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Jul 14, 2026
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The latest articles and tutorials from the Upsun Developer Center.
How It WorksJul 14, 2026
Can you trust the X-Client-IP header?
Why the X-Client-IP header on Upsun holds the real visitor IP behind Fastly, Cloudflare, and CloudFront, and how to log real client IPs behind any other CDN.
How It WorksJul 7, 2026
Write a Git server with per-branch permissions in five minutes
Upsun’s most basic API is a Git server. Build one in Python with Dulwich and Paramiko, and add per-branch read permissions in a single method.