--- description: Serve Preview URLs from custom domains and protect them with Cloudflare Access. title: Custom domains image: https://developers.cloudflare.com/workers/previews/custom-domains/og.png?v=9983358f175f5b1c --- [Skip to content](#main-content) > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/workers/llms.txt > Use this file to discover all available pages before exploring further. # Custom domains Last updated Sep 24, 2026|Copy as Markdown| [View as Markdown](https://developers.cloudflare.com/workers/previews/custom-domains/index.md)| [Agent setup](https://developers.cloudflare.com/agent-setup/) Preview URLs can use a custom domain, `workers.dev`, or both. Enable at least one host to get a Preview URL. | Host | Preview URL | Unique deployment URL | | --- | --- | --- | | Custom domain | `.app.example.com` | `-.app.example.com` | | `workers.dev` | `-..workers.dev` | `-..workers.dev` | ## Before you start Configure Previews in the same system that manages your custom domain: | Managed with | Configuration | | --- | --- | | Wrangler | Use the **Wrangler** tab, then run `npx wrangler deploy`. | | Dashboard | Use the **Dashboard** tab. | | Terraform | Update and apply your Terraform configuration. | ## Enable custom domain Preview URLs The following example configures `app.example.com` for Preview traffic only. Add `previews_enabled` and set `enabled` to `false`, then run `npx wrangler deploy` to apply the configuration. ```jsonc { "routes": [ { "pattern": "app.example.com", "custom_domain": true, "previews_enabled": true, "enabled": false } ] } ``` ```toml [[routes]] pattern = "app.example.com" custom_domain = true previews_enabled = true enabled = false ``` Choose which traffic the custom domain serves: | Traffic | `previews_enabled` | `enabled` | | --- | --- | --- | | Preview only | `true` | `false` | | Production and Preview | `true` | Omit or set `true` | 1. In the Cloudflare dashboard, go to **Workers & Pages** and select your Worker. [Go to **Workers & Pages** ↗](https://dash.cloudflare.com/?to=/:account/workers-and-pages) 2. On the **Domains** tab, under **Custom Domains and Routes**, select **+ Add Domain**. 3. Enter your domain. For **Enable for**, select *Preview* or *Production and Preview*. Then select **Add domain**.![Add Domain modal with Enable for set to Preview](https://developers.cloudflare.com/cdn-cgi/image/onerror=redirect,width=1040,height=756,format=webp/_astro/replace.D64Ztqrs.png) 4. Confirm that the domain appears under **Custom Domains and Routes**.![Domains tab showing a custom domain enabled for Preview traffic](https://developers.cloudflare.com/cdn-cgi/image/onerror=redirect,width=2876,height=1454,format=webp/_astro/customdomainonly.8AG_6tc-.png)
DNS and certificate behavior Cloudflare creates a wildcard DNS record and SSL certificate for the custom domain, such as *.app.example.com. Certificate issuance can take time after you create the first Preview. Use a dedicated hostname such as previews.example.com if your production domain already has subdomains. This avoids wildcard conflicts. Preview URLs add another subdomain to your hostname. For example, app.preview.example.com creates <preview-name>.app.preview.example.com. For deeper hostnames, you may need Advanced Certificate Manager with Total TLS or another certificate that covers the Preview hostname.
## Enable `workers.dev` Preview URLs Production and Preview `workers.dev` URLs are configured separately. Set `preview_urls` in your Wrangler configuration file, then run `npx wrangler deploy`. ```jsonc { "preview_urls": true } ``` ```toml preview_urls = true ``` If `preview_urls` is omitted, Wrangler does not change an existing Preview URL setting. If no setting exists, its initial value depends on `workers_dev`. Set `preview_urls` explicitly to change the Preview URL setting. 1. In the Cloudflare dashboard, go to **Workers & Pages** and select your Worker. [Go to **Workers & Pages** ↗](https://dash.cloudflare.com/?to=/:account/workers-and-pages) 2. On the **Domains** tab, under **Worker URL**, turn on **Preview**.![Domains tab showing workers.dev Preview URLs enabled with no custom domains configured](https://developers.cloudflare.com/cdn-cgi/image/onerror=redirect,width=2876,height=1488,format=webp/_astro/emptydomain.C1zwEW1b.png) ## Protect Preview content To restrict access to custom domain and `workers.dev` Preview URLs, use [Cloudflare Access](https://developers.cloudflare.com/workers/configuration/cloudflare-access/). This prevents unauthenticated users and crawlers from viewing your Preview. To keep a Preview public while discouraging search engine indexing, add an `X-Robots-Tag: noindex` response header. Cloudflare adds this header automatically to `workers.dev` Preview URLs, but not to custom domain Preview URLs. For static assets, add the header through a [`_headers` file](https://developers.cloudflare.com/workers/static-assets/headers/). For Worker-generated responses, add it directly in your Worker code. Was this helpful? YesNo ## On this page [![](https://developers.cloudflare.com/_astro/logo.te5VL_aD.svg)Docs](https://developers.cloudflare.com/) ```json {"@context":"https://schema.org","@type":"TechArticle","@id":"https://developers.cloudflare.com/workers/previews/custom-domains/#page","headline":"Custom domains","description":"Serve Preview URLs from custom domains and protect them with Cloudflare Access.","url":"https://developers.cloudflare.com/workers/previews/custom-domains/","inLanguage":"en","image":"https://developers.cloudflare.com/workers/previews/custom-domains/og.png?v=9983358f175f5b1c","dateModified":"2026-09-24","publisher":{"@type":"Organization","name":"Cloudflare","description":"One platform for your apps, agents, and workforce. Build, secure, and scale without managing infrastructure","url":"https://www.cloudflare.com/","sameAs":["https://github.com/cloudflare","https://www.linkedin.com/company/cloudflare","https://x.com/cloudflare"],"logo":{"@type":"ImageObject","url":"https://developers.cloudflare.com/logo.svg"},"address":{"@type":"PostalAddress","streetAddress":"101 Townsend St","addressLocality":"San Francisco","addressRegion":"CA","postalCode":"94107","addressCountry":"US"},"contactPoint":[{"@type":"ContactPoint","contactType":"Customer Support","url":"https://support.cloudflare.com/","availableLanguage":["English"]},{"@type":"ContactPoint","contactType":"Sales","url":"https://www.cloudflare.com/contact/","availableLanguage":["English"]}]},"isPartOf":{"@type":"WebSite","@id":"https://developers.cloudflare.com/#website","name":"Cloudflare Docs","url":"https://developers.cloudflare.com/"}} ```