moincraft

👁️ Viewer

Prismarine Viewer architecture, version compatibility, reconnect strategy, config, and exposure warnings.

Moincraft uses a global Prismarine viewer process (bots/viewer.js) plus per-agent viewer ports for visual world state.

Architecture#

viewer.js
  → mineflayerViewer(bot, { port })
  → Express + Socket.IO
  → Browser Three.js/WebGL world view

Default config#

Variable	Purpose
`PORT=55669`	Global viewer HTTP port.
`VIEWER_USERNAME=Spectator`	Dedicated viewer bot login.
`VIEWER_VIEW_DISTANCE=8`	Chunk radius. Lower on weak hosts.
`VIEWER_RENDER_VERSION=1.21.4`	Compatibility render target.
`VIEWER_VERSION_FALLBACK=true`	Allow fallback behavior.
`VIEWER_RECONNECT_BASE_MS`, `VIEWER_RECONNECT_MAX_MS`, `VIEWER_RECONNECT_JITTER_MS`	Reconnect backoff shape.

Version compatibility#

The server is newer than Prismarine’s best-supported render version. The custom compatibility layer maps chunk/block state IDs into a supported render version and can fallback when version mismatch kicks happen.

Safety#

The viewer has no built-in authentication. Do not expose it publicly without firewall/VPN or reverse-proxy authentication.

Common issues#

Symptom	First check
Blank chunks	Bot spawned and received chunks?
Port in use	Only one viewer process? PM2/systemd/manual conflict?
Lag	Lower `VIEWER_VIEW_DISTANCE`; use dedicated spectator bot.
Duplicate login	Viewer username distinct from bot usernames?

Sources: moincraft/docs/PrismarineViewer.md, moincraft/docs/moincraft-stack-cheatsheet.md, moincraft/docs/security-hardening.md.