npx skills add neondatabase/agent-skills --skill neon

// neon.ts
import { defineConfig } from "@neon/config/v1";

export default defineConfig({
  preview: {
    functions: {
      todos: {
        // slug: ^[a-z0-9]{1,20}$ — lowercase letters/digits, no hyphens
        name: "todo api", // display label only
        source: "src/index.ts", // entry file, relative to neon.ts
      },
    },
  },
});

// src/index.ts
import { Hono } from "hono";
import { drizzle } from "drizzle-orm/node-postgres";
import { Pool } from "pg";
import { parseEnv } from "@neon/env";
import config from "../neon";
import { todos } from "./db/schema";

const env = parseEnv(config);
const pool = new Pool({ connectionString: env.postgres.databaseUrl, max: 5 });
const db = drizzle(pool);

const app = new Hono();
app.get("/", (c) => c.text("Neon + Hono + Drizzle"));
app.post("/todos", async (c) => {
  const { text } = await c.req.json<{ text: string }>();
  const [row] = await db.insert(todos).values({ text }).returning();
  return c.json(row, 201);
});
app.get("/todos", async (c) => c.json(await db.select().from(todos)));

export default app;

const { postgres } = parseEnv(config, ["DATABASE_URL"]); // not the unpooled URL, auth, etc.
const pool = new Pool({ connectionString: postgres.databaseUrl, max: 5 });

neon dev      # serves every function in neon.ts with hot reload; injects DATABASE_URL & friends
neon deploy   # bundles with esbuild, uploads, and applies neon.ts to the linked branch

neon config status   # print the branch's live config (deployed functions)
neon config plan     # dry-run diff of what apply would change
neon config apply    # bundle + deploy the declared functions  (neon deploy is an alias)

export default defineConfig({
  preview: {
    functions: { todos: { name: "todo api", source: "src/index.ts" } },
  },
  branch: (branch) => ({
    preview: { functions: { todos: { runtime: "nodejs24" } } },
  }),
});

functions: {
  todos: {
    name: "todo api",
    source: "src/index.ts",
    env: { RESEND_API_KEY: process.env.RESEND_API_KEY! },
  },
}

import { drizzle } from "drizzle-orm/node-postgres";
import { Pool } from "pg";

// Created once per isolate; reused by every request that isolate handles.
const pool = new Pool({ connectionString: process.env.DATABASE_URL, max: 5 });
const db = drizzle(pool);

Browser ──(Authorization: Bearer <JWT>)──▶  Neon Function (agent)   ✅ no host timeout
Browser ──▶ your app backend ──▶ Neon Function                       ❌ host cuts the stream

// src/index.ts — verify the caller before doing any work
import { createRemoteJWKSet, jwtVerify } from "jose";

const jwks = createRemoteJWKSet(new URL(`${process.env.AUTH_BASE_URL}/api/auth/jwks`));

export default {
  async fetch(request: Request) {
    if (request.method === "OPTIONS") return new Response(null, { status: 204, headers: cors(request) });

    const auth = request.headers.get("authorization");
    if (!auth?.toLowerCase().startsWith("bearer ")) {
      return new Response("Unauthorized", { status: 401, headers: cors(request) });
    }
    try {
      const { payload } = await jwtVerify(auth.slice(7), jwks, {
        issuer: process.env.AUTH_BASE_URL,
        audience: process.env.AUTH_BASE_URL,
      });
      const userId = payload.sub; // scope the agent to this user
      // ... run the agent, return result.toUIMessageStreamResponse({ headers: cors(request) })
    } catch {
      return new Response("Unauthorized", { status: 401, headers: cors(request) });
    }
  },
};

import { upgradeWebSocket } from "@neon/functions";

export default {
  async fetch(req: Request): Promise<Response> {
    if (req.headers.get("upgrade")?.toLowerCase() !== "websocket") {
      return new Response("expected a websocket upgrade", { status: 426 });
    }

    const { socket, response } = upgradeWebSocket(req);
    socket.addEventListener("message", (event) => socket.send(event.data));
    return response;
  },
};

// src/index.ts
import { upgradeWebSocket } from "@neon/functions";

const clients = new Set<WebSocket>();

export default {
  async fetch(request: Request): Promise<Response> {
    if (request.headers.get("upgrade")?.toLowerCase() !== "websocket") {
      return new Response("WebSocket endpoint — connect with ?token=<jwt>");
    }

    const url = new URL(request.url);
    const identity = await verifyToken(url.searchParams.get("token"));
    if (!identity) return new Response("unauthorized", { status: 401 });

    const { socket, response } = upgradeWebSocket(request);
    clients.add(socket);
    socket.addEventListener("close", () => clients.delete(socket));
    socket.addEventListener("message", (event) => {
      if (typeof event.data !== "string") return;
      persist(identity.id, event.data); // fan out to every isolate — see below
    });
    return response;
  },
};

// src/index.ts
import { Hono } from "hono";
import { upgradeWebSocket } from "@neon/functions";

const app = new Hono();

app.get("/", (c) => c.text("ok"));

app.get("/ws", async (c) => {
  const identity = await verifyToken(c.req.query("token"));
  if (!identity) return c.text("Unauthorized", 401);

  const { socket, response } = upgradeWebSocket(c.req.raw);
  socket.addEventListener("open", () => socket.send("welcome"));
  socket.addEventListener("message", (event) => socket.send(`echo: ${event.data}`));
  return response;
});

export default { fetch: (request: Request) => app.fetch(request) };

const HEARTBEAT_MS = 25_000; // comfortably under proxy idle timeouts

const beat = setInterval(() => {
  for (const socket of clients) {
    if (socket.readyState === socket.OPEN) socket.send('{"type":"ping"}');
  }
}, HEARTBEAT_MS);
beat.unref?.();

let lastId = 0;
const poller = setInterval(async () => {
  if (clients.size === 0) return; // no clients here → no query → compute can scale to zero
  const { rows } = await pool.query(
    "SELECT id, payload FROM events WHERE id > $1 ORDER BY id",
    [lastId],
  );
  for (const { id, payload } of rows) {
    lastId = id;
    for (const socket of clients) {
      if (socket.readyState === socket.OPEN) socket.send(payload);
    }
  }
}, 1000);
poller.unref?.();

import { Pool, Client } from "pg";

const pool = new Pool({ connectionString: process.env.DATABASE_URL, max: 5 });
const CHANNEL = "chat_events";

// One dedicated DIRECT connection per isolate, just to receive events.
// Use DATABASE_URL_UNPOOLED — LISTEN needs a real session, not a pooled one.
const listener = new Client({ connectionString: process.env.DATABASE_URL_UNPOOLED });
listener.connect().then(() => listener.query(`LISTEN ${CHANNEL}`));
listener.on("notification", (msg) => {
  if (!msg.payload) return;
  for (const socket of clients) {
    if (socket.readyState === socket.OPEN) socket.send(msg.payload);
  }
});

// Broadcast by NOTIFYing through the pool — every isolate's listener fires.
function broadcast(event: unknown) {
  return pool.query("SELECT pg_notify($1, $2)", [CHANNEL, JSON.stringify(event)]);
}

let closed = false, retry = 0, timer: ReturnType<typeof setTimeout>;

async function connect() {
  if (closed) return;
  const token = await getToken(); // re-mint each attempt; short-lived
  const ws = new WebSocket(`${WS_URL}?token=${encodeURIComponent(token)}`);
  ws.onopen = () => { retry = 0; };          // reset backoff on success
  ws.onmessage = (e) => { /* apply the event */ };
  ws.onclose = () => {
    if (!closed) timer = setTimeout(connect, Math.min(1000 * 2 ** retry++, 15000));
  };
  ws.onerror = () => ws.close();             // let onclose drive the retry
}
connect();

// src/index.ts — minimal SSE endpoint
const encoder = new TextEncoder();
export default {
  fetch: () =>
    new Response(
      new ReadableStream<Uint8Array>({
        start(controller) {
          controller.enqueue(encoder.encode("data: hello\n\n"));
          const t = setInterval(() => controller.enqueue(encoder.encode(": ping\n\n")), 25_000);
          return () => clearInterval(t); // fires when the client disconnects
        },
      }),
      { headers: { "Content-Type": "text/event-stream", "Cache-Control": "no-cache, no-transform" } },
    ),
};

const transport = new StreamableHTTPTransport();
app.all("/mcp", async (c) => {
  if (!mcpServer.isConnected()) await mcpServer.connect(transport);
  return transport.handleRequest(c);
});

neon logs query --branch production --source function --since 1h