Read the format before changing a value
Java NBT uses named tags with explicit types. A Byte, Int and Long can all appear as a small number on screen, yet they have different ranges and binary representations. This editor reads all twelve payload types, preserves compound order and list element types, and changes existing scalar values or numeric arrays. It does not infer a new schema or restructure a compound for you.
Choose a raw, gzip or zlib NBT file, then run the reader without edits to inspect its paths. The tool detects compression and checks the complete root, bounds and checksums. Bedrock’s little-endian variations and headers are outside this Java-only scope. Work on a copy and retain a separate backup of the world.
Use a deliberate path and value
A path such as /Data/LevelName identifies a named field. List and array indices are zero-based, so /Data/Inventory/0/Count selects the first inventory entry’s Count. A name containing / uses ~1 in its path, and a literal ~ uses ~0. The path picker displays up to 2,000 tag payloads; a full valid path can also be entered manually.
Strings use JSON quotes. Long values also use quoted decimal strings, for example "9007199254740993", because ordinary JavaScript numbers cannot represent every 64-bit integer exactly. Byte, Short and Int edits are range-checked; Float values are rounded to their actual 32-bit representation. NaN and infinite floating values are deliberately unsupported.
Review and export the right copy
The main conversion produces an NBT copy and a before/after change record. Interactive workbench edits have their own download buttons; the original report remains a snapshot of the initial run. Review the selected path and type before downloading, and keep the change record beside the original file.
Java strings use modified UTF-8. NUL, Turkish text and supplementary characters are handled explicitly rather than replaced. A valid binary result still does not guarantee that an application accepts the edited value. Close the game before replacing files, and test a separate copied world with the matching Java version.