Cloudflare Workers

Target name: workerd. This is the default target.

npx edgefit check --target workerd

Wrangler integration

If the project root has a wrangler.jsonc, wrangler.json or wrangler.toml, edgefit reads:

• main as the entry point, when no --entry or config entry is given. It is read relative to the config it is written in
• compatibility_date
• compatibility_flags

A build can leave a deploy config for wrangler to use instead: .wrangler/deploy/config.json points to it. Nitro 3 does this and writes no config in the project root. edgefit follows the redirect first, like wrangler, so a Nitro build needs no --entry and its compatibility date and flags are read from .output/server/wrangler.json.

The report header shows where the settings came from:

settings compatibility_date 2026-09-29, flags: nodejs_compat (from wrangler.jsonc)

Without a wrangler config, edgefit uses the settings the compatibility data was generated with (its date and nodejs_compat), and says so in a note in the report and in the JSON notes. A wrangler config that has no compatibility_flags enables none, as on Workers. One with no compatibility_date gets the data's date, with a note. You can override any of this in the config file.

Compatibility date and flags

Workers turns on native Node modules one by one, gated by compatibility flags that become defaults at a given date when nodejs_compat is on. For example, fs is native from 2025-09-15 with enable_nodejs_fs_module, and child_process from 2026-03-17.

A module that is not native at your date and flags is reported as mocked, because wrangler bundles an unenv polyfill in its place. Moving your compatibility date forward often clears a group of findings at once.

What the data covers

• Node API data from workers-nodejs-compat-matrix, generated with workerd 1.20260929.1.
• Curated overrides for APIs that the matrix reports as present but that throw or do nothing when called. Some examples:

API	Result	Why
node:fs.watch	unsupported	throws ERR_UNSUPPORTED_OPERATION
node:child_process.*	unsupported	throws ERR_METHOD_NOT_IMPLEMENTED; Workers cannot spawn processes
node:dgram	mocked	sockets accept calls but never send or receive
node:readline	mocked	functions are no-ops; interfaces never emit input

The full list is in data/overrides/workerd.json in the package. Each entry links to the workerd source file it was read from.

Export conditions

Packages are resolved with workerd, worker and browser, then import, require and default. A package with a Workers-specific build is checked on that build.