diff --git a/package.json b/package.json
index c715e8f..7df4ece 100644
--- a/package.json
+++ b/package.json
@@ -28,7 +28,7 @@
     "start": "bun run dev",
     "dev": "winterspec dev -p 3062",
     "build": "bun run build:bundle && bun run build:cli",
-    "build:bundle": "winterspec bundle -o dist/bundle.js",
+    "build:bundle": "bun scripts/build-bundle.ts",
     "build:cli": "tsup cli.ts --format esm --dts",
     "next:dev": "next dev",
     "format": "biome format --write .",
diff --git a/scripts/build-bundle.ts b/scripts/build-bundle.ts
new file mode 100644
index 0000000..bc089a3
--- /dev/null
+++ b/scripts/build-bundle.ts
@@ -0,0 +1,101 @@
+import esbuild from "esbuild"
+import { mkdir, readdir, writeFile } from "node:fs/promises"
+import path from "node:path"
+
+type RouteFile = {
+  absolutePath: string
+  relativePath: string
+  route: string
+}
+
+const projectRoot = path.resolve(import.meta.dir, "..")
+const routesDir = path.join(projectRoot, "routes")
+const outputPath = path.join(projectRoot, "dist", "bundle.js")
+
+const collectRouteFiles = async (
+  dir: string,
+  baseDir = dir,
+): Promise<Array<RouteFile>> => {
+  const entries = await readdir(dir, { withFileTypes: true })
+  const files: Array<RouteFile> = []
+
+  for (const entry of entries) {
+    const absolutePath = path.join(dir, entry.name)
+
+    if (entry.isDirectory()) {
+      files.push(...(await collectRouteFiles(absolutePath, baseDir)))
+      continue
+    }
+
+    if (!/\.(ts|tsx)$/.test(entry.name)) {
+      continue
+    }
+
+    const relativePath = path.relative(baseDir, absolutePath)
+    const posixRelativePath = relativePath.split(path.sep).join("/")
+    const routePath = `/${posixRelativePath}`
+    const route =
+      routePath.endsWith("/index.ts") || routePath.endsWith("/index.tsx")
+        ? routePath.replace(/\/index\.tsx*$/g, "")
+        : routePath.replace(/\.tsx*$/g, "")
+
+    files.push({
+      absolutePath,
+      relativePath: posixRelativePath,
+      route: route === "" ? "/" : route,
+    })
+  }
+
+  return files
+}
+
+const routes = (await collectRouteFiles(routesDir)).sort((a, b) =>
+  a.route.localeCompare(b.route),
+)
+
+const manifest = `
+import { getRouteMatcher } from "next-route-matcher"
+import { makeRequestAgainstWinterSpec } from "winterspec"
+
+${routes
+  .map(
+    ({ absolutePath }, index) =>
+      `import * as route_${index} from ${JSON.stringify(
+        absolutePath.replace(/\\/g, "/"),
+      )}`,
+  )
+  .join("\n")}
+
+const routeMapWithHandlers = {
+  ${routes
+    .map(({ route }, index) => `"${route}": route_${index}.default`)
+    .join(",\n  ")}
+}
+
+const winterSpec = {
+  routeMatcher: getRouteMatcher(Object.keys(routeMapWithHandlers)),
+  routeMapWithHandlers,
+  makeRequest: async (req, options) => makeRequestAgainstWinterSpec(winterSpec, options)(req),
+}
+
+export default winterSpec
+`
+
+const result = await esbuild.build({
+  stdin: {
+    contents: manifest,
+    resolveDir: routesDir,
+    loader: "ts",
+  },
+  bundle: true,
+  format: "esm",
+  write: false,
+  sourcemap: "inline",
+  platform: "node",
+  packages: "external",
+})
+
+await mkdir(path.dirname(outputPath), { recursive: true })
+await writeFile(outputPath, result.outputFiles[0].text)
+
+console.log(`Built bundle to ${path.relative(projectRoot, outputPath)}`)