Confirmed: jsonc wins, and Wrangler says nothing
To find the actual precedence rule instead of guessing from the docs, this was tested directly against wrangler@4.119.0 in an isolated project: a valid wrangler.toml alongside a wrangler.jsonc whose main field pointed at a file that doesn’t exist.
name = "test-worker"
main = "index.js"
compatibility_date = "2026-08-01"{
"name": "test-worker-jsonc",
"main": "does-not-exist.js",
"compatibility_date": "2026-08-01",
}✘ [ERROR] The entry-point file at "does-not-exist.js" was not found.
This might mean that your entry-point file needs to be generated (which is
the general case when a framework is being used). If that's the case
please run your project's build command and try again.The error came from the jsonc file’s broken main path, not the toml file’s valid one. That confirms the precedence: wrangler.jsonc wins whenever both files exist, and Wrangler never mentions the toml file is being ignored. A team that starts migrating by copying settings into a new wrangler.jsonc, then keeps editing the old wrangler.toml out of habit, gets no signal at all that their edits stopped mattering the moment the new file appeared.
Why this keeps happening
Cloudflare’s own docs recommend wrangler.jsonc for new projects and note that some newer Wrangler features are JSON-config-only, but there’s no enforced migration path. cloudflare/workers-sdk issue #14501, opened 2026-07-01, asks for exactly the tooling that’s missing:
A proposal for a
wrangler config migratesubcommand that would rewritewrangler.tomltowrangler.jsoncin place while preserving comments where jsonc allows.
Until that ships, there’s no built-in safety net for the conversion. This site’s own deploy config is still on wrangler.toml, which makes the migration path a real, not hypothetical, question here too.
Check for both files before debugging anything else
If a Wrangler command is behaving differently than the wrangler.toml in
front of you suggests it should, check for a wrangler.jsonc or
wrangler.json sitting in the same directory first. It is the config actually
being read, and grepping the toml file for the setting in question will not
explain the behavior.
Structural Comparison Matrix
| Operational Aspect | Only wrangler.toml present | Both files present |
|---|---|---|
| File Wrangler reads | wrangler.toml | wrangler.jsonc, silently |
| Warning printed about the other file | N/A | None, confirmed by direct test |
| Official conversion tooling | N/A | Not yet shipped; issue #14501 is still open |
Fix it: migrate deliberately, then delete the old file
Manual conversion (no official tool yet)
# 1. Read the existing wrangler.toml values
cat wrangler.toml
# 2. Write the equivalent wrangler.jsonc by hand,
# matching every field (bindings, routes, vars, compatibility_date)
$EDITOR wrangler.jsonc
# 3. Confirm the new file alone produces the expected deploy
wrangler deploy --dry-run
# 4. Only once step 3 looks right, remove the old file
rm wrangler.tomlDon’t keep both files around “just in case.” Since Wrangler reads the JSONC file exclusively once it exists, the TOML file becomes dead weight the instant the new one is created, not a fallback. Anyone editing it later is editing a file nothing reads.
Confirmed version
Reproduced directly against wrangler@4.119.0. The precedence and silent-ignore behavior aren’t new in that specific release; they reflect how Wrangler has resolved config files for some time. What’s newer and dated is the open request for tooling to close the gap: issue #14501, 2026-07-01. Browse more posts like this in the Dev Tools archive.
