Workers: Route-level control for Worker script invocation on SPAs

For those building Single Page Applications (SPAs) on Workers, you can now explicitly define which routes invoke your Worker script in Wrangler configuration. The run_worker_first config option has now been expanded to accept an array of route patterns, allowing you to more granularly specify when your Worker script runs.

Configuration example:

{
	"name": "my-spa-worker",
	// Set this to today's date
	"compatibility_date": "2026-07-24",
	"main": "./src/index.ts",
	"assets": {
		"directory": "./dist/",
		"not_found_handling": "single-page-application",
		"binding": "ASSETS",
		"run_worker_first": ["/api/*", "!/api/docs/*"]
	}
}

name = "my-spa-worker"
# Set this to today's date
compatibility_date = "2026-07-24"
main = "./src/index.ts"

[assets]
directory = "./dist/"
not_found_handling = "single-page-application"
binding = "ASSETS"
run_worker_first = [ "/api/*", "!/api/docs/*" ]

This new routing control was done in partnership with our community and customers who provided great feedback on our public proposal ↗. Thank you to everyone who brought forward use-cases and feedback on the design!

Prerequisites

To use advanced routing control with run_worker_first, you'll need:

• Wrangler v4.20.0 and above
• Cloudflare Vite plugin v1.7.0 and above