LagMap

LagMap is a lightweight Paper server plugin that turns chunk performance data into an interactive in-game heatmap.

Instead of digging through long profiler outputs or console logs, server administrators can open /lagmap and immediately see which nearby chunks are likely contributing the most load.

Features

• Interactive 9×5 chunk heatmap

• Chunk Heat Score from 0–100

• Color-coded load levels:

  • Green – Cool
  • Yellow – Warm
  • Orange – Hot
  • Red – Severe

• Detailed chunk inspection

• Tracks:

  • Entities
  • Villagers
  • Hoppers
  • Block Entities
  • Dropped Items
  • Redstone Activity

• Server status with:

  • TPS
  • MSPT
  • Online Players

• Refresh and recenter controls

• Safe teleportation to selected chunks

• Configurable scoring weights and thresholds

• Lightweight caching and request deduplication

• Progressive chunk scanning to avoid performance spikes

Performance First

LagMap is designed to avoid becoming part of the problem it is trying to diagnose.

It:

• NEVER loads or generates chunks just to analyze them!!!
• Does not scan entire chunks block-by-block!
• Uses a configurable per-tick scan budget
• Deduplicates repeated scan requests
• Uses bounded caches and cleanup
• Uses only public Paper APIs

Heat Score

LagMap 0.1.0 uses a heuristic Heat Score based on measurable chunk characteristics and activity.

The score helps identify suspicious or unusually busy chunks quickly.

It is NOT an exact measurement of per-chunk CPU usage!!!

Commands

/lagmap Opens the interactive chunk heatmap.

/lagmap reload Reloads the LagMap configuration.

Permissions

lagmap.use Allows access to the LagMap interface.

lagmap.reload Allows configuration reloads.

lagmap.teleport Allows teleportation to selected chunks.

Requirements

• Paper 26.2+
• Java 25

Roadmap

Future versions are planned to expand LagMap!

AI Disclosure

Generative AI tools were used as part of the development workflow.