waybar-niri-window(5) File Formats Manual waybar-niri-window(5)

# [NAME](#NAME)

waybar - niri window module

# [DESCRIPTION](#DESCRIPTION)

The **window** module displays the title of the currently focused window in niri.

# [CONFIGURATION](#CONFIGURATION)

Addressed by **niri/window**

**format**:  
typeof: string  
default: {title}  
The format, how information should be displayed. On {} the current window title is displayed.

**rewrite**:  
typeof: object  
Rules to rewrite window title. See **rewrite rules**.

**separate-outputs**:  
typeof: bool  
Show the active window of the monitor the bar belongs to, instead of the focused window.

**icon**:  
typeof: bool  
default: false  
Option to hide the application icon.

**icon-size**:  
typeof: integer  
default: 24  
Option to change the size of the application icon.

**expand**:  
typeof: bool  
default: false  
Enables this module to consume all left over space dynamically.

# [FORMAT REPLACEMENTS](#FORMAT_REPLACEMENTS)

See the output of "niri msg windows" for examples

**{title}**: The current title of the focused window.

**{app\_id}**: The current app ID of the focused window.

# [REWRITE RULES](#REWRITE_RULES)

**rewrite** is an object where keys are regular expressions and values are rewrite rules if the expression matches. Rules may contain references to captures of the expression.

Regular expression and replacement follow ECMA-script rules.

If no expression matches, the title is left unchanged.

Invalid expressions (e.g., mismatched parentheses) are skipped.

# [EXAMPLES](#EXAMPLES)

```
"niri/window": {
	"format": "{}",
	"rewrite": {
		"(.*) - Mozilla Firefox": "🌎 $1",
		"(.*) - zsh": "> [$1]"
	}
}
```

# [STYLE](#STYLE)

- **#window**
- **window#waybar.empty #window** When no windows are on the workspace

The following classes are applied to the entire Waybar rather than just the window widget:

- **window#waybar.empty** When no windows are in the workspace
- **window#waybar.solo** When only one window is on the workspace
- **window#waybar.<app-id>** Where **app-id** is the app ID of the only window on the workspace

2026-10-30

---

Document: waybar-niri-window(5) from waybar 0.15.0-r2 (Chainguard OS)