Examples
45 examples
- Deliver an HTML page from an HTML string directly inside the Worker script.
- Return JSON directly from a Worker script, useful for building APIs and middleware.
- Send a request to a remote server, read HTML from the response, and serve that HTML.
- Send a GET request and read in JSON from the response. Use to fetch external data.
- Redirect requests from one URL to another or from one set of URLs to another set.
- Access custom Cloudflare properties and control how Cloudflare features are applied to every request.
- Respond to the Worker request with the response from another website (example.com in this example).
- Allow a client to request static assets while waiting for the HTML response.
- Set up an A/B test by controlling what response is served based on cookies. This version supports passing the request through to test and control on the origin, bypassing random assignment.
- Send two GET request to two urls and aggregates the responses into one response.
- Example of how to add, change, or delete headers sent in a request or returned in a response.
- Allow or deny a request based on a known pre-shared key in a header. This is not meant to replace the WebCrypto API.
- Inspects the incoming request’s TLS version and blocks if under TLSv1.2.
- Resolve requests to your domain to a set of proxy third-party origin URLs.
- Redirect requests to certain URLs based on a mapped object to the request’s URL.
- Cache POST requests using the Cache API.
- Send Additional Cache Tags using Workers
- Determine how to cache a resource by setting TTLs, custom cache keys, and cache headers in a fetch request.
- Return a response based on the incoming request’s URL, HTTP method, User Agent, IP address, ASN or device type.
- Given the cookie name, get the value of a cookie. You can also use cookies for A/B testing.
- Add the necessary CORS headers to a third party API response.
- Redirect a response based on the country code in the header of a visitor.
- Set up custom domain for Images using a Worker or serve images using a prefix path and Cloudflare registered domain.
- Protect sensitive data to prevent data loss, and send alerts to a webhooks server in the event of a data breach.
- Send debugging information in an errored response to a logging service.
- Personalize website styling based on localized user time.
- Get all geolocation data fields and display them in HTML.
- Fetch weather data from an API using the user’s geolocation data.
- Block other websites from linking to your content. This is useful for protecting images.
- Shows how to restrict access using the HTTP Basic schema.
- Examine the contents of a Headers object by logging to console with a Map.
- Create a modified request with edited properties based off of an incoming request.
- Fetch and modify response properties which are immutable by creating a copy first.
- Set multiple Cron Triggers on three different schedules.
- Send a POST request with JSON data. Use to share data with external servers.
- Serve an HTML form, then read POST requests. Use also to read JSON or POST data from an incoming request.
- Rewrite URL links in HTML using the HTMLRewriter. This is useful for JAMstack websites.
- Set common security headers (X-XSS-Protection, X-Frame-Options, X-Content-Type-Options, Permissions-Policy, Referrer-Policy, Strict-Transport-Security, Content-Security-Policy).
- Set a Cron Trigger for your Worker.
- Verify a signed request using the HMAC and SHA-256 algorithms or return a 403.
- Use the OpenAI v4 SDK to stream responses from OpenAI.
- Inject Turnstile implicitly into HTML elements using the HTMLRewriter runtime API.
- Use the Cache API to store responses in Cloudflare’s cache.
- Protect against timing attacks by safely comparing values using
timingSafeEqual. - Use the WebSockets API to communicate in real time with your Cloudflare Workers.