diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 61b6f174..fe7fe6dc 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -98,7 +98,7 @@ jobs:
           node-version: "22"
       - uses: astral-sh/setup-uv@v5
       - name: Install wrangler
-        run: npm install -g wrangler@3
+        run: npm install -g wrangler@4
       - name: Generate test secrets
         # Required by `load_config` in src/config.rs (`JwtSigner::from_pem` and
         # `TokenKey::from_base64` validate at startup). The signing key is a
diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
index 39261721..2ea48fb5 100644
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@@ -91,7 +91,7 @@ jobs:
           name: worker-build-${{ github.run_id }}-${{ github.run_attempt }}
           path: build/
       # Installed separately so the package resolution is uncredentialed too.
-      - run: npm install -g wrangler@3
+      - run: npm install -g wrangler@4
 
       - name: Override service bindings
         if: inputs.service_overrides != ''
diff --git a/.github/workflows/preview.yml b/.github/workflows/preview.yml
index 4aac62be..860fe623 100644
--- a/.github/workflows/preview.yml
+++ b/.github/workflows/preview.yml
@@ -76,7 +76,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       # Installed separately so the package resolution is uncredentialed too.
-      - run: npm install -g wrangler@3
+      - run: npm install -g wrangler@4
       - name: Delete preview worker
         env:
           CLOUDFLARE_API_TOKEN: ${{ secrets.CLOUDFLARE_API_TOKEN }}
diff --git a/README.md b/README.md
index f502c343..088bf527 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ The proxy supports `GET`, `HEAD`, and S3-compatible `LIST` operations with anony
 ```sh
 rustup target add wasm32-unknown-unknown
 cargo install worker-build@0.7.5
-npm install -g wrangler@3
+npm install -g wrangler@4
 ```
 
 ### Run Locally
@@ -120,7 +120,7 @@ Set in `wrangler.toml` or via the Cloudflare dashboard:
 
 | Binding              | Kind        | Description                                                                                                                                  |
 | -------------------- | ----------- | -------------------------------------------------------------------------------------------------------------------------------------------- |
-| `KEY_EXCHANGE_LIMIT` | `ratelimit` | Per-client-IP limit on API-key exchanges at `/.sts` (ADR-013). Declared under `[[unsafe.bindings]]` in every `wrangler*.toml`; a deployment without it logs an error and exchanges without a limit |
+| `KEY_EXCHANGE_LIMIT` | `ratelimit` | Per-client-IP limit on API-key exchanges at `/.sts` (ADR-013). Declared under `[[ratelimits]]` in every `wrangler*.toml`; a deployment without it logs an error and exchanges without a limit |
 
 ### API keys
 
diff --git a/wrangler.preview.toml b/wrangler.preview.toml
index 323e9f6f..b5ae42fb 100644
--- a/wrangler.preview.toml
+++ b/wrangler.preview.toml
@@ -49,8 +49,7 @@ binding = "PUBLIC_LOG_STREAM"
 service = "public-log-stream-staging"
 
 # API-key exchange rate limit, per client IP; see wrangler.toml.
-[[unsafe.bindings]]
+[[ratelimits]]
 name = "KEY_EXCHANGE_LIMIT"
-type = "ratelimit"
 namespace_id = "1003"
 simple = { limit = 100, period = 60 }
diff --git a/wrangler.toml b/wrangler.toml
index 6b10f65d..da445edf 100644
--- a/wrangler.toml
+++ b/wrangler.toml
@@ -71,9 +71,8 @@ service = "public-log-stream"
 # API one lookup for a distinct key, so this bounds a flood of junk keys from
 # one place; a legitimate client exchanges about once a session, so even a
 # cluster behind one NAT stays far under it. See src/lib.rs `api_key_exchange`.
-[[unsafe.bindings]]
+[[ratelimits]]
 name = "KEY_EXCHANGE_LIMIT"
-type = "ratelimit"
 namespace_id = "1001"
 simple = { limit = 100, period = 60 }
 
@@ -100,9 +99,8 @@ dataset = "source_data_proxy_staging"
 binding = "PUBLIC_LOG_STREAM"
 service = "public-log-stream-staging"
 
-[[env.staging.unsafe.bindings]]
+[[env.staging.ratelimits]]
 name = "KEY_EXCHANGE_LIMIT"
-type = "ratelimit"
 namespace_id = "1002"
 simple = { limit = 100, period = 60 }