Web UI

Once the server is running (see Server Setup), open its address in a browser — for example http://<host>:17800/ — to reach the Web UI. It mirrors the desktop app’s task management workflow, adapted for remote, multi-session use.

Signing in

The login screen asks for a server address (pre-filled with the current origin — leave it as-is unless you’re pointing at a different host) and an access token. On first run — when the server has not set a key yet — the page becomes an initialization wizard: set and confirm an access key (you can also generate one at random). Once a key exists, you get the normal sign-in form. The token is the key you chose during initialization, or the one shown under Settings → Security & Access (see Server Setup).

Checking “Remember this device” stores the token in localStorage (persists across browser restarts); leaving it unchecked stores it in sessionStorage (cleared when the tab closes). Nothing is ever sent anywhere except to the server itself.

Trying the public demo

A public demo instance runs at https://demo.zerx.dev/. Sign in with this shared access token:

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You must paste the token into the access token field on the login screen — the Web UI does not read a token from the page URL, so appending ?token=... to the address has no effect. Leave the server address as pre-filled.

The demo server runs in demo mode (FLUXDOWN_DEMO, see Server Setup): only a built-in generated test file can be downloaded, and since the token is public, treat everything on it as visible to and modifiable by anyone.

Main layout

The main screen is a three-pane layout, the same structure as the desktop app:

• Sidebar (left) — brand + global speed, file-type filters (All / Video / Audio / Documents / Images / Archives / Other) with live counts, queues, connection status badge, and sign-out. The queue list shows the built-in Main Queue and Download Later queues plus your named queues (create with the + button; delete a named queue from the hover trash icon — its tasks move back to the Main Queue). Each queue has a running/stopped state dot and hover buttons to start/stop it (stopping pauses every task in it and keeps them from being auto-started; starting resumes them in queue order) and to edit its daily schedule (start/stop times HH:MM — fill either or both — plus the weekdays it applies to).
• Task list (center) — top bar, batch management bar, status tabs, the virtualized task list, and a bottom status bar.
• Detail panel (right) — opens when you select a task; five tabs: General, Segments, Queue, Log, Advanced.

Top bar

• Search — filters the task list by file name. Press Ctrl+F (or Cmd+F) anywhere on the page to jump into the search box; Esc clears it.
• Batch management toggle — switches on the manage bar (checkboxes on every row).
• Pause all / Resume all — one button, its icon and action flip depending on whether any task is currently active.
• Global speed limit — shows the current limit at a glance; click it to jump to Settings to change it.
• New download — opens the new-download dialog (below).
• Settings — opens the settings screen.

Status tabs and filtering

Status tabs (All / Downloading / Completed / Paused / Error) sit above the list, each with a live count. Combine them with the sidebar’s file-type and queue filters and the search box — all four filters apply together.

Batch management

With batch management on, every row gets a checkbox, and a bar appears with Select all, a running “N selected” count, and Pause / Resume / Delete buttons that act on the whole selection at once. Deleting from here does not delete files on disk (use the detail panel’s per-task delete-with-files option for that). Click Done to exit batch mode.

Task detail panel

Selecting a task opens the detail panel:

• General — progress, downloaded/total size, speed, thread (segment) count, download URL (with copy button), save path on the server, protocol and queue, creation time. For a completed task the primary action is “Save to local” (streams the file from the server to your browser via /api/v1/tasks/{id}/file); for any other task the primary action is “Boost” (pauses other tasks to free bandwidth for this one). Delete is always available and asks for confirmation.
• Segments — the same per-segment progress visualization as the desktop app, including the live split animation when the engine proactively splits a slow segment.
• Queue — move the task between named queues.
• Log — recent events for this task.
• Advanced — checksum and per-task proxy details.

Right-clicking a row in the task list opens a context menu with the same actions (Pause/Continue/Retry, Boost, Save to local, Copy download link, Copy server file path, Move to queue…, Delete, Delete and delete files) without opening the detail panel first.

Starting a new download

The New download dialog accepts one or more URLs (one per line — HTTP, FTP, magnet links, and M3U8 playlists are all accepted) and creates one task per line. Fields:

Field	Notes
File name	Only editable for a single-URL submission; left blank it’s inferred from the URL / Content-Disposition.
Threads	Segment count: Auto (segment_advisor picks based on file size) or a fixed 1/2/4/8/16/32.
Save directory	Defaults to the server’s configured default save directory; browse the server’s filesystem with the folder-picker button next to the field (this lists directories on the server, not your local machine).
Queue	Assign to a named queue or the Main Queue.
User-Agent	Global default or one of a few presets.
Advanced (collapsible)	Cookies, Referrer, a per-task proxy URL, and a Checksum (algo=hexhash, verified after the download completes).

Two buttons submit the form: Start Download creates the task(s) and starts them right away, while Download Later creates them in a paused state parked in the built-in Download Later queue (start them individually or start that queue when you’re ready). Submitting here creates tasks directly through the management API — there is no confirmation prompt, since you’re already inside a trusted, authenticated session.

HLS quality and BitTorrent file selection

Some downloads need a decision mid-flight, delivered over the WebSocket connection:

• HLS quality — when a M3U8 playlist has multiple bitrate variants, a dialog lists each one (resolution and Mbps) with the highest-bandwidth option pre-selected. If you don’t respond within 60 seconds, the server automatically picks the highest-bandwidth variant.
• BitTorrent file selection — for torrents/magnet links with multiple files, a dialog lists every file (with size and a running “N selected / total size” readout) so you can skip files you don’t want; everything is selected by default.

These dialogs only appear while you have the Web UI open and connected — if you’re not connected when the engine needs a decision, it falls back to its default (highest HLS bandwidth after the timeout; all BT files if nothing is chosen).

Retrieving finished files

The server keeps completed files on its own filesystem. To pull one down to your local machine, use Save to local from the detail panel or the context menu — it streams the file through GET /api/v1/tasks/{id}/file as a normal browser download (with a Content-Disposition: attachment header and the original filename), authenticated via a token query parameter since browser-initiated downloads can’t set custom headers.

Settings

The settings screen (gear icon in the top bar) has seven categories:

Category	Covers
General	Server-side behavior: max concurrent tasks, default thread count, auto-retry limit and delay.
Appearance	Theme mode (Light / Dark / Follow system) and accent color — stored locally in your browser, not on the server.
Download	Default save directory and other download-engine defaults, stored in the server’s config table.
BitTorrent	librqbit engine parameters (DHT, trackers, etc.), server-side.
Proxy	Server-side outbound proxy. Unlike the desktop app, “System proxy” would require reading the server’s registry/settings, so manual proxy configuration is the practical choice here.
Security & Access	Access token (view/copy/regenerate), and toggles for the aria2-compatible RPC (/jsonrpc) and script takeover (/download) entry points, plus the current WebSocket connection status.
About	Server version, update channel, the server-side log directory (with a copy button) and a one-click Export logs as ZIP download — handy for remote/NAS troubleshooting — plus sign-out.

Each category mirrors a section of the desktop app’s settings with the same underlying config keys; for the full list of fields and their meaning see Settings in the desktop client docs.

Note that the Web UI itself has no language switcher — its interface text is fixed in Chinese regardless of the accent/theme you pick; only the desktop app has a language setting.

Connection status and reconnects

The sidebar’s connection badge shows the WebSocket state: connecting, connected (with round-trip latency), or disconnected. If the connection drops — the server restarted, the network blipped — the client automatically retries with exponential backoff starting at 1 second and doubling up to a 15-second cap, until it reconnects or you sign out. Live progress, speed, and segment updates simply resume once the socket is back; you don’t need to reload the page.