`, favicon, and body of `Root()` to\nmatch your app's existing `index.html`, and stamp anything else your shell\nreferences directly (images, css) with `immutableFileUrl()`.\n\n1. Create `frontend/root.tsx`:\n\n```tsx\n/** @jsxImportSource npm:hono@4/jsx */\nimport { raw } from \"npm:hono@4/html\";\nimport { immutableFileUrl } from \"https://esm.town/v/std/utils/index.ts\";\n\n// The HTML shell for the app. It is never cached, so immutableFileUrl can stamp\n// the current val version into each asset URL — the browser caches those\n// immutably, and publishing the val changes the URLs, refetching exactly once.\nexport function Root() {\n return (\n <>\n {raw(\"<!DOCTYPE html>\")}\n <html lang=\"en\">\n <head>\n <meta charSet=\"UTF-8\" />\n <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n <title>React Hono Val Town Starter

[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8,"_9":10},"actionData","errors","root",{"_309":310,"_311":312},"routes/_app.x.$handle.$name",{"_11":12,"_13":14,"_15":-7,"_18":19,"_17":-7,"_233":-5,"_20":234,"_22":235,"_236":237,"_238":239,"_26":240,"_24":241,"_242":-5,"_243":-5,"_244":52,"_245":246,"_247":43,"_248":-5,"_249":-5,"_250":251},"routes/_app.x.$handle.$name.code.$",{"_11":12,"_13":14,"_15":16,"_17":-7,"_18":19,"_20":21,"_22":23,"_24":25,"_26":27,"_28":-5,"_29":-5,"_30":-5,"_31":-5,"_32":-5},"handle","testprojects","name","my-chatbot","branchName","main","version","path","index.ts","project",{"_33":175,"_13":14,"_44":176,"_177":-5,"_178":52,"_179":180,"_181":180,"_182":183,"_184":-5,"_185":186,"_187":36,"_188":43,"_189":-5,"_190":-5,"_191":68,"_192":193,"_194":195,"_196":197,"_198":199,"_200":-5,"_201":202,"_203":202,"_204":205,"_206":205,"_207":205,"_208":202,"_209":202,"_210":211,"_212":213,"_214":215,"_216":52},"tree",[55,56,57,58],"file",{"_33":34,"_13":19,"_35":36,"_37":-5,"_38":39,"_40":41,"_42":43,"_44":45,"_17":46,"_47":48,"_49":50,"_51":52,"_53":14,"_18":54},"contents",[],"upstream","pull","ahead","behind","envVars","id","6de2bab7-b80f-4418-ab73-6e6b484c89f0","fileId","01a09f74-2eca-779e-bf47-465c91838701","parentId","branchId","ee78e4df-9d49-44fe-a93c-3490446f2d42","branchVersion",21,"latest",true,"createdAt",["D",1789381923815],4,"fileType","http","content","import { parseVal, serveImmutableFile } from \"https://esm.town/v/std/utils/index.ts\";\nimport { Hono } from \"npm:hono\";\nimport { streamSSE } from \"npm:hono@4/streaming\";\nimport { Root } from \"./frontend/root.tsx\";\n\nconst app = new Hono();\n\n// Serve the (never-cached) HTML shell at the root /\napp.get(\"/\", (c) => c.html(Root()));\n\n// Serve frontend files at the version-addressed URLs Root() stamps, cached immutably\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\n\n// View source redirect\napp.get(\"/source\", (c) => c.redirect(parseVal().links.self.val));\n\n// Chat endpoint — proxies a streaming OpenRouter chat completion as SSE\napp.post(\"/api/chat\", async (c) => {\n const apiKey = Deno.env.get(\"OPENROUTER_API_KEY\");\n if (!apiKey) {\n return c.json({ error: \"OPENROUTER_API_KEY is not set on this val\" }, 500);\n }\n const { messages, model: requestedModel } = await c.req.json();\n const model = requestedModel || Deno.env.get(\"OPENROUTER_MODEL\") || \"openai/gpt-4o-mini\";\n return streamSSE(c, async (stream) => {\n const upstream = await fetch(\"https://openrouter.ai/api/v1/chat/completions\", {\n method: \"POST\",\n headers: {\n \"Content-Type\": \"application/json\",\n Authorization: `Bearer ${apiKey}`,\n // Optional but recommended by OpenRouter — no tracking unless you set these\n \"HTTP-Referer\": \"https://my-chatbot.val.run\",\n \"X-Title\": \"Val Town Chatbot\",\n },\n body: JSON.stringify({ model, messages, stream: true }),\n });\n if (!upstream.ok || !upstream.body) {\n const text = await upstream.text().catch(() => \"\");\n throw new Error(`OpenRouter error ${upstream.status}: ${text.slice(0, 300)}`);\n }\n const reader = upstream.body.getReader();\n const decoder = new TextDecoder();\n let buffer = \"\";\n while (true) {\n const { done, value } = await reader.read();\n if (done) break;\n buffer += decoder.decode(value, { stream: true });\n const lines = buffer.split(\"\\n\");\n buffer = lines.pop() ?? \"\";\n for (const line of lines) {\n const trimmed = line.trim();\n if (!trimmed.startsWith(\"data:\")) continue;\n const data = trimmed.slice(5).trim();\n if (data === \"[DONE]\") return;\n try {\n const json = JSON.parse(data);\n const delta = json.choices?.[0]?.delta?.content;\n if (delta) {\n await stream.writeSSE({ data: JSON.stringify({ delta }) });\n }\n } catch {\n /* ignore malformed chunks */\n }\n }\n }\n await stream.close();\n });\n});\n\n// Unwrap and rethrow Hono errors as the original error\n// If you delete this, all errors will be \"Internal Server Error\"\napp.onError((err) => Promise.reject(err));\n\n// HTTP vals expect an exported \"fetch handler\"\n// This is how you \"run the server\" in Val Town with Hono\nexport default app.fetch;\n","deleted",false,"label",[19],{"_33":79,"_13":80,"_35":81,"_37":-5,"_38":39,"_40":66,"_42":43,"_44":82,"_17":68,"_47":83,"_49":-5,"_51":52,"_53":-5,"_60":84,"_18":85},{"_33":72,"_13":73,"_35":74,"_37":-5,"_38":39,"_40":66,"_42":43,"_44":75,"_17":68,"_47":24,"_49":76,"_51":52,"_53":-5,"_60":77,"_18":78},{"_33":63,"_13":64,"_35":65,"_37":-5,"_38":39,"_40":66,"_42":43,"_44":67,"_17":68,"_47":24,"_49":69,"_51":52,"_53":-5,"_60":70,"_18":71},{"_33":34,"_13":19,"_35":36,"_37":-5,"_38":39,"_40":41,"_42":43,"_44":59,"_17":46,"_47":48,"_49":50,"_51":52,"_53":14,"_60":61,"_18":62},["D",1789381923815],"children",[],[19],"ef9e0035-a6aa-4695-8962-cafea439c74b","README.md","01a09f74-2eca-779e-bf47-439f9bd87169",1,["D",1789381586527],0,"# React + Hono Starter\n\nA minimal starter template for building client-side React apps with a Hono\nbackend on Val Town. Click **Remix** to get your own copy.\n\n## Picking a starter\n\n| Starter | When to pick it |\n| --- | --- |\n| [`basic-html-starter`](https://www.val.town/x/templates/basic-html-starter) | Static HTML pages. Sprinkle of vanilla JS. No server-side rendering. |\n| [`hono-jsx-starter`](https://www.val.town/x/templates/hono-jsx-starter) | Dynamic server-rendered HTML with JSX. API routes. No React, no SPA. |\n| **[`react-hono-starter`](https://www.val.town/x/templates/react-hono-starter)** *(you're here)* | Client-side React SPA with a Hono API backend. |\n\n**Want to build UI?** Start writing React components in\n[`frontend/components/`](/frontend/components/). Import them into `App.tsx` and\nyou're good to go. Styling is [Twind](https://twind.style/) — just use Tailwind\nutility classes, zero config.\n\n**Want to add an API?** Add routes in [`index.ts`](/index.ts) (there's a\ncommented-out example). Fetch them from your React components.\n\n## Architecture\n\n```mermaid\ngraph LR\n Browser -->|\"GET /\"| Hono[\"index.ts
(Hono server)\"]\n Hono -->|serves| HTML[\"root.tsx\"]\n HTML -->|loads| Entry[\"index.tsx\"]\n Entry -->|renders| App[\"App.tsx\"]\n App -->|renders| Counter[\"Counter.tsx\"]\n```\n\n## File structure\n\n```\nindex.ts ← Hono backend (serves frontend + API routes)\nfrontend/\n root.tsx ← HTML shell (stamps immutable asset URLs)\n index.tsx ← React entrypoint (mounts )\n favicon.svg ← App icon\n components/\n App.tsx ← Root component (layout + view source link)\n Counter.tsx ← Example component with state\n```\n\n## How it works\n\n1. **`index.ts`** is the HTTP entrypoint — a Hono server that serves the\n frontend and any API routes you add.\n2. **`frontend/root.tsx`** is the HTML shell — it loads Twind and stamps\n immutable asset URLs for the favicon and React entrypoint.\n3. **`frontend/index.tsx`** mounts the React app.\n4. **`frontend/components/App.tsx`** is the root layout — add new components\n alongside it.\n5. **`frontend/components/Counter.tsx`** is an example stateful component —\n replace it with your own!\n\n## Next steps\n\n- Add API routes in `index.ts`\n- Add new components in `frontend/components/`\n- Add a SQLite database — see the\n [React Hono Example](https://www.val.town/x/stevekrouse/reactHonoExample) for\n a full-stack example with database, queries, and shared types\n\nTemplate updates and upgrade paths for existing remixes: [CHANGELOG.md](/CHANGELOG.md)\n",[],[64],"3d18e2c8-0e43-4652-869f-3c1ffc084bc4","CHANGELOG.md","01a09f74-2eca-779e-bf47-3f51db77eb9f",["D",1789381586527],"# Changelog\n\n## 2026-07-30 — Immutable asset caching\n\nFrontend files are now served at version-addressed URLs\n(`/__immutable/45/frontend/index.tsx`) with\n`Cache-Control: public, max-age=31536000, immutable`, so repeat visits load the\nwhole client graph from the browser cache — roughly 3× faster (~665ms → ~157ms\nmeasured). Publishing your val bumps its version, which changes every URL, so\ncaches invalidate automatically. Old-version URLs return 404 after a publish\n(like Next.js build assets); a reload picks up the new version.\n\nWhat changed in the template:\n\n- `frontend/index.html` → [`frontend/root.tsx`](/frontend/root.tsx): the HTML\n shell is now JSX and stamps asset URLs with `immutableFileUrl()`\n- [`index.ts`](/index.ts): serves `Root()` at `/`, and one\n `app.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path))` route\n serves all frontend files\n\n### Upgrading an existing remix\n\nYour copy of this template doesn't update automatically. Two options:\n\n**Minimal (most of the benefit):** point both routes at `serveImmutableFile` —\nyour existing bare URLs redirect into versioned space, the new route serves\nthem, and the whole module graph gets cached (costs one redirect per page view):\n\n```ts\nimport { serveImmutableFile } from \"https://esm.town/v/std/utils/index.ts\";\n\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\napp.get(\"/frontend/**/*\", (c) => serveImmutableFile(c.req.path)); // was serveFile\n```\n\n**Full upgrade (also removes the redirect):** three self-contained steps —\nno other files needed. Adjust the ``, favicon, and body of `Root()` to\nmatch your app's existing `index.html`, and stamp anything else your shell\nreferences directly (images, css) with `immutableFileUrl()`.\n\n1. Create `frontend/root.tsx`:\n\n```tsx\n/** @jsxImportSource npm:hono@4/jsx */\nimport { raw } from \"npm:hono@4/html\";\nimport { immutableFileUrl } from \"https://esm.town/v/std/utils/index.ts\";\n\n// The HTML shell for the app. It is never cached, so immutableFileUrl can stamp\n// the current val version into each asset URL — the browser caches those\n// immutably, and publishing the val changes the URLs, refetching exactly once.\nexport function Root() {\n return (\n <>\n {raw(\"<!DOCTYPE html>\")}\n <html lang=\"en\">\n <head>\n <meta charSet=\"UTF-8\" />\n <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n <title>React Hono Val Town Starter\n