INCIDENT RUNBOOK

Fix: Env Variable Undefined At Build in Hono on Render

Comprehensive architectural post-mortem and verified configuration patch for hono deployed in render production environments.

Automated Remediation ProtocolUpdated for 2026 Production

Facing env-variable-undefined-at-build in CI/CD or runtime containers?

Review the verified configuration patches below. To automate incident triage and fine-tune your own internal agents, check out our production AI training datasets.

🧠 Explore Security & Code Datasets →All Runtime Fixes →

● Observed Terminal Error / Stack Trace

Error: Cannot read property 'VARIABLE_NAME' of undefined
    at Object.<anonymous> (/app/index.js:5:26)
    at Module._compile (internal/modules/cjs/loader.js:1085:14)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1114:10)
    at Module.load (internal/modules/cjs/loader.js:950:32)
    at Function.Module._load (internal/modules/cjs/loader.js:790:12)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:75:12)

Root Cause Analysis

The error occurs due to a mismatch in the lifecycle of environment variable injection during the build process on Render. Specifically, Hono's build process attempts to access environment variables before they are fully initialized by Render's platform, resulting in an undefined state. This incompatibility arises from the differing expectations of environment variable availability between Hono's build process and Render's deployment lifecycle.

● Configuration & Code Resolution

To fix this issue, update your `render.yaml` file to include a `build` command that sets the required environment variables before running the build process for Hono. Specifically, modify the `build` section to include environment variables like so:
yaml
diff --git a/render.yaml b/render.yaml
--- a/render.yaml
+++ b/render.yaml
@@ -5,6 +5,10 @@
   build:
     command: |
       export VARIABLE_NAME='value'
+      export ANOTHER_VARIABLE='another_value'
       hono build
``

Verification & Build Command

render preview --service my-hono-service && curl https://my-hono-service.onrender.com