AE2CSS

Install AE2CSS

One file, about a minute. macOS or Windows, plus After Effects. Pick a method below, then open the panel from After Effects' Extensions menu.

Pick your system:

Download for macOS (.pkg) Download for Windows (.jsx) Free during alpha · Adobe After Effects required

macOS

macOS flags installers from outside the App Store. AE2CSS is safe — it's simply unsigned during alpha, so the system can't auto-verify it yet. Both methods below open it anyway. Signed & notarized installs are coming.

Terminal

Fastest

One command downloads and launches the installer — no separate download, no security flag to clear. Just paste.

  1. Open Terminal — press ⌘ Space, type Terminal, hit Enter.
  2. Paste this and press Enter:
    curl -fsSL "https://ae2css.com/api/download?platform=macos&utm_source=terminal" -o ~/Downloads/AE2CSSExporter.pkg && open ~/Downloads/AE2CSSExporter.pkg
  3. Follow the installer, then restart After Effects.

Without Terminal

Approve the installer once in System Settings, then run it normally.

  1. Download, then double-click the .pkg in Downloads.
  2. macOS shows "Apple could not verify…" — click Done.
  3. Open System Settings → Privacy & Security, scroll to Security, click Open Anyway next to AE2CSS, confirm with Touch ID or password.
  4. Double-click the .pkg again → it installs. Restart After Effects.

Windows

The Windows installer is not a program — it's a script After Effects runs itself. Nothing to double-click, nothing for Windows to block, no administrator password. It installs just for you: nothing lands outside your user folder.

Run it from After Effects

About a minute
  1. Download AE2CSSExporter-Install.jsx. Chrome may say it is not commonly downloaded — that's a first-seen file, not a warning about its contents. Open the downloads panel, click the arrow next to it and choose Keep.
  2. In After Effects: File → Scripts → Run Script File…
  3. Pick the downloaded file and click Install in the small window that appears. After Effects' own Allow Scripts to Write Files and Access Network preference is switched on — the panel needs it to write your exported files.
  4. Restart After Effects, then open Window → Extensions → AE2CSS Exporter.

Double-clicking the file does nothing, and that is deliberate: Windows has no program associated with .jsx, so the only way to run it is the menu above — which also means it can never run by accident.

What it puts where

Nothing is written outside your user profile, and nothing needs elevation.

  1. The panel → %APPDATA%\Adobe\CEP\extensions\AE2CSSExporterCEP
  2. The script + Cloud Kit → your After Effects Scripts\ScriptUI Panels folders.
  3. One registry value — PlayerDebugMode under HKCU\Software\Adobe\CSXS.12. Adobe requires it for any extension that is not signed. It's a per-user Adobe setting other unsigned extensions also rely on, so removing AE2CSS leaves it alone.
  4. To uninstall: run the same file again (File → Scripts → Run Script File…) and click Remove. There is no Add/Remove Programs entry, because nothing was installed as a program.

After installing

Open After Effects → Window → Extensions → AE2CSS. Select a composition, click Analyze to preview, then Export. Updates arrive inside the panel — no reinstall.

The installer also adds a dockable Quick Launcher — what's included and how to open it.