an SSO and OAuth / OIDC login solution for Nginx using the auth_request module
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Vouch Proxy

GitHub stars Build Status Go Report Card MIT license GitHub version

An SSO solution for Nginx using the auth_request module. Vouch Proxy can protect all of your websites at once.

Vouch Proxy supports many OAuth and OIDC login providers and can enforce authentication to...

Please do let us know when you have deployed Vouch Proxy with your preffered IdP or library so we can update the list.

If Vouch is running on the same host as the Nginx reverse proxy the response time from the /validate endpoint to Nginx should be less than 1ms.

Table of Contents

What Vouch Proxy Does

Vouch Proxy (VP) forces visitors to login and authenticate with an IdP (such as one of the services listed above) before allowing them access to a website.

Vouch Proxy protects websites

VP can also be used as a Single Sign On (SSO) solution to protect all web applications in the same domain.

Vouch Proxy is a Single Sign On solution

After a visitor logs in Vouch Proxy allows access to the protected websites for several hours. Every request is checked by VP to ensure that it is valid.

VP can send the visitor's email, name and other information which the IdP provides (including access tokens) to the web application as HTTP headers. VP can be used to replace application user management entirely.

Installation and Configuration

Vouch Proxy relies on the ability to share a cookie between the Vouch Proxy server and the application it's protecting. Typically this will be done by running Vouch on a subdomain such as with apps running at and The protected domain is and the Vouch Proxy cookie must be set in this domain by setting to include or sometimes by setting vouch.cookie.domain to

  • cp ./config/config.yml_example_$OAUTH_PROVIDER ./config/config.yml
  • create OAuth credentials for Vouch Proxy at google or github, etc
    • be sure to direct the callback URL to the Vouch Proxy /auth endpoint
  • configure Nginx...

The following Nginx config assumes..

  • Nginx, and are running on the same server
  • both domains are served as https and have valid certs (if not, change to listen 80 and set to false)
server {
    listen 443 ssl http2;
    root /var/www/html/;

    ssl_certificate /etc/letsencrypt/live/;
    ssl_certificate_key /etc/letsencrypt/live/;

    # send all requests to the `/validate` endpoint for authorization
    auth_request /validate;

    location = /validate {
      # forward the /validate request to Vouch Proxy
      # be sure to pass the original host header
      proxy_set_header Host $http_host;

      # Vouch Proxy only acts on the request headers
      proxy_pass_request_body off;
      proxy_set_header Content-Length "";

      # optionally add X-Vouch-User as returned by Vouch Proxy along with the request
      auth_request_set $auth_resp_x_vouch_user $upstream_http_x_vouch_user;

      # optionally add X-Vouch-IdP-Claims-* custom claims you are tracking
      #    auth_request_set $auth_resp_x_vouch_idp_claims_groups $upstream_http_x_vouch_idp_claims_groups;
      #    auth_request_set $auth_resp_x_vouch_idp_claims_given_name $upstream_http_x_vouch_idp_claims_given_name;
      # optinally add X-Vouch-IdP-AccessToken or X-Vouch-IdP-IdToken
      #    auth_request_set $auth_resp_x_vouch_idp_accesstoken $upstream_http_x_vouch_idp_accesstoken;
      #    auth_request_set $auth_resp_x_vouch_idp_idtoken $upstream_http_x_vouch_idp_idtoken;

      # these return values are used by the @error401 call
      auth_request_set $auth_resp_jwt $upstream_http_x_vouch_jwt;
      auth_request_set $auth_resp_err $upstream_http_x_vouch_err;
      auth_request_set $auth_resp_failcount $upstream_http_x_vouch_failcount;

      # Vouch Proxy can run behind the same Nginx reverse proxy
      # may need to comply to "upstream" server naming
      # proxy_pass;
      # proxy_set_header Host $http_host;

    # if validate returns `401 not authorized` then forward the request to the error401block
    error_page 401 = @error401;

    location @error401 {
        # redirect to Vouch Proxy for login
        return 302$scheme://$http_host$request_uri&vouch-failcount=$auth_resp_failcount&X-Vouch-Token=$auth_resp_jwt&error=$auth_resp_err;
        # you usually *want* to redirect to Vouch running behind the same Nginx config proteced by https
        # but to get started you can just forward the end user to the port that vouch is running on
        # return 302$scheme://$http_host$request_uri&vouch-failcount=$auth_resp_failcount&X-Vouch-Token=$auth_resp_jwt&error=$auth_resp_err;

    location / {
      # forward authorized requests to your service
      # you may need to set these variables in this block as per
      #    auth_request_set $auth_resp_x_vouch_user $upstream_http_x_vouch_user
      #    auth_request_set $auth_resp_x_vouch_idp_claims_groups $upstream_http_x_vouch_idp_claims_groups;
      #    auth_request_set $auth_resp_x_vouch_idp_claims_given_name $upstream_http_x_vouch_idp_claims_given_name;

      # set user header (usually an email)
      proxy_set_header X-Vouch-User $auth_resp_x_vouch_user;
      # optionally pass any custom claims you are tracking
      #     proxy_set_header X-Vouch-IdP-Claims-Groups $auth_resp_x_vouch_idp_claims_groups;
      #     proxy_set_header X-Vouch-IdP-Claims-Given_Name $auth_resp_x_vouch_idp_claims_given_name;
      # optionally pass the accesstoken or idtoken
      #     proxy_set_header X-Vouch-IdP-AccessToken $auth_resp_x_vouch_idp_accesstoken;
      #     proxy_set_header X-Vouch-IdP-IdToken $auth_resp_x_vouch_idp_idtoken;

If Vouch is configured behind the same nginx reverseproxy (perhaps so you can configure ssl) be sure to pass the Host header properly, otherwise the JWT cookie cannot be set into the domain

server {
    listen 443 ssl http2;
    ssl_certificate /etc/letsencrypt/live/;
    ssl_certificate_key /etc/letsencrypt/live/;

    location / {
      # be sure to pass the original host header
      proxy_set_header Host $http_host;

Vouch Proxy "in a path"

As of v0.33.0 Vouch Proxy can be served within an Nginx location (path) by configuring vouch.document_root: /vp_in_a_path

This avoids the need to setup a separate domain for Vouch Proxy such as For example VP login will be served from

server {
    listen 443 ssl http2;

    ssl_certificate /etc/letsencrypt/live/;
    ssl_certificate_key /etc/letsencrypt/live/;

    # This location serves all Vouch Proxy endpoints as /vp_in_a_path/$uri
    #   including /vp_in_a_path/validate, /vp_in_a_path/login, /vp_in_a_path/logout, /vp_in_a_path/auth, /vp_in_a_path/auth/$STATE, etc
    location /vp_in_a_path {
      proxy_pass; # must not! have a slash at the end
      proxy_set_header Host $http_host;
      proxy_pass_request_body off;
      proxy_set_header Content-Length "";

      # these return values are used by the @error401 call
      auth_request_set $auth_resp_jwt $upstream_http_x_vouch_jwt;
      auth_request_set $auth_resp_err $upstream_http_x_vouch_err;
      auth_request_set $auth_resp_failcount $upstream_http_x_vouch_failcount;

    # if /vp_in_a_path/validate returns `401 not authorized` then forward the request to the error401block
    error_page 401 = @error401;

    location @error401 {
        # redirect to Vouch Proxy for login
        return 302$scheme://$http_host$request_uri&vouch-failcount=$auth_resp_failcount&X-Vouch-Token=$auth_resp_jwt&error=$auth_resp_err;

    location / {
      auth_request /vp_in_a_path/validate;
      # see the Nginx config above for additional headers which can be set from Vouch Proxy

Additional Nginx Configurations

Additional Nginx configurations can be found in the examples directory.

Configuring via Environmental Variables

Here's a minimal setup using Google's OAuth... \
  OAUTH_CLIENT_SECRET=secretsecret \

Environmental variable names are documented in config/config.yml_example

All lists with multiple values must be comma separated: VOUCH_DOMAINS=","

The variable VOUCH_CONFIG can be used to set an alternate location for the configuration file. VOUCH_ROOT can be used to set an alternate root directory for Vouch Proxy to look for support files.

Tips, Tricks and Advanced Configurations

All Vouch Proxy configuration items are documented in config/config.yml_example

Please do help us to expand this list.

Scopes and Claims

With Vouch Proxy you can request various scopes (standard and custom) to obtain more information about the user or gain access to the provider's APIs. Internally, Vouch Proxy launches a requests to user_info_url after successful authentication. The required claims are extracted from the provider's response and stored in the VP cookie.

Additional claims and tokens will be added to the VP cookie and can make it large

The VP cookie may be split into several cookies to accomdate browser cookie size limits. But if you need it, you need it. Large cookies and headers require Nginx to be configured with larger buffers. See large_client_header_buffers and proxy_buffer_size for more information.

Setup scopes and claims in Vouch Proxy with Nginx

  1. Configure Vouch Proxy for Nginx and your IdP as normal (See: Installation and Configuration)

  2. Set the necessary scopes in the oauth section of the vouch-proxy config.yml (example config)

    1. set idtoken: X-Vouch-IdP-IdToken in the headers section of vouch-proxy's config.yml
    2. log in and call the /validate endpoint in a modern browser
    3. check the response header for a X-Vouch-IdP-IdToken header
    4. copy the value of the header into the debugger at and ensure that the necessary claims are part of the jwt
    5. if they are not, you need to adjust the scopes in the oauth section of your config.yml or reconfigure your oauth provider
  3. Set the necessary claims in the header section of the vouch-proxy config.yml

    1. log in and call the /validate endpoint in a modern browser
    2. check the response headers for headers of the form X-Vouch-IdP-Claims-<ClaimName>
    3. If they are not there clear your cookies and cached browser data
    4. 🐞 If they are still not there but exist in the jwt (esp. custom claims) there might be a bug
    5. remove the idtoken: X-Vouch-IdP-IdToken from the headers section of vouch-proxy's config.yml if you don't need it
  4. Use auth_request_set after auth_request inside the protected location in the nginx server.conf

  5. Consume the claim (example nginx config)

Running from Docker

docker run -d \
    -p 9090:9090 \
    --name vouch-proxy \
    -v ${PWD}/config:/config \


docker run -d \
    -p 9090:9090 \
    --name vouch-proxy \
    -e \
    -e OAUTH_PROVIDER=google \
    -e OAUTH_CLIENT_ID=1234 \
    -e OAUTH_CLIENT_SECRET=secretsecret \

As of v0.36.0 the docker process in the container runs as user vouch with UID 999 and GID 999. You may need to set the permissions of /config/config.yml and /config/secret to correspond to be readable by this user, or otherwise use docker run --user $UID:$GID ... or perhaps build the docker container from source and use the available ARGs for UID and GID.

Automated container builds for each Vouch Proxy release are available from Each release produces..

a minimal go binary container built from Dockerfile

  • such as

an alpine based container built from Dockerfile.alpine


Vouch Proxy arm images are available on Docker Hub

  • voucher/vouch-proxy:latest-arm

Kubernetes Nginx Ingress

If you are using kubernetes with nginx-ingress, you can configure your ingress with the following annotations (note quoting the auth-signin annotation): "$scheme://$http_host$request_uri&vouch-failcount=$auth_resp_failcount&X-Vouch-Token=$auth_resp_jwt&error=$auth_resp_err" X-Vouch-User |
      # these return values are used by the @error401 call
      auth_request_set $auth_resp_jwt $upstream_http_x_vouch_jwt;
      auth_request_set $auth_resp_err $upstream_http_x_vouch_err;
      auth_request_set $auth_resp_failcount $upstream_http_x_vouch_failcount;
      # when VP is hosted externally to k8s ensure the SSL cert is valid to avoid MITM risk
      # proxy_ssl_trusted_certificate /etc/ssl/certs/ca-certificates.crt;
      # proxy_ssl_session_reuse on;
      # proxy_ssl_verify_depth 2;
      # proxy_ssl_verify on;

Helm Charts are maintained by punkle, martina-if and halkeye and are available at

Compiling from source and running the binary

  ./ goget
  ./ build

As of v0.29.0 all templates, static assets and configuration defaults in .defaults.yml are built into the static binary using go:embed directives.

/login and /logout endpoint redirection

As of v0.11.0 additional checks are in place to reduce the attack surface of url redirection.


The passed URL...

  • must start with either http or https
  • must have a domain overlap with either a domain in the list or the vouch.cookie.domain (if either of those are configured)
  • cannot have a parameter which includes a URL to prevent URL chaining attacks


The Vouch Proxy /logout endpoint accepts a url parameter in the query string which can be used to 302 redirect a user to your orignal OAuth provider/IDP/OIDC provider's revocation_endpoint

this url must be present in the configuration file on the list vouch.post_logout_redirect_uris

# in order to prevent redirection attacks all redirected URLs to /logout must be specified
# the URL must still be passed to Vouch Proxy as${ONE OF THE URLS BELOW}
  # your apps login page
  # your IdPs logout enpoint
  # from
  # you may be daisy chaining to your IdP

Note that your IdP will likely carry their own, separate post_logout_redirect_uri list.

logout resources..

Troubleshooting, Support and Feature Requests (Read this before submitting an issue at GitHub)

Getting the stars to align between Nginx, Vouch Proxy and your IdP can be tricky. We want to help you get up and running as quickly as possible. The most common problem is..

I'm getting an infinite redirect loop which returns me to my IdP (Google/Okta/GitHub/...)

Double check that you are running Vouch Proxy and your apps on a common domain that can share cookies. For example, and can share cookies on the domain. (It will not work if you are trying to use and

You may need to explicitly define the domain that the cookie should be set on. You can do this in the config file by setting the option:

    # force the domain of the cookie to set

If you continue to have trouble, try the following:

  • turn on vouch.testing: true. This will slow down the loop.

  • set vouch.logLevel: debug.

  • the Host: header in the http request, the oauth.callback_url and the configured must all align so that the cookie that carries the JWT can be placed properly into the browser and then returned on each request

  • it helps to think like a cookie.

    • a cookie is set into a domain. If you have and protected by Vouch Proxy, you want the Vouch Proxy cookie to be set into
    • if you authenticate to the cookie will not be able to be seen by
    • unless you are using https, you should set false
    • cookies are available to all ports of a domain
  • please see the issues which have been closed that mention redirect

Okay, I looked at the issues and have tried some things with my configs but it's still not working

Please submit a new issue in the following fashion..


  • set vouch.testing: true
  • set vouch.logLevel: debug
  • conduct two full round trips of ./vouch-proxy capturing the output..
    • VP startup
    • /validate
    • /login - even if the error is here
    • /auth
    • /validate - capture everything
  • put all your logs and config in a gist.
  • ./ bug_report is your friend

But read this anyways because we'll ask you to read it if you don't follow these instruction. :)

  • turn on vouch.testing: true and set vouch.logLevel: debug.
  • use a gist or another paste service such as DO NOT PUT YOUR LOGS AND CONFIG INTO THE GITHUB ISSUE. Using a paste service is important as it will maintain spacing and will provide line numbers and formatting. We are hunting for needles in haystacks with setups with several moving parts, these features help considerably. Paste services save your time and our time and help us to help you quickly. You're more likely to get good support from us in a timely manner by following this advice.
  • run ./ bug_report secretpass [anothersecret..] which will create a redacted version of your config and logs removing each of those strings
    • and follow the instructions at the end to redact your Nginx config
  • all of those go into a gist
  • then open a new issue in this repository
  • or visit our IRC channel #vouch on

A bug report can be generated from a docker environment using the image...

docker run --name vouch_proxy -v $PWD/config:/config -v $PWD/certs:/certs -it --rm --entrypoint / bug_report someothersecret


We'd love to have you contribute! Please refer to our contribution guidelines for details.

Advanced Authorization Using OpenResty

OpenResty® is a full-fledged web platform that integrates the standard Nginx core, LuaJIT, many carefully written Lua libraries, lots of high quality 3rd-party Nginx modules, and most of their external dependencies.

You can replace nginx with OpenResty fairly easily.

With OpenResty and Lua it is possible to provide customized and advanced authorization on any header or claims vouch passes down.

OpenResty and configs for a variety of scenarios are available in the examples directory.

The flow of login and authentication using Google Oauth

  • Bob visits

  • the Nginx reverse proxy...

    • recieves the request for from Bob
    • uses the auth_request module configured for the /validate path
    • /validate is configured to proxy_pass requests to the authentication service at
      • if /validate returns...
        • 200 OK then SUCCESS allow Bob through
        • 401 NotAuthorized then
          • respond to Bob with a 302 redirect to
  • Vouch Proxy

    • recieves the request for from Bob via Nginx proxy_pass
    • looks for a cookie named "oursitesSSO" that contains a JWT
    • if the cookie is found, and the JWT is valid
      • returns 200 OK to Nginx, which will allow access (bob notices nothing)
    • if the cookie is NOT found, or the JWT is NOT valid
      • return 401 NotAuthorized to Nginx (which forwards the request on to login)
  • Bob is first forwarded briefly to

    • clears out the cookie named "oursitesSSO" if it exists
    • generates a nonce and stores it in session variable $STATE
    • stores the url from the query string in session variable $requestedURL
    • respond to Bob with a 302 redirect to Google's OAuth Login form, including the $STATE nonce
  • Bob logs into his Google account using Oauth

    • after successful login
    • Google responds to Bob with a 302 redirect to$STATE
  • Bob is forwarded to$STATE

    • if the $STATE nonce from the url matches the session variable "state"
    • make a "third leg" request of Google (server to server) to exchange the OAuth code for Bob's user info including email address
    • if the email address matches the domain (it does)
      • issue bob a JWT in the form of a cookie named "oursitesSSO"
      • retrieve the session variable $requestedURL and 302 redirect bob back to

Note that outside of some innocuos redirection, Bob only ever sees and the Google Login screen in his browser. While Vouch does interact with Bob's browser several times, it is just to set cookies, and if the 302 redirects work properly Bob will log in quickly.

Once the JWT is set, Bob will be authorized for all other sites which are configured to use from the auth_request Nginx module.

The next time Bob is forwarded to google for login, since he has already authorized the Vouch Proxy OAuth app, Google immediately forwards him back and sets the cookie and sends him on his merry way. In some browsers such as Chrome, Bob may not even notice that he logged in using Vouch Proxy.