RiftSentry

Windows overlay for manually tracking enemy summoner spell cooldowns in League of Legends. It reads match context from Riot’s Live Client Data API (localhost) and spell metadata from Data Dragon. Timers start only when you click a spell button.

The app also supports an optional sync lobby mode. Players can point the overlay at a self-hosted sync server, create a lobby with a 6-digit code, or join an existing lobby to share cooldown and Cosmic Insight state in real time.

Requirements

• Windows
• .NET 8 SDK
• League of Legends client running; during a match the Live Client API must be available on https://127.0.0.1:2999

Build

dotnet build RiftSentry.sln -c Release

Build sync server

dotnet build src/RiftSentry.SyncServer/RiftSentry.SyncServer.csproj -c Release

Run

dotnet run --project src/RiftSentry/RiftSentry.csproj

Or run RiftSentry.exe from src/RiftSentry/bin/Release/net8.0-windows/ after a Release build.

Run sync server locally

dotnet run --project src/RiftSentry.SyncServer/RiftSentry.SyncServer.csproj

By default the SignalR hub is exposed at http://localhost:5012/syncHub when running from dotnet run, or at http://localhost:8080/syncHub when running in Docker.

Health endpoint:

GET /health

Run sync server with Docker

docker compose up --build -d

This starts the self-hosted sync server on port 8080.

GitHub release

Push a version tag (for example v1.0.0). The Release workflow attaches two zips:

• RiftSentry-win-x64-self-contained.zip — single .exe, no .NET install. Built as a compressed single-file app with full globalization support so the WPF settings UI works correctly on packaged builds.
• RiftSentry-win-x64-framework-dependent.zip — tiny footprint; requires the .NET 8 Desktop Runtime (Windows x64 under Run desktop apps).

The large size you see on a plain self-contained publish is mostly the .NET runtime embedded in the app. Publish trimming is not a good fit for WPF in most cases.

How it works

• Live Client (/liveclientdata/allgamedata, polled every 2 seconds): detects your team, lists enemy champions, items (Ionian Boots), and summoner spell slots.
• Data Dragon: loads the current patch from versions.json, then summoner.json and champion.json for cooldowns and icons.
• Assets: downloaded spell and champion PNGs are cached under assets next to the executable (AppContext.BaseDirectory).
• Overlay: borderless, transparent, topmost WPF window. It shows only while a match is detected; otherwise the window stays hidden. A system tray icon is always available; right-click Exit to quit.
• Settings: a tray Settings window lets you save the sync server URL, create a lobby, join by 6-digit code, and leave the current lobby.
• Haste: Ionian Boots (+12) is read from items. Cosmic Insight (+18) is detected when the Live Client exposes full enemy rune data; otherwise use the C toggle per row.
• Cooldown formula: baseCooldown * (100 / (100 + totalSummonerSpellHaste)).

Sync lobbies

• The saved server URL is persisted under the current Windows user profile.
• The active lobby code is never persisted.
• The lobby owner creates a room and shares the generated 6-digit code.
• Other players join with the same server URL and code.
• Spell cooldown clicks and manual Cosmic Insight toggles are broadcast to every connected player in that lobby.
• Late joiners receive the current synced state, including active cooldown timers.
• If a player is no longer in the same game as the lobby owner, the sync server disconnects that player from the lobby.
• If the owner leaves the game or disconnects, the lobby closes for everyone.

Manual tracking

RiftSentry does not detect spell casts automatically. You click a spell when you see it used; click again during the timer to reset.

Application icon

Place app.ico next to src/RiftSentry/RiftSentry.csproj. The project references it via <ApplicationIcon>app.ico</ApplicationIcon>.

Compliance note

Use only supported interfaces (Live Client API + public static data). This tool is intended as a manual aid similar to noting timers yourself. Follow Riot’s current policies for third-party tools.