Serve the app under a path

Use this guide to move the app from its workers.dev URL to your own hostname. Either the Worker gets a whole hostname (https://receipts.example.com/), or it shares a hostname with other content and answers only under a path (https://example.com/app/). The second case needs APP_BASE_PATH.

Prerequisites

A domain on Cloudflare DNS in the same account as the Worker.
The config file you deploy with (wrangler.production.jsonc if you used bun run setup, or wrangler.jsonc in your repository copy if you used the Deploy button). Routes and APP_BASE_PATH cannot be changed in the app.
If you use OneDrive upload or Cloudflare Access, be ready to update them afterwards (see the end of this page).

Give the app a whole hostname

Add a custom domain to the config
wrangler.production.jsoncjsonc
```
"routes": [
  { "pattern": "receipts.example.com", "custom_domain": true }
]
```
The hostname must not already have a CNAME record. Cloudflare creates the DNS record and certificate for you.
Deploy
```
bun run deploy
```
With the Deploy button, commit and push the change instead. You can also add the domain in the dashboard under your Worker’s Settings > Domains & Routes > Add > Custom domain, but a later deploy replaces dashboard routes with the ones in your config, so keep the config as the source of truth.

Leave APP_BASE_PATH empty in this case.

Set the base path
Add APP_BASE_PATH to vars. It must start with /, for example /app, and may use letters, digits, ., _ and -. A trailing slash is removed.
wrangler.production.jsoncjsonc
```
"APP_BASE_PATH": "/app"
```
Add two routes
Add a route for the path itself and one for everything under it:
wrangler.production.jsoncjsonc
```
"routes": [
  { "pattern": "example.com/app", "zone_name": "example.com" },
  { "pattern": "example.com/app/*", "zone_name": "example.com" }
]
```
The hostname needs a proxied DNS record or another Worker on it already (for example your website). Routes take precedence over a custom domain on the same hostname, so the rest of the site keeps working.
Deploy
Run bun run deploy, or commit and push with the Deploy button.

With a base path, the app prefixes every link, form, redirect and export link with it, and answers HTTP 404 to any path outside it. This also applies on the workers.dev URL, so the app is then at https://<worker>.<subdomain>.workers.dev/app/.

Check it worked

Open https://example.com/app/ (or your custom domain). The app asks you to sign in and then shows Home.
Click through to Settings. The address bar keeps the /app prefix.
In Settings > Advanced > Set when deployed, Address shows your base path, or “Site root” without one.
Open a path on the same hostname outside the base path. It is served by your other content, not by the app.

If every page answers 404, APP_BASE_PATH and the routes do not match. Fix one of them and deploy again.

Update what depends on the address

Cloudflare Access: protect the new hostname. With a base path, add the hostname with the paths app and app/*. See Protect the app with Cloudflare Access.
OneDrive upload: add the new redirect URI to your Microsoft Entra app. Settings > Sending > OneDrive > Redirect URI for Microsoft Entra shows it. See Upload the month to OneDrive.
Your bookmarks: the old workers.dev address keeps working unless you set "workers_dev": false.

Configuration for APP_BASE_PATH.
App pages lists every path, relative to the base path.
Cloudflare’s Custom Domains and Routes.