[techbio]

Author appears to use "downstream" and "upstream" to refer to "further down the stack" and "further up the stack".

Is this normal usage? Seems reversed to me.

[astine]

It seems backwards to me too. I usually see these terms when referencing dependencies in software projects, ie: Ubuntu is downstream from the Linux kernel. I would think that you would see the same thing with services.

[dmichulke]

It depends on whether you look at control flow (who calls whom) or data flow.

[jholman]

This is the issue, yeah.

To rephrase that, "upstream" means "where events come from".

[clarkmoody]

Seems reversed to me too. Literally, "upstream" is water coming from uphill, flowing to you, and then going "downstream" to some other destination.

If the river is data, then stuff you depend on is upstream from you, and things that depend on you are downstream.

[ThrustVectoring]

Feels right to me, though I'm no authority figure on this matter. The visual I get is that requests flow from the end-user your service is supporting down to things that indirectly support your user.