project-slim.nsi

Online bootstrapper — small download.

6 minmedium

The slim installer (project-slim.nsi) is ~22 MB. It uses the WebView2 online bootstrapper — a 1.8 MB exe that downloads the full runtime from Microsoft at install time. Right choice when bandwidth at install time matters.

When slim wins

Email distribution — most providers cap attachments at 25 MB
Web downloads where the conversion drops with file size (every extra MB hurts)
Users on metered cellular at install — they'd rather download 22 MB once and let WebView2 install over Wi-Fi later
GitHub release size limits (2 GB per asset is generous, but for older repos, smaller assets fit better)

The shape — minus the WebView2 bundle

build/windows/installer/project-slim.nsi (excerpt)

# Same Welcome/Directory/Install/Finish flow
!insertmacro MUI_PAGE_WELCOME
!insertmacro MUI_PAGE_DIRECTORY
!insertmacro MUI_PAGE_INSTFILES
!insertmacro MUI_PAGE_FINISH

# Wails' default bootstrapper macro — downloads WebView2 at install
!insertmacro wails.webview2runtime

Section
    !insertmacro wails.setShellContext
    !insertmacro wails.files                   # main binary
    !insertmacro wails.writeUninstaller
SectionEnd

wails.webview2runtime drops a 1.8 MBMicrosoftEdgeWebview2Setup.exe bootstrapper. At install time, it runs that bootstrapper which contacts Microsoft and downloads the ~125 MB runtime if not present.

What happens on the customer's machine

Customer downloads the 22 MB slim installer.
Runs it. NSIS prompts: Welcome → Directory → click Install.
NSIS extracts the main binary + bootstrapper.
Bootstrapper checks if WebView2 is installed. If yes, skip. If no, download from Microsoft (needs internet).
Total install time: 30s if WebView2 already there; 2-3 min on a slow connection if not.

Customer with no internet at install time runs the slim installer. The bootstrapper fails. The user sees a WebView2 install error mid-wizard. They're confused. Ship the full installer in that case.

When to ship full vs slim

Channel	Use
Web download from your site	Slim — convert better; users typically online
Email attachment	Slim — fits in < 25 MB caps
USB stick / on-prem install	Full — assume no internet
Air-gapped customer	Full
In-app auto-update	Neither — uses the raw .exe (chapter 4)

Ship both, let the customer pick

Grit's release script publishes both as GitHub release assets. Your download page can offer both with a brief description of when to use each. Most customers pick slim; the full is there for the edge case.

Your download page

Download FieldPOS

Recommended:
[ Download FieldPOS-Setup-Slim-v1.2.3.exe ]  22 MB

Don't have internet during install?
[ Download FieldPOS-Setup-v1.2.3.exe (full) ]  150 MB

Quick check

A customer-success ticket: 'Installer hangs at 60%.' Customer is on a satellite internet connection in a remote area. They downloaded the slim installer. What's most likely happening?

Try it

Compare the two installers side-by-side:

Build both via your release script
List the file sizes: FieldPOS-Setup-v0.1.0.exe + FieldPOS-Setup-Slim-v0.1.0.exe
Install the slim version on a connected PC. Time how long it takes from double-click to first launch.
Uninstall.
Repeat with the full version on a disconnected PC.

Paste your numbers in notes.md.

What's next

Last lesson — the branded MUI bitmaps. Make the installer look like YOUR product, not a default NSIS template.

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