MSDL
Get official Windows ISOs directly from Microsoft's CDN — no account, no MCT.
1000s → ~75
MS calls/day
4
Cache layers
5
Install channels
38
Languages
01 / The problem
Microsoft gates real ISOs behind an account and the Windows-only Media Creation Tool — no path for Linux, macOS, or IT admins scripting rollouts.
02 / The approach
Reverse-engineered the same session-registration flow Rufus's Fido.ps1 uses, and rebuilt it as a stateless Go proxy any platform can call directly.
03 / The catch
At real traffic, Microsoft throws error 715-123130 and blocks the calling IP. The whole caching architecture exists to survive scale without ever hammering their servers.
Open-source tool for downloading official Windows ISO files directly from Microsoft's CDN, bypassing the Media Creation Tool entirely. Supports 38 languages and ARM64/x64/x86 architectures. Frontend in React 19 + TypeScript + Tailwind v4, backend in Go 1.22 using stdlib net/http with RWMutex-cached session parsing. Deployed on a VPS via direct HTTP.
Highlights
4-layer cache (SKUs, signed links, eval redirects, negative results) with jittered TTLs
singleflight collapses 500 concurrent cache misses into a single outbound Microsoft call
CLI contributes fetches back to warm the same cache the website reads from
Ships as web app + CLI across winget, Homebrew, a curl installer, raw binaries, and Termux/Android
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