Fast NBT
ModSpeeds up world loading and saves by handling data faster.
Why gradeB
How grades workStrengths
Points lost
- Releases in only 2 of the last 24 months−5 points
- First release only 7 months ago−3 points
- Some modpacks removed it−1 point
All 11 criteria
Maintenance
5 points lost22 / 27Last releaseHow long ago the newest file came out, or an existing file was marked as working on a new Minecraft version.5 weeks ago (19 Sep 2026) 12 / 12Supports popular versionsWhether the project has a file for a Minecraft version that 15% or more of the popular mods updated in the last 6 months also support. A version many modpacks use, like 1.20.1 or 1.21.1, also counts after a release in the last 12 months.1.21.1 on NeoForge, 1.20.1 on Forge. 15% or more of the popular mods updated in the last 6 months also have files for 1.21.1. Latest Minecraft: 26.3. 9 / 9Regular releasesIn how many of the last 24 months a new file came out. Full points at 8 months.Releases in 2 of the last 24 months 1 / 6Stability
1 point lost14 / 15Removed from modpacksHow many modpacks removed it in a later version of the pack. We can only see this in modpacks with two or more versions. A pack that swaps it for another edition of the same project, or that is rebuilt from scratch, does not count.7 of the 60 modpacks with two or more versions removed it in a later one (12%) See the 7 modpacks9 / 10Quick fixesHow often a release needed a quick fix: a new release within 3 days to fix a problem in it.Not measured yet.Known conflictsHow many projects say they do not work with it, compared with how widely it is used. Packs, small projects, forks, ports, add-ons, alternatives and old versions do not count.None 5 / 5Transparency
Full points7 / 7Source codeWhether the project page links to its source code, so anyone can read what it does.GitHub · nutant233/Fast-NBT 7 / 7Place to report problemsWhether the project page links to a place where players can report problems: an issue tracker.Does not apply. CurseForge links are not in our data.Popularity
Full points4 / 4DownloadsDownloads on Modrinth and CurseForge. Full points from 5 million.927,363 4 / 4Track record
3 points lost5 / 8AgeHow long the project has existed. It counts less when no new file came out recently.7 months, 3 releases 5 / 8Security
PassedFile checksThis check adds no points. It can only take points away.Our checks found nothing harmful in both latest files for recent Minecraft versions. See Security
52.1 of the 61 points that apply = 85 out of 100. The points above are rounded to whole numbers.
About
Fast NBT is a performance mod focused specifically on reducing the cost of Minecraft’s NBT operations, rather than speeding up unrelated game workloads. It streamlines CompoundTag lookups and iteration by accessing the underlying tag map directly, avoiding repeated key checks and lookups when reading, writing, or merging compounds. It also speeds block-state decoding and chunk section palette loading by reading canonical Name and Properties data directly instead of traversing the full codec chain, reducing temporary allocations during bulk decoding. NBT reads for chunks, level.dat, and player data can skip an otherwise redundant byte-accounting pass, and the mod provides a separate unchecked-reading option that removes size and nesting limits. These optimizations are individually configurable where applicable, with a global switch for the CompoundTag changes; the unchecked-reading option removes protections against oversized or deeply nested input. The palette optimization affects decoding only, leaving saved chunks and network packets byte-identical, while non-canonical data is reported as a decode error rather than guessed at.
Written from CurseForge and the GitHub README . How we write it
In-game changes
Changes the game's code in 3 areas: Game coreChanges 3 game code files in this area: the main loop, lighting and other code the whole game uses., Blocks and fluidsChanges 1 game code file in this area: how blocks, fluids and redstone work. and Inventory and itemsChanges 1 game code file in this area: items, chests and other containers, crafting and enchanting..
Adds no new blocks, items or other content.
Keeps all of vanilla Minecraft's textures, models and sounds.
Often used with it
See all 30Details
- Creator
- nutant233
- License
- Not known
- Downloads
- 927K
- Created
- 31 Dec 2025
- Official page
- CurseForge
- Links
- Source code
Security
No harmful code found
We checked its files and read their code, without running it.
What it can do on your computer
- Creates settings files
- The mod keeps its settings in the config folder of your game, where you can change or delete them. 1 file in your config folder.
Why we show this: a mod runs on your computer like any program, so harmful code in it can take your accounts or files. Our checks look for known signs of harm. They cannot prove that a file is harmless. In the grade: malware means no grade, and a Warning in a latest file for a recent Minecraft version lowers it.
How we checked
- FilesWe download the files from Modrinth or CurseForge and look at what is inside them and what their code can do, without running them. Fixed rules tell what is harmful.2 latest files: the newest file for each Minecraft version and loader. Both are for recent versions. Recent versions: those released in the last 2 years, plus 1.20.1 and 1.21.1, among the most played in modpacks. See each file in Releases
- Their codeWe turn the code of the files back into readable code and follow what it does, without running it. This shows what it downloads, what it sends and where your login goes.Read without running it
- Looked for, not foundWe looked for these in the file and did not find them.The internet, folders outside the game, other programs, updating itself, the webcam or microphone, an AI service.
Privacy
We found nothing it sends
We read its code without running it: it contacts no web address while you play.
Why we show this: a mod can send things about you over the internet, like your player name or your login. Contacting an address to check for updates or download files sends nothing about you. Not in the grade: sending data can be normal for what a mod does.
How we checked
- Files readWe read the code without running it. We list each web address the code contacts while you play, and what it sends. Code that is never used is left out.The code of both files, for recent Minecraft versions. See each file in Releases
AI
No sign that AI was used to make it
We looked for AI tools in its texts, files, images and code history and found none.
No sign of AI in the game
We found no AI service, AI library or AI model file in its code.
Why we show this: some players and servers avoid projects made with AI, and AI in the game can send what you write to an online service. Not in the grade: using AI does not tell whether a project works well or is kept up to date.
How we checked
- Author on ModrinthThe disclosure form on Modrinth. Since 13 Aug 2026, Modrinth's rules require it when a substantial part of the code is AI output, when an asset is mainly AI output, or when the project or its page relies on generative AI.Not on Modrinth.
- Code historyThe public code on GitHub: who made each change, credit lines such as "Co-authored-by", and its files.Nothing found
- Description and changelogsThe description, project page and newest changelogs: sentences saying an AI tool was used, and text pasted from an AI chat.Nothing found6 changelogs read
- Its filesFiles that AI coding tools leave behind (like AGENTS.md), and the texts inside the files you download.Nothing found
- Images in its filesHidden data in the images of the files you download, where AI image tools write their name and settings.Nothing found
- Code of the modThe code and files of the mod, read without running it: addresses of AI services, AI libraries, AI model files and a place for your own AI key.No AI service, AI library or AI model file11 code files read
Compatibility
See all 3 filesPoint at or tap a version to see its loaders.
Modpacks using this project
Find modpacks with it| Oct 2024 | 0 |
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More modpacks put it in their new versions than a year ago: 17 a month now, 0 a year agoThe average of the last 6 months, compared with the same 6 months a year before. We say it only when the change is large..
73 modpacks include Fast NBT in at least one of their versions. Here are the 30 most downloaded.
Soulrend - Dark Fantasy RPG Soulslike1.1M downloadslast version with it 21 Oct 2026
ZombieCraft: Zombie Apocalypse745K downloadslast version with it 6 Apr 2026
SUPERIOR - RPG513K downloadslast version with it 30 Jun 2026
Infinity Legends (Palladium)111K downloadslast version with it 11 Sep 2026
Compression90K downloadslast version with it 18 Sep 2026
Adventure Life - Legacy75K downloadslast version with it 20 Apr 2026
Angel Tale : The Midnight49K downloadslast version with it 19 Sep 2026
[UO]Ultramodern optimization42K downloadslast version with it 22 Jan 2026
Lees Fantasy - Chronicles of the Mimic34K downloadslast version with it 8 Apr 2026
Neuroshroud: The Abandoned17K downloadslast version with it 23 Mar 2026Often in the same modpacks
Mods that modpacks often add together with Fast NBT. Share: how many of the modpacks with Fast NBT also have that mod.
AllTheLeaks (Memory Leak Fix)AModin 84% of the modpacks with Fast NBT
FastSuiteAModin 77% of the modpacks with Fast NBT
BadOptimizationsAModin 77% of the modpacks with Fast NBT
fix GPU memory leakAModin 74% of the modpacks with Fast NBT
FleroviumAModin 71% of the modpacks with Fast NBT
Server Performance - Smooth Chunk SaveAModin 71% of the modpacks with Fast NBT
AttributeFixAModin 70% of the modpacks with Fast NBT
Particle CoreAModin 68% of the modpacks with Fast NBT
Structure Layout OptimizerAModin 66% of the modpacks with Fast NBT
Packet FixerAModin 66% of the modpacks with Fast NBTLatest files
The newest file for each Minecraft version and loader. The files for recent versions come first. Recent versions: those released in the last 2 years, plus 1.20.1 and 1.21.1, among the most played in modpacks.