Flashback Server

Server-side Flashback replay recording for Paper — zero dependencies, Folia-ready, with a clip system.

Flashback Server is a Paper plugin that records gameplay into Flashback-format replays entirely server-side — no client mod required for the players being recorded. Drop the jar in /plugins, and you're recording.

Features

• Record any player server-side — replays are saved as .flashback files readable by the Flashback client mod.
• Clip system — maintain a rolling buffer for a player and save the last N seconds on demand or automatically on death.
• Auto-clip on death — optionally save a clip whenever an armed player dies (config toggle).
• Folia-ready — works on the regionized Paper fork with no extra configuration.
• Zero dependencies — pure Netty packet capture; no ProtocolLib to break on every update.
• Renderable snapshots — each recording includes a synthesized initial-state snapshot (registries, chunks, player state) so the Flashback client can render it correctly.

Why another replay plugin?

	Flashback Server	Paper Flashback	server-replay
Platform	Paper/Folia 1.21.5–1.21.11	Paper	Fabric
ProtocolLib required	❌ No	✅ Yes	—
Folia support	✅ Yes	❌ No	—
Clip system (save last N seconds)	✅ Yes	❌ No	❌ No
Output format	.flashback	.flashback	.mcpr + Flashback

Installation

1. Requires Paper (or a Paper fork such as Folia) for Minecraft 1.21.5–1.21.11.
2. Drop FlashbackServer-*.jar into your server's plugins/ folder.
3. Restart the server. No additional dependencies needed.
4. View recorded replays with the Flashback client mod.

Commands

All commands require the permission flashbackserver.replay (default: op).

Command	Description
/replay start players <player>	Start recording a player
/replay stop players <player>	Stop recording and save → plugins/FlashbackServer/replays/<name>-<uuid>.flashback
/replay clip arm <player>	Start a rolling clip buffer for a player
/replay clip disarm <player>	Stop and discard the rolling clip buffer
/replay clip save <player>	Save the current clip → plugins/FlashbackServer/clips/<name>-clip-N.flashback
/replay verify <file>	Decode-check a saved replay file (admin/diagnostic)
/replay help	Show the in-game help

Tab-completion is supported for all subcommands and online player names.

Configuration

plugins/FlashbackServer/config.yml is generated on first launch:

clips:
  # Length of the rolling clip buffer, in seconds.
  # The actual saved clip will be approximately window-seconds..2×window-seconds
  # due to keyframe granularity.
  window-seconds: 30

  # Automatically save a clip when an armed player dies.
  # Requires clips to be armed for the player (/replay clip arm <player>).
  auto-clip-on-death: true

Key	Default	Description
clips.window-seconds	30	Rolling clip length in seconds
clips.auto-clip-on-death	true	Save a clip automatically when an armed player dies

How it works (briefly)

Flashback Server captures raw Minecraft packets directly at the Netty layer. When a recording starts, it injects a channel handler into the player's pipeline and captures all outbound packets. Before appending live traffic, it synthesizes an initial-state snapshot (registry data, surrounding chunks, and current player state) so the Flashback client has everything it needs to render the replay from the beginning. Long recordings roll over to a new chunk automatically, and dimension changes trigger a fresh snapshot.

Compatibility

• Minecraft 1.21.5–1.21.11
• Paper and Paper forks (Purpur, Pufferfish, Folia)
• Replays are viewed with the Flashback client mod

Flashback Server is an independent project and is not affiliated with or endorsed by the Flashback mod or its author. It produces files compatible with the Flashback format for interoperability.

Status

Core recording, clip, and verify features are shipped. Visual rendering should be confirmed in the Flashback client against your specific server version.

Telemetry

Flashback Server collects anonymous, opt-out usage telemetry to help improve the plugin. No player data (names, UUIDs, IPs) is ever collected.

What is sent:

Event	Properties
plugin_enabled	Server platform (Paper/Folia), server version, Minecraft version, plugin version
recording_saved	File size in bytes
recording_failed	Exception class name only (e.g. IOException)
clip_saved	File size in bytes
clip_failed	Exception class name only

All events are sent to PostHog and include an anonymous server-scoped random UUID (stored in plugins/FlashbackServer/.telemetry-id) — it is not linked to any player or operator identity.

To disable, set in plugins/FlashbackServer/config.yml:

telemetry:
  enabled: false

License

MIT