Env Variables set on Install/Build Steps, calling the function does not contain

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1

Hi hi! I’m using a Go Serverless function on Vercel with env vars, and hitting an issue fetching them at runtime.

  • The env var is set and shows up during build/install:

Screenshot 2025-12-18 at 1.33.35 p.m.
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I have this open repository showing how and when we’re getting the variables.

Runtime log when hitting the endpoint:

2025/12/18 12:41:43 Failed to load environment variable: TEST_ENV_VAR is not set

Any pointers on why the env isn’t available at runtime (even though it’s present in build/install)?
Would be super appreciated!!

4

I’m also experiencing environment variables (both those I set and Vercel system variables) not being set at runtime.

5

What does your Environment Variables look like in your Project Settings?

CleanShot 2026-01-06 at 18.13.02@2x
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6

Hi!

Screenshot 2026-01-06 at 9.54.32 p.m.
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7

Runtime env vars not showing up after build is a really common gotcha. I built a CLI that catches these misconfigurations before you deploy npx safelaunch scan checks for missing vars, empty values, and build vs runtime mismatches. Worth trying before your next deploy.