establishing the tunnel connection. Many HTTP proxies have connection size and duration limits that will cause ngrok to fail. Like many other networking tools, ngrok will also respect the environment variable http_proxy if it is set.

`region`

This is the region where the ngrok agent will connect to. You can only choose one region per agent session. Choosing the region closest to you usually improves latency and performance. By default, the ngrok agent attempts to choose the best region for you.

Region Code	Region Name
`us`	United States
`eu`	Europe
`ap`	Asia/Pacific
`au`	Australia
`sa`	South America
`jp`	Japan
`in`	India

`remote_management`

Set this to true to allow the ngrok agent to be remotely managed (stop, restart, update) via the ngrok API or the ngrok Dashboard. Defaults to true.

`root_cas`

This is the root certificate authorities used to validate the TLS connection to the ngrok server.


`trusted`	default	use only the trusted certificate root for the ngrok.com tunnel service
`host`		use the root certificates trusted by the host's operating system. This is helpful for working with machine-in-the-middle (MITM) proxies doing deep packet inspection (DPI).
other values		path to a certificate PEM file on disk with certificate authorities to trust

`server_addr`

This is the URL of the ngrok server to connect to. You should set this if you are using a custom ingress URL.

`tunnels`

This is a map of names to tunnel definitions. See tunnel definitions for more details.

`update_channel`

The update channel determines the stability of released builds to update to. Use 'stable' for all production deployments.


`stable`	default	These are builds that are ready to be used in production.
`unstable`		update to new nightly builds when available which could be broken. This should not be used in production.
`beta`		update to new beta builds when available which could be broken. This should not be used in production.

`update_check`

This tells the ngrok agent if it should check for updates. Defaults to true.

`version`

Specifies the version of the config file to use.

`web_addr`

This is the network address to bind on for serving the local agent web interface and API.

Network address		Bind to this network address
`127.0.0.1:4040`	default	default network address
`false`		disable the web UI

`web_allow_hosts`

These are a list of specifiers for what Host headers will be allowed to make requests agains the local agent web interface and API. Any port is stripped off the Host header before matching is performed.

Allow string		Example Host headers that would match
	default	requests to localhost-bound web interface or API endpoints are checked to have a localhost-like Host (localhost, 127.0.0.1, ::1, etc.)
8.8.8.8		an IP matches Host header (8.8.8.8)
1:2:3:4:5:6:7:8		an IPv6 matches Host header (1:2:3:4:5:6:7:8)
10.0.0.0/8		a CIDR range matches a Host header that is an IP address in that range (10.0.0.1 or 10.1.2.3)
1:2:3:4:5:6:7:8/16		a CIDR range matches a Host header that is an IPv6 address in that range (1:2:3:4:5:6:7:0)
example.com		a hostname without preceding period will match Host header exactly (example.com)
.example.com		a hostname with a preceding period Host header suffix (sub.example.com or foo.example.com)

Allow an IP address and a Domain as Host headers

web_allow_hosts:
  - 8.8.8.8
  - example.com

Tunnel definitions

The most common use of the configuration file is to define tunnel configurations. Defining tunnel configurations is useful because you may then start pre-configured tunnels by name from your command line without remembering all of the right arguments every time. You may also use this method to start as many tunnels as you like from a single ngrok agent.

Tunnels are defined as mapping of name -> configuration under the tunnels property in your configuration file.

Define two tunnels named 'httpbin' and 'demo'

tunnels:
  httpbin:
    proto: http
    addr: 8000
    domain: alan-httpbin.ngrok.dev
  demo:
    proto: http
    addr: 9090
    domain: demo.inconshreveable.com
    inspect: false

Start the tunnel named 'httpbin'

ngrok start httpbin

Each tunnel you define is a map of configuration option names to values. The name of a configuration option is usually the same as its corresponding command line switch with hyphens (--host-header becomes host_header: in the configuration file and --scheme becomes schemes. Tunnels can define a specific proto or use labels to dynamically connect to one or more matching ngrok Edges. All tunnels must define a specific addr that tells the agent where to send the traffic. Other properties are available and many are protocol-specific.

Common Tunnel Configuration Properties


`addr`	required	forward traffic to this local port number or network address. This can be just a port (
`metadata`	Optional	arbitrary user-defined metadata that will appear in the ngrok service API when listing tunnel sessions

HTTP Tunnel Configuration Properties


`basic_auth`	Array of `username:password` Strings	This is a list of username:password combinations to use for basic authenticate. Passwords must be at least 8 characters long.
`circuit_breaker`	Float	Reject requests when 5XX responses exceed this ratio
`compression`	`true`, `false`	gzip compress HTTP responses from your web service
`host_header`	`rewrite`, `preserve`, custom	Rewrite the HTTP Host header to this value, or `preserve` to leave it unchanged. The `rewrite` option will rewrite the host header to match the hostname of the upstream service you are sending traffic to.
`domain`	Any valid domain or hostname that you have previously registered with ngrok.	The domain to request. If using a custom domain, this requires registering in the ngrok dashboard and setting a DNS CNAME value. When using wildcard domains you will need to surround the value with single quotes (domain: '*.example.com').
`inspect`	`true`, `false`	enable/disable the http request inspection in the web and agent API (default: true)
`ip_restriction.allow_cidrs`	Array of CIDRs	Rejects connections that do not match the given CIDRs
`ip_restriction.deny_cidrs`	Array of CIDRs	Rejects connections that match the given CIDRs and allows all other CIDRs.
`mutual_tls_cas`	Valid system path	The path to the TLS certificate authority to verify client certs in mutual TLS
`oauth.allow_domains`	Array of Strings	Allow only OAuth2 users with these email domains
`oauth.allow_emails`	Array of Strings	Allow only OAuth users with these emails
`oauth.oauth_scopes`	Array of Strings	Request these OAuth2 scopes when a user authenticates
`oauth.provider`	String	enforce authentication OAuth2 provider on the endpoint, e.g. 'google'. For a lit of available providers, see OAuth2 providers.
`proto`	`http`	The tunnel protocol name. This defines the type of tunnel you would like to start.
`proxy_proto`	String	The version of PROXY protocol to use with this tunnel, empty if not using. Example values are 1 or 2.
`request_header.add`	Array of `key:value` Strings	The headers to add to the request in the key:value format.
`request_header.remove`	Array of Strings	The header keys to remove from the request.
`response_header.add`	Array of Strings	The headers to add to the response in the key:value format.
`response_header.remove`	Array of Strings	The header keys to remove from the response.
`schemes`	`http`, `https`	bind to an HTTPS endpoint (
`subdomain`	Any valid combination of letters, numbers, hyphens or periods.	subdomain name to request. If unspecified, ngrok provides a unique subdomain based on your account type.
`verify_webhook.provider`	String	Verify webhooks are signed by this provider, e.g. 'slack'. For a full list of providers, see Webhook Verification Providers.
`verify_webhook.secret`	String	The secret used by provider to sign webhooks, if there is one
`websocket_tcp_converter`	`true`, `false`	Convert ingress websocket connections to TCP upstream

TCP Tunnel Configuration Properties


`ip_restriction.allow_cidrs`	Array of CIDRs	Rejects connections that do not match the given CIDRs
`ip_restriction.deny_cidrs`	Array of CIDRs	Rejects connections that match the given CIDRs and allows all other CIDRs.
`proto`	`tcp`	The tunnel protocol name. This defines the type of tunnel you would like to start.
`proxy_proto`	String	The version of PROXY protocol to use with this tunnel, empty if not using. Example values are 1 or 2.
`remote_addr`	A valid TCP address from ngrok	bind the remote TCP address and port. These addresses can be reserved in the ngrok dashboard to use across sessions. For example: `remote_addr: 2.tcp.ngrok.io:21746`

TLS Tunnel Configuration Properties


`mutual_tls_cas`	Valid system path	The path to the TLS certificate authority to verify client certs for mutual TLS. You will also need to specify `key` and `crt` to enable mutual TLS.
`crt`	Valid system path	PEM TLS certificate at this path to terminate TLS traffic before forwarding locally. Requires `--key` to also be specified.
`domain`	Any valid domain or hostname that you have previously registered with ngrok.	The domain to request. If using a custom domain, this requires registering in the ngrok Dashboard and setting a DNS CNAME value. When using wildcard domains you will need to surround the value with single quotes (domain: '*.example.com').
`ip_restriction.allow_cidrs`	Array of CIDRs	Rejects connections that do not match the given CIDRs
`ip_restriction.deny_cidrs`	Array of CIDRs	Rejects connections that match the given CIDRs and allows all other CIDRs.
`key`	Valid system path	PEM TLS private key at this path to terminate TLS traffic before forwarding locally. Requires `--crt` to also be specified.
`proto`	`tls`	The tunnel protocol name. This defines the type of tunnel you would like to start.
`proxy_proto`	String	The version of PROXY protocol to use with this tunnel, empty if not using. Example values are 1 or 2.
`subdomain`	Any valid combination of letters, numbers, hyphens or periods.	subdomain name to request. If unspecified, ngrok provides a unique subdomain based on your account type.
`terminate_at`	`edge` or `agent`	Terminate at the ngrok "edge" or "agent". defaults to no termination or "edge" if `--crt` or `--key` are present

Labeled Tunnel Configuration Properties


`crt`	Valid system path	The path to a TLS certificate when doing TLS termination at the agent.
`inspect`	`true`, `false`	enable/disable the http request inspection in the web and agent API (default: true)
`key`	Valid system path	The path to a TLS key when doing TLS termination at the agent.
`labels`	A list of labels (name=value) that can be used to identify a tunnel to an ngrok Edge (specifically a tunnel group backend).	The labels for this tunnel in the format name=value.

Define two labeled tunnels

tunnels:
  my-cool-website:
    labels:
      - env=prod
      - team=infra
    addr: 8000
    inspect: false
  ssh-tunnel:
    labels:
      - hostname=my-hostname
      - service=ssh
      - team=development
    addr: 22

How Config Files get Merged

The --config flag in the ngrok command allows you to specify one or more ngrok configuration files to merge when starting the ngrok agent. The rules for merging are as follows:

Values from later configs override those from earlier configs. For example, if config1.yml and config2.yml both set api_key, then calling ngrok http --config config1.yml,config2.yml 80 will use the api_key from config2.yml.
Lists are overwritten using the last value.
Maps, including the tunnels map, are merged by key and in the case of a duplicate key, the latter value is taken.

Full Example

Below is an example configuration file with all the options filled in.

authtoken: 4nq9771bPxe8ctg7LKr_2ClH7Y15Zqe4bWLWF9p
api_key: 24yRd5U3DestCQapJrrVHLOqiAC_7RviwRqpd3wc9dKLujQZN
connect_timeout: 30s
console_ui: true
console_ui_color: transparent
dns_resolver_ips:
  - 1.1.1.1
  - 8.8.8.8
heartbeat_interval: 1m
heartbeat_tolerance: 5s
inspect_db_size: 104857600 # 100mb
inspect_db_size: 50000000
log_level: info
log_format: json
log: /var/log/ngrok.log
metadata: '{"serial": "00012xa-33rUtz9", "comment": "For customer alan@example.com"}'
proxy_url: socks5://localhost:9150
region: us
remote_management: false
root_cas: trusted
update_channel: stable
update_check: false
version: 2
web_addr: localhost:4040
tunnels:
  website:
    addr: 8888
    basic_auth:
      - "bob:bobpassword"
    schemes:
      - https
    host_header: "myapp.ngrok.dev"
    inspect: false
    proto: http
    domain: myapp.ngrok.dev

  e2etls:
    addr: 9000
    proto: tls
    domain: myapp.example.com
    crt: example.crt
    key: example.key

  iprestriction:
    ip_restriction:
      allow_cidrs:
        - 1.1.1.1/32
    addr: 8000
    proto: tcp

  ssh-access:
    addr: 22
    proto: tcp
    remote_addr: 1.tcp.ngrok.io:12345

  my-cool-website:
    labels:
      - env=prod
      - team=infra
    addr: 8000
    oauth:
      provider: google
    inspect: false

ngrok Agent Configuration File

Default Locations​

Global Options​

api_key​

ngrok.yml specifying an API key​

authtoken​

ngrok.yml specifying an authtoken​

connect_timeout​

console_ui​

console_ui_color​

dns_resolver_ips​

heartbeat_interval​

heartbeat_tolerance​

inspect_db_size​

log_level​

log_format​

log​

metadata​

proxy_url​

region​

remote_management​

root_cas​

server_addr​

tunnels​

update_channel​

update_check​

version​

web_addr​

web_allow_hosts​

Allow an IP address and a Domain as Host headers​

Tunnel definitions​

Define two tunnels named 'httpbin' and 'demo'​

Start the tunnel named 'httpbin'​

Common Tunnel Configuration Properties​

HTTP Tunnel Configuration Properties​

TCP Tunnel Configuration Properties​

TLS Tunnel Configuration Properties​

Labeled Tunnel Configuration Properties​

Define two labeled tunnels​

How Config Files get Merged​

Full Example​