Vercel Observability

Overview

Configure comprehensive observability for Vercel deployments using built-in analytics, runtime logs, log drains to external providers, OpenTelemetry integration, and custom instrumentation. Covers the full observability stack from function-level metrics to end-user experience monitoring.

Prerequisites

Vercel Pro or Enterprise plan (for log drains and extended retention)
External logging provider (Datadog, Axiom, Sentry) — optional
OpenTelemetry SDK — optional

Instructions

Step 1: Enable Vercel Analytics

In the Vercel dashboard:

Go to Analytics tab
Enable Web Analytics (Core Web Vitals, page views)
Enable Speed Insights (real user performance data)

// For Next.js — add the analytics component
// src/app/layout.tsx
import { Analytics } from '@vercel/analytics/react';
import { SpeedInsights } from '@vercel/speed-insights/next';

export default function RootLayout({ children }) {
  return (
    <html>
      <body>
        {children}
        <Analytics />
        <SpeedInsights />
      </body>
    </html>
  );
}

Install: npm install @vercel/analytics @vercel/speed-insights

Step 2: Runtime Logs

# View runtime logs via CLI
vercel logs https://my-app.vercel.app --follow

# Filter by level
vercel logs https://my-app.vercel.app --level=error

# View logs via API
curl -s -H "Authorization: Bearer $VERCEL_TOKEN" \
  "https://api.vercel.com/v2/deployments/dpl_xxx/events?limit=50&direction=backward" \
  | jq '.[] | {timestamp: .created, level: .level, message: .text}'

Runtime logs include:

Function invocation start/end with duration
console.log/warn/error output from functions
Edge Middleware execution logs
HTTP request/response metadata

Step 3: Structured Logging in Functions

// lib/logger.ts — structured JSON logging
interface LogEntry {
  level: 'info' | 'warn' | 'error';
  message: string;
  requestId?: string;
  duration?: number;
  [key: string]: unknown;
}

export function log(entry: LogEntry): void {
  // Vercel captures console output as runtime logs
  const output = JSON.stringify({
    ...entry,
    timestamp: new Date().toISOString(),
    region: process.env.VERCEL_REGION,
    env: process.env.VERCEL_ENV,
  });

  switch (entry.level) {
    case 'error': console.error(output); break;
    case 'warn': console.warn(output); break;
    default: console.log(output);
  }
}

// Usage in API route:
export async function GET(request: Request) {
  const requestId = crypto.randomUUID();
  const start = Date.now();

  try {
    const data = await fetchData();
    log({ level: 'info', message: 'Fetched data', requestId, duration: Date.now() - start });
    return Response.json(data);
  } catch (error) {
    log({ level: 'error', message: 'Data fetch failed', requestId, error: String(error) });
    return Response.json({ error: 'Internal error', requestId }, { status: 500 });
  }
}

Step 4: Log Drains (External Providers)

Configure log drains to send all Vercel logs to your logging provider:

In dashboard: Settings > Log Drains > Add

Supported providers:

Provider	Type	Setup
Datadog	HTTP	API key + site URL
Axiom	HTTP	API token + dataset
Sentry	HTTP	DSN
Custom	HTTP/NDJSON	Any HTTPS endpoint
Grafana Loki	HTTP	Push URL + auth

Log drain delivers:

Runtime logs: function invocations, console output
Build logs: build step output, warnings, errors
Static logs: CDN access logs (edge)
Firewall logs: WAF events

# Create a log drain via API
curl -X POST "https://api.vercel.com/v2/integrations/log-drains" \
  -H "Authorization: Bearer $VERCEL_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "my-datadog-drain",
    "type": "json",
    "url": "https://http-intake.logs.datadoghq.com/api/v2/logs",
    "headers": {"DD-API-KEY": "your-datadog-api-key"},
    "sources": ["lambda", "edge", "build", "static"]
  }'

Step 5: OpenTelemetry Integration

// instrumentation.ts (Next.js 13.4+)
import { NodeSDK } from '@opentelemetry/sdk-node';
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-http';
import { getNodeAutoInstrumentations } from '@opentelemetry/auto-instrumentations-node';

export function register() {
  const sdk = new NodeSDK({
    traceExporter: new OTLPTraceExporter({
      url: process.env.OTEL_EXPORTER_OTLP_ENDPOINT,
    }),
    instrumentations: [getNodeAutoInstrumentations()],
    serviceName: 'my-vercel-app',
  });
  sdk.start();
}

// next.config.js
module.exports = {
  experimental: {
    instrumentationHook: true,
  },
};

Step 6: Error Tracking with Sentry

npx @sentry/wizard@latest -i nextjs

// sentry.client.config.ts
import * as Sentry from '@sentry/nextjs';

Sentry.init({
  dsn: process.env.NEXT_PUBLIC_SENTRY_DSN,
  environment: process.env.VERCEL_ENV,
  release: process.env.VERCEL_GIT_COMMIT_SHA,
  tracesSampleRate: process.env.VERCEL_ENV === 'production' ? 0.1 : 1.0,
});

Monitoring Dashboard Checklist

Metric	Source	Alert Threshold
Error rate	Runtime logs	> 1% of requests
P95 function latency	Vercel Analytics	> 2s
Cold start frequency	Runtime logs	> 20% of invocations
Build success rate	Build logs	Any failure
Core Web Vitals (LCP)	Speed Insights	> 2.5s
Edge cache hit rate	Static logs	< 80%

Output

Vercel Analytics and Speed Insights enabled
Structured JSON logging in all functions
Log drains configured to external provider
Error tracking with Sentry or equivalent
OpenTelemetry tracing for distributed systems

Error Handling

Error	Cause	Solution
Logs missing	Log retention expired (1hr free, 30d with Plus)	Enable log drains for persistence
Analytics not tracking	Missing `<Analytics />` component	Add to root layout
Log drain not receiving	Wrong URL or auth headers	Test the endpoint directly with curl
Sentry not capturing errors	DSN not set in production env	Add `NEXT_PUBLIC_SENTRY_DSN` to Production scope
OTEL traces missing	instrumentation.ts not loaded	Enable `instrumentationHook` in next.config.js

Resources

Next Steps

For incident response, see vercel-incident-runbook.