Settings

Open Settings with Cmd , (macOS), via the gear icon in the toolbar, or from the app menu. The window is split into a left sidebar with two groups — Preferences and System — and a content panel on the right.

Settings persist in SharedPreferences (a per-user OS-level store) so they survive restarts, app updates, and reinstalls.

Preferences → General

The General page bundles the small handful of settings most people change.

Language

The language used for menus, labels, dialogs. Probe ships with three locales:

• English — default.
• Tiếng Việt (Vietnamese).
• 日本語 (Japanese).

Technical keywords (Traffic, API, Domain, Request, Response, Headers) stay in English in every locale.

Default: English.

Theme

Value	Effect
Dark	Dark UI throughout.
Light	Light UI throughout.
System	Follow the OS appearance.

Default: Dark.

Proxy port

The TCP port the Rust proxy listens on. Probe binds 0.0.0.0:<port> so devices on your LAN can reach it.

• Range: 1024–65535.
• Default: 9099.

Changing the port restarts the proxy. The CA-cert HTTP server always listens one port below the proxy (9098 with the default), so it moves with it.

Auto-enable system proxy

When the proxy starts, Probe points your machine's network settings at itself. Turn this off to run the proxy engine only: the Composer, the WebSocket client and devices you configured by hand still go through Probe, and the rest of your machine's traffic is untouched. Probe switches the system proxy back off only if it switched it on.

Default: on.

Disable response caching

Strips If-None-Match and If-Modified-Since from outgoing requests. With this on, the server can't return 304 Not Modified and Probe always sees a body to display. Without it, conditional GETs you'd otherwise miss show as 304s with no body.

Default: off.

Auto-ignore suspected pinned hosts

When a host rejects Probe's certificate, which usually means the app pins its own, Probe passes that host through for the current session so the app keeps working. The pass-through is not saved: it ends when you quit Probe, and you can unignore the host at any time to debug it. See Pinning Detection.

Default: off, so Probe only suggests ignoring a host and you decide.

Share anonymous usage data

Sends anonymous, aggregate usage events so Probe can see which features get used. It never includes your captured traffic: no URLs, hosts, headers or bodies. The Privacy Policy lists exactly what is sent.

Default: on. Turn it off here at any time.

Quit with unsaved tabs

What Probe does when you Cmd Q with one or more dirty session tabs (tabs with captured traffic that you haven't saved).

Value	Effect
Always ask	Show the confirmation alert every time.
Save automatically	Auto-save dirty tabs and quit.
Discard automatically	Quit without saving.

The quit-confirmation alert itself has a Don't ask again checkbox: tick it before clicking Save All or Discard and Probe writes that choice into this setting, so the same action runs silently next quit. This Settings entry is how you undo that override or switch between Save and Discard later — child Settings windows stay in sync with the main window so the choice you make in either place takes effect immediately.

Default: Always ask.

Preferences → Upstream

Configure an upstream HTTP/HTTPS proxy to chain Probe in front of another proxy server (corporate proxy, region-shifting proxy, another mitm tool).

Field	What it does
Enabled	Master switch. When off, Probe connects to origins directly.
Host	Upstream proxy hostname or IP.
Port	Upstream proxy port.
TLS	Tick when the upstream is an HTTPS proxy (Probe talks TLS to the proxy itself).
Authentication	None or Basic. Basic adds the username and password as Proxy-Authorization credentials.
Bypass hosts	A text field with the placeholder "Comma-separated (e.g. localhost, 127.0.0.1, *.local)": hosts that connect directly.
Scope	Two boxes: Proxy traffic (requests captured from devices and apps) and Composer requests (manual requests from the Composer).
Test Connection	Checks that Probe can reach the proxy's host and port. It doesn't try your credentials.
Save	Stores the settings.

Changes apply to new connections right away; there's no proxy restart. With Composer requests ticked, Composer sends go straight to the upstream proxy and don't appear in the log.

Default: disabled. Reachable directly via Tools → Upstream Proxy… (Cmd Shift U).

Placeholder sections

The redesigned Settings sidebar lists five more rows that are not wired up yet and currently render a "Coming soon" page:

• Preferences → Caching — will eventually surface the same toggle as General's "Disable response caching" in a dedicated tab.
• Preferences → Notifications — OS-level notifications for capture events.
• System → Certificate — fingerprint, validity, and quick install actions for Probe's CA. For now use Certificate → Setup Guide… in the menu bar; covered in detail under Certificate Setup.
• System → Shortcuts — a future read-only reference. Use Keyboard Shortcuts instead — Probe's shortcuts are not user-customisable today.
• System → Advanced — body-size cap, strip-Accept-Encoding, data-directory display. Behaviours exist (e.g. Accept-Encoding is stripped for readable bodies), but there's no UI to tune them yet.

The CA itself lives in ~/Library/Application Support/probe_ca/ (macOS) / %LOCALAPPDATA%\Probe\probe_ca\ (Windows). Probe keeps it across launches, so once trusted on a device, it stays trusted. The one exception is a CA made by an older Probe build, which is replaced once — see Upgrading from an older build.

Storage keys

Settings are persisted by the keys defined in StorageKeys in guide_core. A few you may bump into:

Key	What it stores
app_locale	Language code (en, vi, ja).
app_theme_mode	ThemeMode enum index.
proxy_port	Integer port.
disable_caching	Boolean.
quit_with_dirty_action	ask / save / discard.
blocked_hosts	Ignored host list.
watched_domains	Domains the user has opted into full-traffic capture for.

These are reset when you uninstall or by deleting the SharedPreferences file for the app.

Resetting to defaults

There's no "Reset all" button. To start fresh:

• macOS: quit Probe, then defaults delete com.vinhtnk.mitmproxy.
• Windows: quit Probe, then delete the per-user registry key for the app under HKEY_CURRENT_USER\Software\com.guide.guideMitmProxy.

The CA certificate (in its own probe_ca folder) and your saved sessions (in ~/.probe/) are stored separately and are not reset by this.

See also

• Keyboard Shortcuts
• Certificate Setup
• Troubleshooting