Actix 4.15.0

Actix-web 4.15.0 dropped on August 21, 2026, and it's all about responses — fixing them, shaping them, and shipping them exactly how you want. Two headline moves this time, both with serious "your middleware just got stronger" energy.

✨ Middleware Magic — Error::add_response_mapper()

The big one: Error::add_response_mapper() is here. It lets middleware modify error-generated responses before they're actually sent down the wire. No more being stuck with the default error shape — now you can intercept, re-wrap, and send the exact payload your frontend (or your contract) expects. If you've ever wanted to customize how a 500 or a validation failure leaves the server, this is your hook.

🧹 Sous Chef Cleanup — io-uring, Out the Door

On the cutting-room floor this release: the experimental experimental-io-uring crate feature has been removed. If you were building against that experimental flag, this is your sign to update your Cargo setup and drop the feature from your manifest. Experimental means temporary, and its time is up.

⚙️ Upgrade at Your Own Pace

Update path is straightforward: bump your Cargo.toml to actix-web = "4.15.0". If you used the experimental-io-uring feature, remove it before you build or you'll hit a compile error. For everyone else, this is a clean, low-friction bump.

↗️ Go grab it — middleware that shapes responses, and one less experimental experiment. Don't sleep on this one. 🔗