Security settings#


You should not run JupyterHub without SSL encryption on a public network.

Security is the most important aspect of configuring Jupyter. Three (3) configuration settings are the main aspects of security configuration:

  1. SSL encryption (to enable HTTPS)

  2. Cookie secret (a key for encrypting browser cookies)

  3. Proxy authentication token (used for the Hub and other services to authenticate to the Proxy)

The Hub hashes all secrets (e.g. auth tokens) before storing them in its database. A loss of control over read-access to the database should have minimal impact on your deployment. If your database has been compromised, it is still a good idea to revoke existing tokens.

Enabling SSL encryption#

Since JupyterHub includes authentication and allows arbitrary code execution, you should not run it without SSL (HTTPS).

Using an SSL certificate#

This will require you to obtain an official, trusted SSL certificate or create a self-signed certificate. Once you have obtained and installed a key and certificate, you need to specify their locations in the configuration file as follows:

c.JupyterHub.ssl_key = '/path/to/my.key'
c.JupyterHub.ssl_cert = '/path/to/my.cert'

Some cert files also contain the key, in which case only the cert is needed. It is important that these files be put in a secure location on your server, where they are not readable by regular users.

If you are using a chain certificate, see also chained certificate for SSL in the JupyterHub Troubleshooting FAQ.

Using letsencrypt#

It is also possible to use letsencrypt to obtain a free, trusted SSL certificate. If you run letsencrypt using the default options, the needed configuration is (replace mydomain.tld by your fully qualified domain name):

c.JupyterHub.ssl_key = '/etc/letsencrypt/live/{mydomain.tld}/privkey.pem'
c.JupyterHub.ssl_cert = '/etc/letsencrypt/live/{mydomain.tld}/fullchain.pem'

If the fully qualified domain name (FQDN) is, the following would be the needed configuration:

c.JupyterHub.ssl_key = '/etc/letsencrypt/live/'
c.JupyterHub.ssl_cert = '/etc/letsencrypt/live/'

If SSL termination happens outside of the Hub#

In certain cases, for example, if the hub is running behind a reverse proxy, and SSL termination is being provided by NGINX, it is reasonable to run the hub without SSL.

To achieve this, remove c.JupyterHub.ssl_key and c.JupyterHub.ssl_cert from your configuration (setting them to None or an empty string does not have the same effect, and will result in an error).

Proxy authentication token#

The Hub authenticates its requests to the Proxy using a secret token that the Hub and Proxy agree upon. Note that this applies to the default ConfigurableHTTPProxy implementation. Not all proxy implementations use an auth token.

The value of this token should be a random string (for example, generated by openssl rand -hex 32). You can store it in the configuration file or an environment variable.

Generating and storing token in the configuration file#

You can set the value in the configuration file,

c.ConfigurableHTTPProxy.api_token = 'abc123...' # any random string

Generating and storing as an environment variable#

You can pass this value of the proxy authentication token to the Hub and Proxy using the CONFIGPROXY_AUTH_TOKEN environment variable:

export CONFIGPROXY_AUTH_TOKEN=$(openssl rand -hex 32)

This environment variable needs to be visible to the Hub and Proxy.

Default if token is not set#

If you do not set the Proxy authentication token, the Hub will generate a random key itself. This means that any time you restart the Hub, you must also restart the Proxy. If the proxy is a subprocess of the Hub, this should happen automatically (this is the default configuration).

Cookies used by JupyterHub authentication#

The following cookies are used by the Hub for handling user authentication.

This section was created based on this post from Discourse.


This is the login token used when visiting Hub-served pages that are protected by authentication, such as the main home, the spawn form, etc. If this cookie is set, then the user is logged in.

Resetting the Hub cookie secret effectively revokes this cookie.

This cookie is restricted to the path /hub/.


This is the cookie used for authenticating with a single-user server. It is set by the single-user server, after OAuth with the Hub.

Effectively the same as jupyterhub-hub-login, but for the single-user server instead of the Hub. It contains an OAuth access token, which is checked with the Hub to authenticate the browser.

Each OAuth access token is associated with a session id (see jupyterhub-session-id section below).

To avoid hitting the Hub on every request, the authentication response is cached. The cache key is comprised of both the token and session id, to avoid a stale cache.

Resetting the Hub cookie secret effectively revokes this cookie.

This cookie is restricted to the path /user/<username>, to ensure that only the user’s server receives it.


This is a random string, meaningless in itself, and the only cookie shared by the Hub and single-user servers.

Its sole purpose is to coordinate the logout of the multiple OAuth cookies.

This cookie is set to / so all endpoints can receive it, clear it, etc.


A short-lived cookie, used solely to store and validate OAuth state. It is only set while OAuth between the single-user server and the Hub is processing.

If you use your browser development tools, you should see this cookie for a very brief moment before you are logged in, with an expiration date shorter than jupyterhub-hub-login or jupyterhub-user-<username>.

This cookie should not exist after you have successfully logged in.

This cookie is restricted to the path /user/<username>, so that only the user’s server receives it.