0-RTT Connection Resumption
Zero round trip time resumption (0-RTT) improves performance for clients who have previously connected to your website, reducing latency for returning users. This feature is especially beneficial for those who frequently visit your application or connect over mobile networks.
We support 0-RTT for GET, HEAD, and OPTIONS requests, facilitating faster responses for these types of requests. Note that 0-RTT is not supported for POST requests.
In line with 0-RTT standards, we add the Early-Data: 1 header to 0-RTT requests, which allows origin servers to identify when a request has used 0-RTT resumption. Customers should be able to see the Early-Data: 1 header for any 0-RTT requests connecting to their origin.
For more information on 0-RTT, including its functionality and potential limitations, refer to our blog post ↗.
| Free | Pro | Business | Enterprise | |
|---|---|---|---|---|
Availability | Yes | Yes | Yes | Yes |
By default, 0-RTT Connection Resumption is not enabled on your Cloudflare application.
To enable 0-RTT Connection Resumption in the dashboard:
- Log in to your Cloudflare account ↗ and go to a specific domain.
- Navigate to Speed > Optimization.
- Navigate to the Protocol Optimization tab and under 0-RTT Connection Resumption, switch the toggle to On.
To adjust your 0-RTT Connection Resumption settings with the API, send a PATCH request with 0rtt as the setting name in the URI path, and the value parameter set to "on" or "off".