← All PostsJul 11, 2026

Push notifications from Next.js

Next.js on Vercel runs serverless. Un-awaited promises can be dropped when the response ends. Here’s how to send notifications correctly from App Router.

In an API route (Route Handler)

Use waitUntil from @vercel/functions:

import { waitUntil } from "@vercel/functions"
import fyi from "trigger.fyi"
import { NextResponse } from "next/server"
 
export async function POST(req: Request) {
  const user = await createUser(await req.json())
 
  const response = NextResponse.json(user)
 
  waitUntil(fyi("New signup", { body: user.email, plan: user.plan }))
 
  return response
}

Or just await it — fyi() never throws, completes in one edge roundtrip:

export async function POST(req: Request) {
  const user = await createUser(await req.json())
  await fyi("New signup", { body: user.email })
  return NextResponse.json(user)
}

In a Server Action

Server Actions run on the server. await works directly:

"use server"
 
import fyi from "trigger.fyi"
 
export async function signupAction(formData: FormData) {
  const user = await createUser({
    email: formData.get("email") as string,
    plan: formData.get("plan") as string,
  })
 
  await fyi("New signup", { body: user.email, plan: user.plan })
 
  return { success: true, userId: user.id }
}

The action waits for the notification before returning. fyi() adds ~100ms — acceptable for form submissions.

In a Stripe webhook handler

import { NextResponse } from "next/server"
import { waitUntil } from "@vercel/functions"
import Stripe from "stripe"
import fyi from "trigger.fyi"
 
const stripe = new Stripe(process.env.STRIPE_SECRET_KEY!)
 
export async function POST(req: Request) {
  const body = await req.text()
  const sig = req.headers.get("stripe-signature")!
 
  let event: Stripe.Event
  try {
    event = stripe.webhooks.constructEvent(body, sig, process.env.STRIPE_WEBHOOK_SECRET!)
  } catch {
    return NextResponse.json({ error: "Bad signature" }, { status: 400 })
  }
 
  const response = NextResponse.json({ received: true })
 
  if (event.type === "payment_intent.succeeded") {
    const pi = event.data.object as Stripe.PaymentIntent
    const amount = (pi.amount / 100).toFixed(2)
 
    waitUntil(fyi(`$${amount} payment`, { body: pi.receipt_email ?? undefined }))
  }
 
  return response
}

In a background route (after response)

For routes that process slow work:

import { waitUntil } from "@vercel/functions"
import fyi from "trigger.fyi"
 
export async function POST(req: Request) {
  const job = await req.json()
 
  // Return immediately — process in background
  const response = new Response("Accepted", { status: 202 })
 
  waitUntil(
    processJob(job).then((result) =>
      fyi("Job complete", {
        body: `${result.count} items · ${result.elapsed}s`,
        jobId: job.id,
      })
    )
  )
 
  return response
}

Environment variable

# .env.local
TRIGGER_FYI_SECRET_KEY=your_key_here

The SDK reads it at call time — no module-level initialization. Works in Edge Runtime, Node.js Runtime, and Server Actions.

Edge Runtime

fyi() uses fetch under the hood and works in Edge Runtime:

export const runtime = "edge"
 
export async function POST(req: Request) {
  const data = await req.json()
  await fyi("Edge function called", { body: data.id })
  return new Response("OK")
}

Middleware

For lightweight notifications from middleware:

import { NextResponse } from "next/server"
import type { NextRequest } from "next/server"
 
export function middleware(req: NextRequest) {
  // Don't await in middleware — use waitUntil via context
  // Or use a fire-and-forget fetch directly
  fetch(`https://trigger.fyi/${process.env.TRIGGER_FYI_SECRET_KEY}`, {
    method: "POST",
    body: `Middleware: ${req.nextUrl.pathname}`,
  }).catch(() => {}) // swallow errors
 
  return NextResponse.next()
}

Setup

npx trigger.fyi

Generates a key, subscribes your device. Done.

#In an API route (Route Handler)

#In a Server Action

#In a Stripe webhook handler

#In a background route (after response)

#Environment variable

#Edge Runtime

#Middleware

#Setup