# How to launch prebuilt OpenEMS UI? **URL:** \ **Category:** English Forum\ **Created:** [April 21, 2026, 8:05pm UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819 "2026-04-21T20:05:20Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![mzenker](https://community.openems.io/letter_avatar_proxy/v4/letter/m/5daacb/32.png) [@mzenker](https://community.openems.io/u/mzenker)\ **Post date:** [April 21, 2026, 8:05pm UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819/1 "2026-04-21T20:05:21Z")
Hi there, I am new to OpenEMS and would like to try the simulated test system as described in the Getting Started guide on a Laptop running Debian Linux. I have installed Java 21, started Edge and configured following the guide, including the websocket server on port 8085. Now I am stuck at the section “3. Run OpenEMS UI”. I have downloaded openems-ui.tar.xz from [here](https://github.com/OpenEMS/openems/releases/) and extracted it. But how do I start the UI? This is not described in the guide. It only says: 1. Make sure OpenEMS Edge is running locally and the websocket is running on port `8085`. 2. Open the UI URL 3. You should see OpenEMS UI. It does not say what the URL is or what else I have to do to run the UI. Apparently I am missing something. localhost:4200 says “connection failed”. In some forum posts it says that a webserver is needed - additionally to the webserver run by Edge? Also the information I found is related to building the UI using VSCode. As I am not planning to develop on the UI, I would like to use the prebuilt version. I would be grateful for the information missing in the Getting Started Guide, or a hint where I can find it. If need be I do volunteer to make a PR to improve the Getting Started guide section. Thank you! Matthias ---
**Author:** ![S1m0n](https://community.openems.io/letter_avatar_proxy/v4/letter/s/5f8ce5/32.png) [@S1m0n](https://community.openems.io/u/S1m0n)\ **Post date:** [April 22, 2026, 8:49pm UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819/2 "2026-04-22T20:49:04Z")
Dear Matthias Would it be an option for you, to run the UI in a docker? (Thats what I do, when testing on my Raspberry Pi). You could look here: [Deploy the UI with Docker :: Open Energy Management System](https://openems.github.io/openems.io/openems/latest/ui/deploy.html). There you can see in the docker-compose.yml that the container is listening on port 4200. This should allow to reach the ui with a browser on “url:4200”. Or if you like, I am also happy to share my docker-compose.yml. BR, Simon ---
**Author:** ![ostkamp](https://community.openems.io/letter_avatar_proxy/v4/letter/o/df788c/32.png) [@ostkamp](https://community.openems.io/u/ostkamp)\ **Post date:** [April 23, 2026, 9:44am UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819/3 "2026-04-23T09:44:22Z")
Hi Matthias, I would also recommend the docker way outlined by S1m0n. It is very easy to use. I recommend to install the original docker instead of using some stuff provided by the distribution. Unfortunately this forum refuses to let me post a link to the page describing it. You can easily find it if you do a Google search with keywords “Docker install debian” ---
**Author:** ![mzenker](https://community.openems.io/letter_avatar_proxy/v4/letter/m/5daacb/32.png) [@mzenker](https://community.openems.io/u/mzenker)\ **Post date:** [April 23, 2026, 10:04pm UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819/4 "2026-04-23T22:04:49Z")
Hi, thank you S1m0n and ostkamp for your replies. To be honest, I have never worked with docker and do not really see why I should add a level of complexity here. In the meantime, I have managed to get OpenEMS working on my Debian laptop using the prebuilt packages for Edge and UI. I found the missing information in the (german) forum, especially in [UI am Raspberry konfigurieren - #3 by windpower](https://community.openems.io/t/ui-am-raspberry-konfigurieren/72/3) . So from my point of view the additional steps not mentioned in section 3 of the Getting Started guide (for Linux) are: - Go to [Releases · OpenEMS/openems · GitHub](https://github.com/OpenEMS/openems/releases/) and download the latest openems-ui.tar.xz - Extract it to a local directory on your local machine (e.g. /home/user/openems/openems-ui) - To run the UI, you need a web server. In the following, nginx is assumed, but another webserver (e.g. Apache) may also be used. - Install nginx - Create a file /etc/nginx/conf.d/openems\_nginx.conf with the following contents: > `server {` > ` listen 4200;` > ` server_name openems;` > > ` # OpenEMS Web-Interface` > ` location / {` > ` root /home/user/openems/openems-ui;` > ` index index.html index.htm;` > > ` error_page 404 300 /index.html;` > ` }` > > `}` - Start nginx - Open localhost:4200 in a browser. You can also open 192.168.xx.yy:4200 from a remote machine, where 192.168.xx.yy is the IP address of the machine running OpenEMS. To get the UI to run, I needed the following additional steps: - If there are error messages saying that port 80 is already used (this was the case on my machine as Apache was installed by default): Remove /etc/nginx/sites-enabled/default. This is a link to /etc/nginx/sites-available/default where port 80 is configured to be used. - If the browser shows “403 forbidden”, this may be due to missing permissions. All directories on the path to the openems-ui need to have read and execute permissions. You can check this with the command `namei -l /home/user/openems/openems-ui.`For example, /home/user might have “rwx” permissions only for user. In that case, the command chmod a+rx /home/user changes the permissions, so that nginx can run openems-ui. - The Controller API Websocket port needs to be set to 8075 (instead of 8085) as the prebuilt version of the UI seems to be compiled for this port, see [Ui bauen und installieren - #4 by stefan.feilmeier](https://community.openems.io/t/ui-bauen-und-installieren/1351/4) . I hope this information helps someone. Question to the OpenEMS team: Do you want me to add it to the Getting Started guide with a pull request? Matthias ---
**Author:** ![sjjh](https://community.openems.io/user_avatar/community.openems.io/sjjh/32/2296_2.png) [@sjjh](https://community.openems.io/u/sjjh)\ **Post date:** [April 25, 2026, 4:12pm UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819/5 "2026-04-25T16:12:15Z")
> [@mzenker](#): > > Question to the OpenEMS team: Do you want me to add it to the Getting Started guide with a pull request? Not being part of the OpenEMS team, but please create a PR. ---
**Author:** ![mzenker](https://community.openems.io/letter_avatar_proxy/v4/letter/m/5daacb/32.png) [@mzenker](https://community.openems.io/u/mzenker)\ **Post date:** [April 28, 2026, 9:54pm UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819/6 "2026-04-28T21:54:12Z")
I would love to, but I did not manage to do so. I cloned the OpenEMS repo and added my stuff to the documentation. Then I created a new branch using the git extension of VSCodium and committed my changes. When I tried to push to origin, I get an error message saying that I do not have permissions to push to OpenEMS/openems. What do I do wrong? ---
**Author:** ![sjjh](https://community.openems.io/user_avatar/community.openems.io/sjjh/32/2296_2.png) [@sjjh](https://community.openems.io/u/sjjh)\ **Post date:** [April 28, 2026, 10:12pm UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819/7 "2026-04-28T22:12:09Z")
Please do not try to push directly to the repository, but create a [pull request (PR)](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request). ---
**Author:** ![mzenker](https://community.openems.io/letter_avatar_proxy/v4/letter/m/5daacb/32.png) [@mzenker](https://community.openems.io/u/mzenker)\ **Post date:** [April 28, 2026, 11:07pm UTC](https://community.openems.io/t/how-to-launch-prebuilt-openems-ui/10819/8 "2026-04-28T23:07:17Z")
That is what I intended to do, so I created a local branch and committed there. But to make a PR, I thought I needed to push the branch to the OpenEMS repo, which I don’t have permission to do. Then from a [link](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request-from-a-fork) on the page you indicated, I learned that I can create a fork on my own GitHub space and make the PR from there. So I did that, it can be found [here](https://github.com/OpenEMS/openems/pull/3702). Now it needs review, but I don’t manage to request a review from there, maybe also due to insufficient permissions. So if someone with appropriate permissions is reading this, please feel free to look at it. 🙂