Datapack Sandbox

Verify datapack behavior without starting a server

A clean-room local runtime for Minecraft Java datapacks. Run functions, inspect resources, inject player events, and lock world state down with repeatable assertions.

Start in 5 minutes

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Datapack Sandbox cube and command prompt mark

ONE RUNTIME · THREE WORKFLOWS

Move from an idea to a reproducible test

Use the same deterministic runtime from the terminal, a manifest suite, or your JVM tests. Reports share the same outputs, traces, diagnostics, and snapshots.

01
Load
Read packs and version-specific resource formats.
02
Run
Execute commands, functions, ticks, and player events.
03
Assert
Compare observable output and world state.

manifest regression26.2

$ dps check --strict examples

loading 7 manifests · profile 26.2

PASS generator-output.dps.json

PASS player-events.dps.json

PASS full-stack.dps.json

ALL CHECKS PASSED

4commands2outputs7state changes

DESIGNED FOR TRUST

Fast feedback without pretending to be a server

Datapack Sandbox is intentionally explicit about what it models. Use it for deterministic development feedback, then reserve vanilla integration runs for behavior that genuinely requires the game engine.

Deterministic

Stable seeds, snapshots, and structured reports make failures reproducible.

Inspectable

Every command can expose source locations, output events, traces, and state diffs.

Version-aware

Built-in profiles cover modern datapack formats from 1.20.4 through 26.2.

Start with one command

Run a `.mcfunction`, direct command, or complete datapack without waiting for a vanilla server to boot.

Choose an entry point

Turn world state into assertions

Check scores, storage, entities, players, output events, traces, and snapshot diffs.

Design regression tests

Know the simulation boundary

Commands and resources are labeled modeled, partial, or unsupported so approximations never masquerade as vanilla behavior.

Read the support matrix

Fit into JVM test suites

Write Kotlin or Java QuickTests, or connect the CLI and manifest runner to CI.

Open the code test API