Wrangler "Unexpected field" / processing wrangler.toml failed in CI

By Kaveh Alemi·Latchkey

Wrangler validates wrangler.toml and rejected a key it does not recognize or one placed in the wrong section. A typo, a deprecated field, or a binding under the wrong table triggers "Processing wrangler.toml configuration" errors before anything deploys.

What this error means

Deploy fails with "Processing wrangler.toml configuration: - Unexpected fields found in ... : \"X\"" and lists the offending keys.

✘ [ERROR] Processing wrangler.toml configuration:
  - Unexpected fields found in top-level field: "buld"
  - Unexpected fields found in top-level field: "route"

Common causes

A misspelled or deprecated key

A typo like buld for build, or a key removed in a newer Wrangler, is not recognized and fails validation.

A field in the wrong table

Putting a binding or a per-environment key at the top level (or vice versa) makes Wrangler flag it as unexpected.

How to fix it

Correct the field name and placement

1. Read which field Wrangler flags and in which section.
2. Fix the spelling or move it to the correct table.
3. Check the field against the current Wrangler config reference.

name = "app"
main = "src/index.ts"
compatibility_date = "2024-09-23"

[build]
command = "npm run build"

Validate config before deploy

A dry-run surfaces config errors without pushing anything.

npx wrangler deploy --dry-run

How to prevent it

• Check keys against the current Wrangler configuration reference.
• Keep bindings and env keys in their correct tables.
• Run wrangler deploy --dry-run in CI before the real deploy.

Frequently asked questions

Related guides

References

• Terraform documentation
• GitHub Actions documentation