Isolate
Boots your pack repeatedly in a sandbox, halving the mod list each time, until it has the smallest set that still reproduces the crash.
Modpack testing and optimization · Minecraft Java Edition
Stop guessing which mod
broke your server.
ModTamer boots your pack for real in an isolated copy, bisects the mod that breaks it, installs what it can prove, and verifies the fix by booting again. Your original server is never modified while it works — only when you decide to apply the fix.
What it does
Reading a log tells you what already broke.
ModTamer finds out why.
Repair
Resolves the dependencies it can prove from metadata, and says plainly which problems still need a human. It never guesses a mod by searching for its name.
Benchmark
Measures TPS, tick time and per-mod cost under a documented load, so "it lags" turns into a number you can act on.
Validate
Talks to the running server's console and asks whether each mod actually registered its content — catching the ones that load and then silently do nothing.
Update
Tests newer versions in a copy and boots them before you apply anything to the server people are playing on.
Migrate
Tells you exactly what you would lose moving to a new Minecraft version, before you spend a weekend finding out.
The part nobody else does
It does not read the log.
It reproduces the crash.
When the log is not enough, ModTamer boots your pack over and over in a sandbox, halving the mod list each time, until only the culprit is left. Below: a real run, start to finish.
How it works
Three steps. The work happens on a copy.
-
1
Point it at your server folder
Drag it onto the window. ModTamer reads every jar, builds the dependency graph and lists what is wrong — in seconds, without launching anything.
-
2
It works on a copy
Every experiment runs on an isolated snapshot with its own Java and its own world. Your original folder is never modified. That is not a setting; it is how it is built.
-
3
You decide what gets applied
Nothing reaches your real server unless you say so. When it does, a backup is taken first, and only jars inside
mods/are written — never your world or your configuration.
Free, right now
Paste a crash log.
No account, no install. It tells you what failed and which mods are involved.
Analysed in memory and discarded. Paths containing your username are stripped
before anything is shown back.
By using it you accept the terms and the
privacy policy.
Plans
Not on sale yet.
These are the prices. You cannot buy yet — accounts and licences are still being built, and selling something we cannot hand over would be a strange way to start. Tell us where to write and you will know the day it opens.
Free
Free
No card, no account
- Static analysis of any pack — no size limit, ever
- The dependency graph and every finding
- One complete test run, whatever size your pack is
- The log analyser on this page
Standard
US$7.99
per month · or US$79.90 a year
- Everything in Free
- Unlimited isolation, repair and validation runs
- Boots packs up to 200 mods
- Two computers
- Performance benchmarking
Pro
US$17.99
per month · or US$179.90 a year
- Everything in Standard
- No artificial mod limit — your hardware is the limit
- Five computers
- Version migration planning
- Live server monitoring
Reading the ladder: analysis is never capped, on any plan. Your first complete test run is free whatever the size of your pack, because a limit by size would shut out exactly the people with the real problem — and since everything runs on your own machine, that run costs us nothing. What a plan buys is doing it again, as often as you need.
Never "unlimited mods": in Pro the ceiling is set by Minecraft, the loader and your hardware, and that is how we say it. Prices are in US dollars; taxes are calculated at checkout by Paddle, who will be the seller of record.
Verified
What we actually test.
These are the combinations ModTamer boots and checks automatically, not a list we typed. Outside them it may work, but nobody verified it — so we do not claim it.
- forge · Minecraft 1.20.1
- neoforge · Minecraft 1.21.1
Launch
Get told when it ships.
One message, when it launches. That is the whole plan.