I started a webui container and then I started to get this error in OpenWebUI interface.

SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

  • latest Ollama on windows
  • latest Open WebUI in docker desktop

according to a post online, I should set ENABLE_WEBSOCKET_SUPPORT=True in my docker compose, but I’m not using reverse proxy. Is ENABLE_WEBSOCKET_SUPPORT=True necessary?

What could a possible solution be for this?

My docker compose

services:
  open-webui:
    image: ghcr.io/open-webui/open-webui:cuda 
    container_name: open-webui
    restart: unless-stopped
    ports:
      - "3000:8080"
    extra_hosts:
      - "host.docker.internal:host-gateway"
    volumes:
      - ./data:/app/backend/data
    deploy:
      resources:
        reservations:
          devices:
            - driver: nvidia
              count: all
              capabilities: [gpu]
volumes:
  open-webui:

log

2025-06-21 10:43:57 open-webui  | 2025-06-21 00:43:57.601 | INFO     | uvicorn.protocols.http.httptools_impl:send:476 - 172.21.0.1:37276 - "GET /_app/version.json HTTP/1.1" 304 - {}
2025-06-21 10:44:58 open-webui  | 2025-06-21 00:44:58.114 | INFO     | uvicorn.protocols.http.httptools_impl:send:476 - 172.21.0.1:49064 - "GET /_app/version.json HTTP/1.1" 304 - {}
2025-06-21 10:45:58 open-webui  | 2025-06-21 00:45:58.779 | INFO     | uvicorn.protocols.http.httptools_impl:send:476 - 172.21.0.1:55958 - "GET /_app/version.json HTTP/1.1" 304 - {}
2025-06-21 10:46:59 open-webui  | 2025-06-21 00:46:59.179 | INFO     | uvicorn.protocols.http.httptools_impl:send:476 - 172.21.0.1:47424 - "GET /_app/version.json HTTP/1.1" 304 - {}

UPDATE:

  • when I open http://localhost:3000/ in another browser it works perfectly fine. I think the issue is about the browser I used (firefox with a lot extension installed and setting tweaked)

UPDATE 2: The problem is with this plugin https://addons.mozilla.org/en-US/firefox/addon/chameleon-ext/ Everything works fine with it disabled.

The reason my chameleon breaks openwebui is because I changed a setting in it that it blocks all websocket connection

Thank you everyone for your help