diff --git a/AGENTS.md b/AGENTS.md
index 27391f9..b3aa6c2 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -6,7 +6,7 @@ See also: [ARCHITECTURE.md](./ARCHITECTURE.md) for project structure and data fl
 
 ## Project Overview
 
-Netlify Cache Inspector is a Nuxt 4 web app for inspecting and comparing HTTP cache headers on Netlify sites. Users submit a URL, the server fetches it with Netlify debug headers (`x-nf-debug-logging: 1`), and the frontend displays structured cache analysis. Multiple runs can be compared side-by-side with hover-based diffing.
+Netlify Cache Inspector is a Nuxt 5 web app for inspecting and comparing HTTP cache headers on Netlify sites. Users submit a URL, the server fetches it with Netlify debug headers (`x-nf-debug-logging: 1`), and the frontend displays structured cache analysis. Multiple runs can be compared side-by-side with hover-based diffing.
 
 ## Commands
 
@@ -31,7 +31,7 @@ Package manager is **pnpm** (pinned in `packageManager` field). Enable via `core
 
 ## Architecture
 
-**Nuxt 4** with `future: { compatibilityVersion: 4 }` — frontend code lives under `app/` (not project root).
+**Nuxt 5** with `future: { compatibilityVersion: 5 }` — frontend code lives under `app/` (not project root).
 
 ### Data Flow
 
diff --git a/ARCHITECTURE.md b/ARCHITECTURE.md
index a71d5a0..1d6a46a 100644
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -2,7 +2,7 @@
 
 ## Project structure
 
-Nuxt 4, with the new `app/` directory structure.
+Nuxt 5, with the `app/` directory structure.
 
 ```
 app/
diff --git a/README.md b/README.md
index 2710299..ded047f 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ This site deploys automatically to Netlify.
 
 ## Tech stack
 
-- [Nuxt 4](https://nuxt.com) (Vue 3, file-based routing, server API routes)
+- [Nuxt 5](https://nuxt.com) (Vue 3, file-based routing, server API routes)
 - [UnoCSS](https://unocss.dev) (utility CSS, dark mode, custom theme)
 - [Netlify Blobs](https://docs.netlify.com/blobs/overview/) (run persistence)
 - [Vitest](https://vitest.dev) + [Vue Test Utils](https://test-utils.vuejs.org) (testing)
diff --git a/knip.config.ts b/knip.config.ts
index f54e1f7..6181075 100644
--- a/knip.config.ts
+++ b/knip.config.ts
@@ -1,8 +1,7 @@
 import type { KnipConfig } from 'knip'
 
 export default {
-  entry: ['oxlint.config.ts'],
-  // knip's Nuxt plugin doesn't support the Nuxt 4 app/ directory convention yet.
+  // knip's Nuxt plugin doesn't support the Nuxt 5 app/ directory convention yet.
   // Note: custom entry replaces (not merges with) the plugin defaults.
   nuxt: {
     entry: [
diff --git a/nuxt.config.ts b/nuxt.config.ts
index ea913df..2e83c31 100644
--- a/nuxt.config.ts
+++ b/nuxt.config.ts
@@ -57,6 +57,6 @@ export default defineNuxtConfig({
       },
     },
   },
-  future: { compatibilityVersion: 4 },
-  compatibilityDate: '2024-09-13',
+  future: { compatibilityVersion: 5 },
+  compatibilityDate: '2026-03-24',
 })
diff --git a/package.json b/package.json
index 78337e0..b540e51 100644
--- a/package.json
+++ b/package.json
@@ -22,6 +22,7 @@
     "@netlify/blobs": "^10.7.0",
     "@netlify/nuxt": "0.2.36",
     "date-fns": "^4.1.0",
+    "h3": "^1.15.0",
     "highlight.js": "^11.11.1",
     "nuxt": "^4.4.2",
     "vue": "^3.5.29",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index c65502e..23e7340 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -17,6 +17,9 @@ importers:
       date-fns:
         specifier: ^4.1.0
         version: 4.1.0
+      h3:
+        specifier: ^1.15.0
+        version: 1.15.6
       highlight.js:
         specifier: ^11.11.1
         version: 11.11.1
diff --git a/server/api/inspect-url.post.ts b/server/api/inspect-url.post.ts
index 998e95c..a53aecf 100644
--- a/server/api/inspect-url.post.ts
+++ b/server/api/inspect-url.post.ts
@@ -1,4 +1,5 @@
 import { createHash } from 'crypto'
+import { createError, defineEventHandler, readBody } from 'h3'
 import { saveRun } from '~server/db'
 
 const generateRunId = (url: string, timestamp: number): string =>
diff --git a/server/api/runs/[runId].ts b/server/api/runs/[runId].ts
index 00d62c3..910ef25 100644
--- a/server/api/runs/[runId].ts
+++ b/server/api/runs/[runId].ts
@@ -1,3 +1,4 @@
+import { createError, defineEventHandler, getRouterParam } from 'h3'
 import { getRun } from '~server/db'
 
 export default defineEventHandler(async (event) => {