Edit in your browser

There is nothing to install. Open the editor, point it at your save folder, and edit exactly as you would in the desktop app.

Your saves never leave your computer. There is no server: the editor is a program that runs inside the page, and it reads the folder you choose directly off your disk. Nothing is uploaded anywhere.

Which folder to choose

This is the one thing worth getting right, because picking the wrong level costs you features.

Choose the folder for the account, not one world:

SaveGames/
└── 76561198000000000/     <- choose THIS one
    ├── ScientistCustomization_1.sav
    └── Worlds/
        ├── Cascade/
        └── Chrissie/

You can open a single world folder (Cascade above) and everything inside it works. But your character's look is stored next to Worlds/, not inside it, so a browser given only one world cannot see it. Open the account folder and every world is listed together, with the appearance editor working too.

Finding it on your computer

On Windows, saves live under %LOCALAPPDATA%\AbioticFactor\Saved\SaveGames\<your SteamID>. Paste that into the address bar of the folder chooser.

Press OPEN FOLDER, choose that folder, and allow the browser to view it when it asks.

You can also drag the folder onto the page instead of using the chooser - anywhere on the window will do.

Coming back later

The editor remembers the last three worlds you opened and offers them on its home page, so a refresh does not mean hunting through the folder chooser again. Press OPEN on one and your browser will ask permission to read that folder once more (it deliberately forgets that permission when you close the tab). If a world has been moved or deleted since, the editor says so and you can remove it from the list.

Nothing about your save is stored: what is remembered is a bookmark to the folder, not its contents.

Opening a zip

OPEN A ZIP on the home page takes a zipped save folder - either the one EXPORT gave you, or one you made yourself by zipping the world folder. You can drop a .zip onto the page too.

This is the way back in for Firefox and Safari, where the editor cannot reopen a folder: export your zip before you close the tab, then drop it back on next time and carry on. Saves opened from a zip are edited in the tab and leave the same way, through EXPORT.

Your browser matters

Browser	What happens
Chrome, Edge, Opera	Full use. The editor writes changes straight back to your save folder, keeping a .bak of the old file each time, exactly like the desktop app.
Firefox, Safari	Read-only. The editor can open your folder and edit everything, but the browser will not let any web page write to your disk. Your changes live in the tab until you export them.

On Firefox and Safari, nothing is lost as long as you export before closing the tab. The editor says so on screen rather than letting you find out afterwards, and the browser itself will ask you to confirm before you close or reload a tab holding unsaved edits.

Getting your saves back out

EXPORT, above the save list, downloads every file in the world as one zip, laid out the same way the game's folder is, so you can copy it straight back over your save folder.

Take the whole set rather than one file wherever you can: editing one save can quietly change others. Setting a story chapter, for example, rewrites the world save and can rewrite every player save with it.

If you are certain you only want one file, right-click any save in the list and choose EXPORT THIS SAVE. That gives you just that .sav.

Export saves what is on disk

Press SAVE first. An edit still open in the editor is not in the export.

What the browser cannot do

A web page is not allowed to roam your computer, so a few things are hidden in the browser and show a "needs the desktop editor" note instead. Everything else is the same editor.

Not in the browser	Why
Compare two saves	Picks two saves from anywhere on your machine.
Create a new world	Writes a whole folder of new files.
Settings files (.ini)	Found by searching folders on your computer.
Achievements	Needs the Steam files installed on your computer.
Finding your saves automatically	The editor cannot look around your disk; you point it at the folder.
Plugins	Load code, which a page cannot do.

Everything else - players, inventory, skills, recipes, the codex, worlds, containers, quest flags, pets, vehicles, story progression, your character's look, raw JSON import and export - works the same as the desktop app.

If you would rather install it

The desktop app has no such limits, reads your game's own item icons and names from your installed copy, and finds your saves for you. Download it here.