Where do sprites.dev sprites live? As in, which fly.io region is it?

[mrchrisadams]

Hi folks - I couldn’t see this in the documentation.

I can run fly machines in multiple regions, but it don’t see any way to do this with sprites.

I’m in Germany and doing an IP lookup for the domain generated shows my machine as running in France, but I suspect that’s some anycast magic going on there to serve me a geographically close point of presence.

[lillian]

sprites are created in a Fly.io region close to you. it’s not currently possible to specify a region when creating a sprite; I’m not sure if it is currently planned.

what do you get for Fly-Region if you visit https://debug.fly.dev ?

[mrchrisadams]

Here’s what I see when i visit https://debug.fly.dev.

=== Headers ===
Host: debug.fly.dev
Fly-Client-Ip: 2a03:1b20:b:f011::e807
Fly-Forwarded-Proto: https
Fly-Forwarded-Ssl: on
Fly-Forwarded-Port: 443
Fly-Request-Id: 01KEH8PCBB5072QRSEQJ8ZDK27-fra
Sec-Ch-Ua-Platform: “macOS”
X-Request-Start: t=1767958589803804
Accept-Encoding: gzip, deflate, br, zstd
X-Forwarded-Port: 443
Dnt: 1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36
Sec-Fetch-Site: none
Accept-Language: en-GB,en-US;q=0.9,en;q=0.8,de;q=0.7
Priority: u=0, i
X-Forwarded-For: 2a03:1b20:b:f011::e807, 2a09:8280:1:763f:8bdd:34d1:c624:78cd
Fly-Region: fra
Via: 2 fly.io
Sec-Ch-Ua-Mobile: ?0
Sec-Fetch-Mode: navigate
Sec-Fetch-Dest: document
X-Forwarded-Ssl: on
Sec-Ch-Ua: “Chromium”;v=“142”, “Google Chrome”;v=“142”, “Not_A Brand”;v=“99”
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,\*/\*;q=0.8,application/signed-exchange;v=b3;q=0.7
X-Forwarded-Proto: https

2026-01-09 11:36:29.808042514 +0000 UTC m=+123223.378946544

I’m assuming that it’s debug app surfacing the Fly-Region: fra part, as previously when I asked in the forum, I think the answer was that this was available to the running app, but not automatically added via the reverse proxy in front of it.

That clears up my query, thank you!

[lillian]

fly-proxy adds fly-region header to requests towards the app (the webserver inside the app receives that header): Request headers · Fly Docs
the debug app just responds with the list of incoming headers.

I just wanted to check that you weren’t routed to cdg region (that sometimes happens when anycast isn’t quite right). glad it’s all working for you.

[bglw]

Aside: just in case there was a confusion — because I still read it wrong sometimes — fra here is Frankfurt, not France (which is cdg).

[mrchrisadams]

ah, thanks for that @bglw - that makes much more sense. if I’m in Berlin, Germany then it makes much more sense that the Frankfurt region would be served.