NBT Editor — Typed Java Data & Region Backup Tools
Inspect and edit Java NBT locally with exact 64-bit values, typed paths and a change record. Inspect MCA region slots or copy selected verified chunks from a real backup.
NBT Workshop
Work on a copy. This tool cannot invent missing world data.
Supported scope: Java only · NBT 16 MiB expanded · MCA 32 MiB · no Bedrock/LZ4
Java NBT or region files
Required fields are marked with an asterisk.
Typed data and bounded checks
Review your output, then save it to your device.
Make the next step clear.
Your findings, assumptions and next steps will appear here after you run the check.
NBT Workshop · https://nbt.kitforma.com/ · KitForma
Exact 64-bit values and explicit tag types
Local path edits with a before/after record
Selective real-backup chunk restore with untouched sectors retained
Understand the evidence.
Focused guides explain the rules, the edge cases and the checks worth doing before you act.
Edit Java NBT without changing numeric types
Use typed paths, exact Long strings and a new output copy to make a controlled Java NBT edit.
Read the guide ↗Field guide / 02Inspect Java Anvil region slots and chunk envelopes
Separate header allocation checks from actual NBT decoding and understand what a region inspection proves.
Read the guide ↗Field guide / 03Restore selected chunks from a real Java region backup
Copy verified backup records while preserving unselected data and reporting the limits of a partial restore.
Read the guide ↗Before you start
Does this support Bedrock Edition?
No. It supports Java big-endian named NBT and bounded Java Anvil MCA inspection. Bedrock little-endian NBT, LevelDB worlds and .mcworld packages are outside scope.
Are 64-bit Long values exact?
Yes. Long and LongArray values are represented as signed decimal strings in the editor and written as exact 64-bit integers. Enter them with JSON quotes.
Can I change tag types or add new structures?
This release edits existing scalar values and numeric arrays while preserving compound/list structure and tag types. Use a valid existing path; it does not invent a Minecraft schema.
Can it recover chunks without a backup?
No. It can copy selected valid chunks from an actual backup into a new region file. Missing or overwritten content cannot be reconstructed from nothing.
Are unselected chunks changed during restore?
Their header entries and all original sectors are retained byte-for-byte. New backup records are appended and only selected slot locations/timestamps are updated. Remaining corruption and cross-world consistency are not automatically repaired.
What are the limits and privacy rules?
Files stay on your device. NBT is limited to 8 MiB compressed, 16 MiB expanded, 64 nesting levels, 100,000 tag payloads and 500,000 entries per numeric array. MCA files are limited to 32 MiB; restore supports 1–32 selected slots. External .mcc and LZ4 chunks, duplicate names and non-finite floats are unsupported.
Sources & assumptions
Formats, algorithms and supported features are documented below. Check the stated scope and inspect your output before using it.
- Java DataInput modified UTF-8 ↗
Java modified UTF-8 encodes NUL and supplementary characters differently from standard UTF-8.
- Prismarine NBT format implementation ↗
Independent reference for NBT type and compression handling; this tool uses its own bounded reader/writer.
- Prismarine Anvil region implementation ↗
Independent technical reference for Java region/chunk storage.
Reviewed 2026-10-17. Read our methodology or report an issue.