RESTful Web Interface

The VOLTTRON User Interface API (VUI) is provided by the VOLTTRON Web Service, and is intended to provide capabilities for building fully featured frontend applications. The VUI is a RESTful HTTP API for communicating with components of the VOLTTRON system.


The VUI is a built-in part of the VOLTTRON Web Service. To enable to VOLTTRON Web Service, bootstrap VOLTTRON within the virtual environment using the –web option:

python --web

Additionally, to enable the web service, it is necessary to add a bind-web-address key to the $VOLTTRON_HOME/config file. The value of this key represents address bound to by the platform web service for handling HTTP(s) requests. Typical addresses would be https://<hostname_or_ip>:8443 or http://<hostname_or_ip>:8080.


If a hostname is used, it must be resolvable for the service to work as expected.

HTTPS is strongly recommended. When https is used, however, it will also be necessary to include web-ssl-cert and web-ssl-key entries in the $VOLTTRON_HOME/config file:

message-bus = zmq
instance-name = my_instance
vip-address = tcp://
bind-web-address = https://<hostname>:8443
web-ssl-cert = /home/volttron/.volttron/certificates/certs/platform_web-server.crt
web-ssl-key = /home/volttron/.volttron/certificates/private/platform_web-server.pem

The vcfg tool may be used to make the changes to the $VOLTTRON_HOME/config file by choosing “Y” for the “Is this instance web enabled?” prompt. To use HTTPS, enter “https” when asked “What is the protocol for this instance?”. The vcfg tool will then give the option to generate the required SSL cert and key if these do not already exist.

(volttron) [volttron@my_instance volttron]$ vcfg

Your VOLTTRON_HOME currently set to: /home/volttron/.volttron

Is this the volttron you are attempting to setup? [Y]: y
What type of message bus (rmq/zmq)? [zmq]:
What is the vip address? [tcp://]:
What is the port for the vip address? [22916]:
What is the name of this instance? [my_instance]:
Is this instance web enabled? [N]: y
What is the protocol for this instance? [http]: https
Web address set to:
What is the port for this instance? [8080]: 8443
Would you like to generate a new web certificate? [Y]: y
WARNING! CA certificate does not exist.
Create new root CA? [Y]: y

Please enter the following details for web server certificate:
        Country: [US]:
        State: WA
        Location: MyTown
        Organization: My Organization
        Organization Unit:
Created CA cert
Creating new web server certificate.
Is this an instance of volttron central? [N]: n
Will this instance be controlled by volttron central? [Y]: n
Would you like to install a platform historian? [N]: n
Would you like to install a platform driver? [N]: n
Would you like to install a listener agent? [N]:
Finished configuration!

You can now start the volttron instance.

If you need to change the instance configuration you can edit
the config file is at /home/volttron/.volttron/config

Finally, a user must be configured in the $VOLTTRON_HOME/web-users.json file to allow authentication to the API. This file can be generated, if it does not exist, by navigating to bind-web-address/admin in a web browser and creating a user and password:

    "groups":["admin", "vui"]

Users with the “vui” claim in groups will now be able to use the API by sending requests to endpoints with paths on bind-web-address beginning with /vui. For example, where bind-web-address has been set to https://localhost:8443 the following HTTP request (with a proper HTTP Authorization Header) may be used to retrieve the root endpoint of the API:

GET https://localhost:8443/vui/

Access to the API may be disabled by removing “vui” from the list of groups in $VOLTTRON_HOME/web-users.json for any user which should not have access to the API.

Path Structure

Paths to endpoints consist of alternating constant and variable segments, and are designed to be readable and discoverable:


Get requests to non-leaf nodes typically return a route-options JSON object which gives additional possible paths within the API. For instance, a GET request send to the path /vui will return:

"route_options": {
    "platforms": "/vui/platforms"

Available Endpoints

Endpoints which are currently provided by the API are described in detail in the following sections:

  • Authentication: Endpoints for authenticating to the the API.

  • Platforms: Endpoints for working with a particular platform.
    • Agents: Endpoints for working with agents on the platform.
      • Configs: Endpoints for managing the configuration store for agents on the platform.

      • Enabled: Endpoints for enabling, disabling, and setting the start priority of agents on the platform.

      • RPC: Endpoints allowing, discovery, inspection, and calling of remote procedure calls to agents running on the platform.

      • Running: Endpoints for starting and stopping agents on the platform.

      • Status: Endpoints for determining status information for agents running on the platform.

      • Tag: Endpoints for getting, setting, and deleting the tag of agents.

    • Devices: Endpoints for getting, setting, and resetting devices on the platform.

    • Historians: Endpoints for querying data from historians on the platform.

    • Pubsub: Endpoints for subscribing and publishing to the message bus on the platform.

    • Status: Endpoints for determining and clearing the status of all agents on the platform.