Your file never leaves your computer. The whole inspection runs in your browser, and this page makes no network request that contains your file. This tool reads only; it never writes your world.
level.dat is the small gzip-compressed NBT file at the root of every Minecraft world folder. It holds the world's identity: its seed, the version that wrote it, the spawn point, the time of day, the weather, the difficulty and hardcore flags, every game rule, and the list of data packs. This inspector reads all of that and shows it in plain language without touching the file.
When Minecraft saves a world it writes the chunks into region files, the player into either level.dat or a playerdata file, and everything that describes the world as a whole into level.dat. Because it is a single small file, it is the fastest place to look up a fact about a world without loading the world itself. The most common reason people open it is to recover the seed, but it also answers questions like which version made this save, where the world spawn is, and which game rules were changed from default.
The file is stored as NBT, a binary tag format, wrapped in gzip. That is why a text editor shows only garbled bytes. The inspector above decompresses it and walks the tag tree in your browser, so you get a readable view in a second without installing an NBT editor.
These are the fields the inspector pulls out of the Data compound. Minecraft has moved several of them across versions, so the tool tries the modern location first and falls back to the classic one.
If a field is missing, the inspector says so instead of inventing a value. That keeps the read honest: what you see is exactly what is in your file.
Recovering a seed you forgot is the most common use. The whole job takes under a minute:
1. Open your saves folder and find the world. On Windows, press Win and R, type %appdata%\.minecraft\saves and open the world's folder.
2. Drop the file named level.dat onto the inspector above, or click to browse for it.
3. Read the Seed row and use the copy button to grab it.
4. To regenerate the terrain, start a new world, open More World Options, and paste the number into the Seed field. The same seed and version produce the same terrain.
You can also read the seed in game with the /seed command if cheats are on, but level.dat works even when you cannot open the world, for example on a save copied from a friend or pulled off a dead server.
Once you have the number, you can do more with it than regenerate the terrain. Paste it into a Minecraft seed map to see every biome and structure in your world on one map, so you know where the nearest village, stronghold, or mushroom island is without scouting a single chunk.
Drop the level.dat into the inspector above. On most versions the seed sits at Data.WorldGenSettings.seed and the tool reads it straight out. Newer worlds moved it to data/minecraft/world_gen_settings.dat in the world folder, and the inspector asks for that file when it sees that layout. Either way you get the number with a copy button, ready to paste into the Seed box on the Create New World screen.
It sits in the world's save folder. On Windows that is %appdata%\.minecraft\saves\<world name>\level.dat, on macOS it is ~/Library/Application Support/minecraft/saves/<world name>/level.dat, and on Linux it is ~/.minecraft/saves/<world name>/level.dat. Pick the file named level.dat, not level.dat_old or the session.lock file.
No. The level.dat is read, gunzipped, and parsed entirely in your browser, and this page makes no network request that contains your file. The inspector is read only, so it never writes anything back to your world. To edit the file, use a dedicated editor instead.
Two reasons. Very old saves stored it elsewhere and some superflat or custom worlds omit it. More often the world is a recent one that keeps world gen settings, game rules, weather, the day clock and the border in their own files rather than in level.dat, and the inspector will show a panel asking you to add those. It says which is the case rather than guessing.
The inspector compares each rule stored in your world against the vanilla default. A rule shown as changed has a value different from the default, and the default is listed next to it. Use the Only changed filter to see at a glance what was tweaked, for example keepInventory turned on or doDaylightCycle turned off.
Yes. The inspector handles both the classic layout, where the spawn lives in SpawnX, SpawnY, and SpawnZ and difficulty is a single value, and the newer layout used since 1.21 and 26.x, where the spawn and difficulty moved into their own compounds. The version name and data version from the file are shown so you know which release wrote it.
Want to change a flag instead of just reading it? Or browse more Minecraft tools:
