Web Interface

info

The web interface lets you use opencode from a browser, making it accessible on machines where installing the full TUI is impractical -- such as tablets, shared workstations, or remote servers.

Starting the Web Server

Launch the web interface:

opencode web

This starts an HTTP server and automatically opens the web interface in your default browser. By default it listens on http://localhost:3000.

Specifying Port and Hostname

opencode web --port 8080 --hostname 0.0.0.0

Flag	Default	Description
--port	3000	TCP port to listen on
--hostname	localhost	IP address to bind to
--mdns	true	Enable mDNS advertising
--mdns-domain	"local"	mDNS domain suffix
--cors	unset	CORS origin (e.g., * or http://example.com)

Binding to All Interfaces

To allow connections from other machines on your network:

opencode web --hostname 0.0.0.0

warning

Security note: When binding to 0.0.0.0, set OPENCODE_SERVER_PASSWORD to require authentication (see below).

mDNS Discovery

With mDNS enabled (default), the server advertises itself on the local network as opencode.local. Other machines on the same network can discover and connect to it by browsing for _opencode._tcp services.

Disable mDNS if you don't need it:

opencode web --mdns false

Web Interface Features

The web UI mirrors most of the TUI's functionality:

• Chat interface with conversation history
• File references with @ fuzzy search
• Slash commands (/init, /connect, /undo, /share, etc.)
• Agent mode switching (Build / Plan)
• Image upload support
• Session management
• Theme selection
• Syntax-highlighted code display
• File diff viewer

Some TUI-specific features (like custom keybinds) are not available in the web interface.

CORS Configuration

When connecting to the web server from browser-based clients on different origins, configure CORS:

opencode web --cors "*"

Or restrict to a specific origin:

opencode web --cors "https://myapp.example.com"

CORS can also be configured in your opencode JSON config:

{
  "web": {
    "port": 3000,
    "hostname": "0.0.0.0",
    "cors": {
      "origin": "*"
    },
    "mdns": true,
    "mdnsDomain": "local"
  }
}

Attaching TUI to Web Backend

You can run the web server as a backend and attach the TUI to it. This lets you use the terminal UI while the web interface is also available.

Start the Backend Server

opencode serve

This runs a headless server on port 4096 by default.

Attach the TUI

opencode attach http://localhost:4096

Now both the TUI and web interface share the same session context. Changes made in one are reflected in the other.

Remote Attach

Connect to a server on another machine:

opencode attach http://192.168.1.100:4096

If the remote server has password authentication:

opencode attach http://opencode:password@192.168.1.100:4096

Send Prompts Non-Interactively

You can also send prompts to the server without a TUI:

opencode run --attach http://localhost:4096 "Add error handling to the login form"

Headless API Server

For programmatic access, use opencode serve to start a headless server:

opencode serve --port 4096

The server exposes a REST-like API. Available endpoints:

POST /api/chat

Send a message:

{
  "message": "Explain the project structure",
  "sessionId": null,
  "mode": "build"
}

Response:

{
  "sessionId": "abc123",
  "response": "This project is a React application...",
  "files": ["src/App.tsx", "src/components/"]
}

GET /api/sessions

List sessions:

{
  "sessions": [
    { "id": "abc123", "project": "/home/user/my-app", "model": "claude-sonnet-4-20250514", "createdAt": "2026-05-20T10:00:00Z" }
  ]
}

GET /api/sessions/:id

Get session details and history.

DELETE /api/sessions/:id

Delete a session.

Comparison: web vs serve vs TUI

Feature	opencode (TUI)	opencode web	opencode serve
Interface	Terminal UI	Browser UI	None (API only)
Keybinds	Full support	Limited	N/A
Custom themes	Full support	Built-in only	N/A
File system access	Direct	Via server	Via server
Image support	Drag & drop	File upload	Via API
Remote access	No (local terminal)	Yes	Yes
Auth	OS-level	HTTP Basic	HTTP Basic
Multiple clients	No	Yes	Yes
CI/CD usage	No	No	Yes

What's Next

• Terminal UI -- Full TUI reference
• CLI Usage -- Non-interactive CLI mode
• IDE Integration -- Editor workflows
• Configuration -- Server configuration in opencode.json