diff --git a/package.json b/package.json
index a719127..279d7bb 100644
--- a/package.json
+++ b/package.json
@@ -12,8 +12,9 @@
     "dev": "vite dev",
     "dev:port": "vite dev --port",
     "prebuild": "bun run generate:changelog && bun run scripts/copy-docs-images.cjs",
-    "build": "NODE_OPTIONS=--max-old-space-size=8192 vite build && bun run scripts/generate-static-cache.ts && bun run scripts/generate-search-index.ts",
+    "build": "NODE_OPTIONS=--max-old-space-size=8192 vite build && bun run scripts/generate-static-assets.ts",
     "build:cf": "bun run build",
+    "measure:build": "bun run scripts/measure-build.ts",
     "build:cf:staging": "NODE_OPTIONS=--max-old-space-size=8192 CLOUDFLARE_ENV=staging bun run build",
     "sync:mixedbread": "mxbai vs sync $MIXEDBREAD_STORE_ID './content/docs' --ci",
     "preview": "vite preview",
diff --git a/scripts/generate-static-assets.ts b/scripts/generate-static-assets.ts
new file mode 100644
index 0000000..c8cc816
--- /dev/null
+++ b/scripts/generate-static-assets.ts
@@ -0,0 +1,133 @@
+/**
+ * Post-build: generates static cache JSON files + search index.
+ *
+ * Replaces the previous two-step pipeline (`generate-static-cache.ts` +
+ * `generate-search-index.ts`), which each spun up a fresh Vite SSR server
+ * and re-evaluated the same fumadocs MDX collection. We do that work once
+ * here and run the cache-file emission in parallel with the search-index
+ * build, saving the cost of one full Vite cold-start (~5-7s locally,
+ * ~15-20s on Cloudflare's slower builders).
+ *
+ * Usage:  bun run scripts/generate-static-assets.ts
+ * Called automatically as part of `bun run build`.
+ */
+
+import { createServer } from "vite";
+import fs from "node:fs/promises";
+import path from "node:path";
+import react from "@vitejs/plugin-react";
+import tsConfigPaths from "vite-tsconfig-paths";
+import mdx from "fumadocs-mdx/vite";
+
+const ROOT = process.cwd();
+const DIST_CLIENT = path.join(ROOT, "dist/client");
+const CACHE_DIR = path.join(DIST_CLIENT, "docs/__sfn_cache");
+const SEARCH_DIR = path.join(DIST_CLIENT, "docs");
+
+async function generateStaticCache(server: Awaited<ReturnType<typeof createServer>>) {
+  const start = performance.now();
+  const { source } = await server.ssrLoadModule("./src/lib/source");
+  const { gitConfig } = await server.ssrLoadModule("./src/lib/layout.shared.tsx");
+  const { buildCanonicalUrl, SITE_NAME, DEFAULT_DESCRIPTION } = await server.ssrLoadModule(
+    "./src/lib/metadata",
+  );
+
+  const pageTree = await source.serializePageTree(source.getPageTree());
+  const pages = source.getPages() as Array<{
+    slugs: string[];
+    url: string;
+    path: string;
+    data: { title?: string; description?: string };
+  }>;
+
+  await fs.mkdir(CACHE_DIR, { recursive: true });
+
+  let count = 0;
+  await Promise.all(
+    pages.map(async (page) => {
+      const cacheKey = page.slugs.length === 0 ? "_index" : page.slugs.join("/");
+      const pageTitle = page.data.title || SITE_NAME;
+      const pageDescription = page.data.description || DEFAULT_DESCRIPTION;
+      const canonicalUrl = buildCanonicalUrl(page.url);
+      const githubUrl = `https://github.com/${gitConfig.user}/${gitConfig.repo}/blob/${gitConfig.branch}/content/docs/${page.path}`;
+
+      const payload = {
+        url: page.url,
+        path: page.path,
+        githubUrl,
+        pageTitle,
+        pageDescription,
+        canonicalUrl,
+        pageTree,
+      };
+
+      const filePath = path.join(CACHE_DIR, `${cacheKey}.json`);
+      await fs.mkdir(path.dirname(filePath), { recursive: true });
+      await fs.writeFile(filePath, JSON.stringify(payload));
+      count++;
+    }),
+  );
+
+  const ms = performance.now() - start;
+  console.log(
+    `  ✓ ${count} cache files written to ${path.relative(ROOT, CACHE_DIR)}/ (${ms.toFixed(0)}ms)`,
+  );
+}
+
+async function generateSearchIndex(server: Awaited<ReturnType<typeof createServer>>) {
+  const start = performance.now();
+  const { buildDocsSearchDocuments } = await server.ssrLoadModule("./src/lib/search");
+  const { SEARCH_INDEX_FILENAME } = await server.ssrLoadModule("./src/lib/search.shared");
+  const { buildStaticSearchIndex, exportStaticSearchIndex } = await server.ssrLoadModule(
+    "./src/lib/search-index",
+  );
+
+  const outputPath = path.join(SEARCH_DIR, SEARCH_INDEX_FILENAME);
+  const documents = await buildDocsSearchDocuments();
+
+  await fs.rm(path.join(SEARCH_DIR, "assets", "search"), { force: true, recursive: true });
+  await fs.mkdir(SEARCH_DIR, { recursive: true });
+  const index = buildStaticSearchIndex(documents);
+  const payload = JSON.stringify(await exportStaticSearchIndex(index));
+
+  await fs.writeFile(outputPath, payload);
+
+  const ms = performance.now() - start;
+  const bytes = Buffer.byteLength(payload);
+  console.log(
+    `  ✓ search index written to ${path.relative(ROOT, outputPath)} ` +
+      `(${bytes.toLocaleString()} bytes, ${ms.toFixed(0)}ms)`,
+  );
+}
+
+async function main() {
+  const overallStart = performance.now();
+  console.log("Generating static assets (cache + search index)…");
+
+  const server = await createServer({
+    configFile: false,
+    logLevel: "error",
+    server: { port: 0, host: "127.0.0.1" },
+    resolve: {
+      alias: { "@": path.resolve(ROOT, "./src") },
+    },
+    plugins: [
+      mdx(await import("../source.config")),
+      tsConfigPaths({ projects: ["./tsconfig.json"] }),
+      react(),
+    ],
+  });
+
+  try {
+    await Promise.all([generateStaticCache(server), generateSearchIndex(server)]);
+    const total = performance.now() - overallStart;
+    console.log(`Static assets generated in ${(total / 1000).toFixed(2)}s`);
+  } finally {
+    await server.close();
+  }
+}
+
+main().catch((err) => {
+  console.error("Static asset generation failed:", err);
+  process.exit(1);
+});
diff --git a/scripts/measure-build.ts b/scripts/measure-build.ts
new file mode 100644
index 0000000..c5bcd2f
--- /dev/null
+++ b/scripts/measure-build.ts
@@ -0,0 +1,179 @@
+/**
+ * Measures Cloudflare build time, broken down by phase.
+ *
+ * Usage:
+ *   bun run scripts/measure-build.ts                # clean run, all phases
+ *   bun run scripts/measure-build.ts --no-clean     # keep prior dist/.source
+ *   bun run scripts/measure-build.ts --skip-changelog
+ *   bun run scripts/measure-build.ts --label=baseline
+ *
+ * Phases match `bun run build:cf` (= `bun run build`):
+ *   1. prebuild: generate-changelog          (skippable)
+ *   2. prebuild: copy-docs-images
+ *   3. vite build                            (the big one — TanStack Start prerender)
+ *   4. generate-static-cache
+ *   5. generate-search-index
+ *
+ * Each phase runs as its own child process so timings are isolated.
+ * Results are written to `.context/build-timings/<ISO>.json`.
+ */
+
+import { spawn } from "node:child_process";
+import fs from "node:fs/promises";
+import path from "node:path";
+
+const args = new Set(process.argv.slice(2));
+let label = "run";
+for (const arg of args) {
+  if (arg.startsWith("--label=")) {
+    label = arg.slice("--label=".length);
+  }
+}
+
+const skipClean = args.has("--no-clean");
+const skipChangelog = args.has("--skip-changelog");
+const onlyClean = args.has("--clean-only");
+
+const ROOT = process.cwd();
+const TIMINGS_DIR = path.join(ROOT, ".context", "build-timings");
+
+interface PhaseResult {
+  name: string;
+  ms: number;
+  exitCode: number | null;
+  skipped?: boolean;
+}
+
+function runPhase(name: string, cmd: string, cmdArgs: string[]): Promise<PhaseResult> {
+  return new Promise((resolve) => {
+    const start = performance.now();
+    process.stdout.write(`\n▶ [${name}] ${cmd} ${cmdArgs.join(" ")}\n`);
+    const child = spawn(cmd, cmdArgs, {
+      cwd: ROOT,
+      stdio: "inherit",
+      env: {
+        ...process.env,
+        NODE_OPTIONS: process.env.NODE_OPTIONS ?? "--max-old-space-size=8192",
+      },
+    });
+    child.on("exit", (code) => {
+      const ms = performance.now() - start;
+      resolve({ name, ms, exitCode: code });
+    });
+  });
+}
+
+async function clean(): Promise<PhaseResult> {
+  const start = performance.now();
+  process.stdout.write("\n▶ [clean] rm dist + .source + node_modules/.vite\n");
+  const targets = [
+    path.join(ROOT, "dist"),
+    path.join(ROOT, ".source"),
+    path.join(ROOT, "node_modules", ".vite"),
+  ];
+  for (const target of targets) {
+    await fs.rm(target, { recursive: true, force: true });
+  }
+  const ms = performance.now() - start;
+  return { name: "clean", ms, exitCode: 0 };
+}
+
+function fmt(ms: number) {
+  if (ms < 1000) return `${ms.toFixed(0)}ms`;
+  return `${(ms / 1000).toFixed(2)}s`;
+}
+
+function printTable(rows: PhaseResult[], totalMs: number) {
+  const headers = ["Phase", "Duration", "% Total", "Status"];
+  const body = rows.map((row) => [
+    row.name,
+    row.skipped ? "—" : fmt(row.ms),
+    row.skipped ? "—" : `${((row.ms / totalMs) * 100).toFixed(1)}%`,
+    row.skipped ? "skipped" : row.exitCode === 0 ? "ok" : `exit ${row.exitCode}`,
+  ]);
+  body.push(["TOTAL", fmt(totalMs), "100.0%", ""]);
+
+  const widths = headers.map((header, i) =>
+    Math.max(header.length, ...body.map((row) => row[i].length)),
+  );
+  const formatRow = (row: string[]) =>
+    row.map((cell, i) => cell.padEnd(widths[i])).join("  ");
+
+  console.log("");
+  console.log(formatRow(headers));
+  console.log(widths.map((w) => "-".repeat(w)).join("  "));
+  for (const row of body) console.log(formatRow(row));
+}
+
+async function main() {
+  const totalStart = performance.now();
+  const results: PhaseResult[] = [];
+
+  if (!skipClean) {
+    results.push(await clean());
+  }
+  if (onlyClean) {
+    const totalMs = performance.now() - totalStart;
+    printTable(results, totalMs);
+    return;
+  }
+
+  if (skipChangelog) {
+    results.push({ name: "generate-changelog", ms: 0, exitCode: 0, skipped: true });
+  } else {
+    results.push(await runPhase("generate-changelog", "bun", [
+      "run",
+      "scripts/generate-changelog.ts",
+    ]));
+  }
+
+  results.push(await runPhase("copy-docs-images", "bun", [
+    "run",
+    "scripts/copy-docs-images.cjs",
+  ]));
+
+  results.push(await runPhase("vite build", "bunx", ["vite", "build"]));
+
+  results.push(await runPhase("generate-static-assets", "bun", [
+    "run",
+    "scripts/generate-static-assets.ts",
+  ]));
+
+  const totalMs = performance.now() - totalStart;
+  const failed = results.find((r) => !r.skipped && r.exitCode !== 0);
+
+  printTable(results, totalMs);
+
+  await fs.mkdir(TIMINGS_DIR, { recursive: true });
+  const timestamp = new Date().toISOString().replace(/[:.]/g, "-");
+  const outFile = path.join(TIMINGS_DIR, `${timestamp}-${label}.json`);
+  await fs.writeFile(
+    outFile,
+    JSON.stringify(
+      {
+        label,
+        timestamp,
+        totalMs,
+        results,
+        env: {
+          skipClean,
+          skipChangelog,
+          node: process.version,
+        },
+      },
+      null,
+      2,
+    ),
+  );
+  console.log(`\nSaved → ${path.relative(ROOT, outFile)}`);
+
+  if (failed) {
+    console.error(`\nPhase "${failed.name}" failed (exit ${failed.exitCode}).`);
+    process.exit(1);
+  }
+}
+
+main().catch((err) => {
+  console.error("Build measurement failed:", err);
+  process.exit(1);
+});
diff --git a/source.config.ts b/source.config.ts
index 0710dda..4bf3f8d 100644
--- a/source.config.ts
+++ b/source.config.ts
@@ -14,7 +14,12 @@ const isDevelopment = process.env.NODE_ENV === "development";
 export const docs = defineDocs({
   dir: "content/docs",
   docs: {
-    async: isDevelopment,
+    // Async MDX collection: each page's compiled MDX is a dynamic import,
+    // not bundled into the SSR/server entry. Without this the server bundle
+    // inlined all ~530 docs (~30 MB) and Vite's SSR transform took ~33s.
+    // Pages are still fully prerendered to static HTML at build time, so
+    // there's no end-user impact.
+    async: true,
     postprocess: {
       includeProcessedMarkdown: true,
     },
@@ -22,6 +27,12 @@ export const docs = defineDocs({
 });
 
 export default defineConfig({
+  // Persist the MDX-compilation cache (shiki highlighting + remark pipeline)
+  // between builds. Lives inside node_modules/, which Cloudflare Pages
+  // caches between deploys when build caching is enabled. Each MDX file is
+  // hashed and only re-processed when its content changes; on a deploy
+  // touching a handful of pages the rest skip transform entirely.
+  experimentalBuildCache: "node_modules/.cache/fumadocs-mdx",
   mdxOptions: {
     // Shiki highlighting is one of the most expensive parts of the MDX pipeline.
     // Keep it in builds, but skip it in local dev so first-page SSR doesn't have
diff --git a/vite.config.ts b/vite.config.ts
index 50450ac..12d16d2 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -5,7 +5,8 @@ import tsConfigPaths from "vite-tsconfig-paths";
 import tailwindcss from "@tailwindcss/vite";
 import mdx from "fumadocs-mdx/vite";
 import { cloudflare } from "@cloudflare/vite-plugin";
-import path from "path";
+import os from "node:os";
+import path from "node:path";
 
 /**
  * Only bundle the Shiki language packs actually used in docs.
@@ -69,7 +70,10 @@ export default defineConfig({
       },
       prerender: {
         enabled: true,
-        concurrency: 3,
+        // Was hardcoded to 3 (suspected OOM defense). With
+        // --max-old-space-size=8192 set in `bun run build` we have plenty of
+        // headroom — let it use whatever the builder actually has.
+        concurrency: os.cpus().length,
         filter: (page) => {
           return !(
             page.path === "/sdk" ||