LagPeek
One command that tells you why your server is lagging.
LagPeek is a tiny, read-only diagnostic tool for Paper servers. Run one command, get an instant snapshot — no setup, no config, no background tasks.
What it shows
Run /lagpeek and you get:
- TPS — 1 / 5 / 15 minute averages, color-coded (green = fine, yellow = struggling, red = lagging)
- Memory — heap used / allocated / max, in MiB
- Chunks — how many chunks are loaded, per world
- Entity hotspots — the top entity types on your server, plus the 10 worst single chunks (entity type, count, and coordinates so you can teleport straight to the problem)
Typical use: server feels laggy → /lagpeek → "oh, 900 zombies in one chunk at ~1240, -380" → go fix it.
Install
- Drop
lagpeek-x.y.z.jarinto yourplugins/folder. - Restart the server. Done — there is nothing to configure.
Requires Paper 1.21.x (or a fork) and Java 21.
Command & permission
| Command | Permission | Default |
|---|---|---|
/lagpeek |
lagpeek.use |
OP |
Safe by design
LagPeek only reads server state. It has no event listeners, never edits the world, and runs no repeating tasks — so it cannot conflict with any other plugin. The only network/background activity is a one-time update check on startup (against Modrinth's public API, notify-only) and anonymous bStats usage stats.
Building from source
./gradlew :lagpeek:build
Output: lagpeek/build/libs/lagpeek-<version>.jar
