Vercel

Overview

The Middleware integration with Vercel enables seamless observability for your Vercel deployments without requiring any code changes. By installing the Middleware app from the Vercel Marketplace, you gain access to comprehensive log and trace data from your applications, all centralized in the Middleware platform.

This integration leverages Vercel's Log Drain and Trace Drain capabilities to automatically forward observability data from your selected projects. The integration supports all Vercel log sources and provides automatic correlation between logs and traces through Trace ID and Span ID, enabling you to debug issues more effectively by viewing related data together.

Prerequisites

Before setting up the integration, ensure you have:

Installation

The integration process is straightforward and requires no code modifications. Follow these steps to connect your Vercel account with Middleware.

1 Access the Middleware App

Navigate to the Middleware app on the Vercel Marketplace, which is listed under the Observability category. You'll see the Middleware integration listing with installation options.

2 Select Your Vercel Team

When you click Install, you'll be prompted to select which Vercel team to connect. If you're part of multiple teams or organizations, choose the team that contains the projects you want to monitor.

3 Choose Projects to Monitor

Select the specific Vercel projects you want to integrate with Middleware. You can select multiple projects during the initial setup. These projects will have their Log Drain and Trace Drain automatically configured.

You can add or remove projects from monitoring later through Vercel's integration settings.

4 Grant Required Permissions

Review and approve the permissions that Middleware requires. These permissions enable Middleware to:

• Read project metadata for proper data visualization
• Configure Log Drain & Trace Drain settings in your Vercel account

These permissions are essential for the integration to function. Without them, Middleware cannot configure the necessary drains or access your project data.

5 Authenticate with Middleware

You'll be redirected to the Middleware login page to authenticate your account. Sign in with your Middleware credentials to complete the connection.

6 Confirmation Screen

After successful authentication and setup, you'll see a confirmation screen indicating that the integration is complete.

The integration is now active. Middleware will automatically configure both Log Drain and Trace Drain in your Vercel account from all sources and environments initially, but later you can modify sources, environments, and sampling rate from Middleware's Installation → Integration → Vercel. Data will begin flowing to your Middleware account shortly. You can verify the app installation in your Vercel's Integrations tab as well.

How the Integration Works

Once installed, the Middleware app performs the following automatic configurations:

Automatic Drain Setup

The integration automatically creates two drains in your Vercel account's drain settings:

These drains are configured with the appropriate endpoints and authentication to securely forward data to your Middleware account. You can verify these drains in your Vercel dashboard under Settings → Drains.

Supported Log Sources

Middleware supports data from all available Vercel log sources:

Environment Coverage

The integration captures data from both deployment environments:

• Production: All logs and traces from production deployments
• Preview: All logs and traces from preview deployments accessed through the generated deployment URL

This dual-environment coverage ensures you have visibility into both your live application and development previews.

Log Sampling Configuration

To help manage data volume and costs, you can configure log sampling rates directly from the Middleware platform. Sampling allows you to collect a percentage of logs rather than 100%, which is particularly useful for high-traffic applications. The sampling rate can be adjusted per project and applies to all log sources.

Logs in Middleware

After the integration is active and data begins flowing, logs from your Vercel projects will appear in Middleware's Logs module. The logs are automatically organized and enriched with metadata for easy filtering and analysis.

Log List View

The main logs view displays all log entries in a unified interface that makes it easy to scan and analyze your application's log data. The interface provides powerful filtering capabilities, allowing you to narrow down logs by any of attributes. You can search through log content, filter by severity to focus on errors or warnings, filter by source type to see only Lambda logs or only Edge logs, and filter by environment to separate production issues from preview deployments. Additionally, you can sort the log list by timestamp to see the most recent entries first, or by severity to prioritize critical issues.

Log Details Panel

When you click on any log entry, a detailed side panel opens with multiple tabs that provide comprehensive information about the log:

Traces in Middleware

Distributed traces from your Vercel deployments appear in Middleware's Traces module, providing end-to-end visibility into how requests flow through your application.

Trace List View

The traces list displays all captured traces in a unified interface. Each trace entry shows the Trace ID, service name, operation type, duration, status, start time, environment, and span count. The interface provides powerful filtering capabilities, allowing you to narrow down traces by any attributes. You can filter by service, environment, or status, and sort by duration to identify the slowest requests.

Trace Details Panel

When you open a trace from the list, a detailed side panel opens with tabs organized in two portions:

Top Portion Tabs:

Bottom Portion Tabs:

Correlation

The Vercel integration in Middleware, provides automatic correlation between logs and traces. When Vercel forwards both logs and traces from the same application, it includes Trace ID and Span ID attributes in log entries, enabling Middleware to automatically link related data.

How it works: Vercel generates a Trace ID for each request and a Span ID for each operation. These identifiers are included in log entries, allowing Middleware to correlate logs with their corresponding traces.

How to use it: Click the Trace ID link in any log entry to view the complete trace, or click "Logs" tab in a trace to see all associated logs. This enables you to navigate seamlessly between logs and traces for comprehensive debugging.

Benefits

Correlation enables several powerful debugging workflows:

• Contextual Debugging: See logs in the context of the request flow
• Root Cause Analysis: Trace errors from log entry to source
• Performance Analysis: Correlate slow operations with detailed logs
• End-to-End Visibility: Understand complete request journeys

Custom Spans

While the integration automatically collects traces from your Vercel deployments, you may want to add custom spans to instrument specific parts of your application. This is done using Vercel's official OpenTelemetry library.

npm install @vercel/otel

Limitations

Edge Runtime Traces

Functions using the Edge runtime have limitations with distributed tracing. While Edge Function logs are collected via Log Drain, custom spans generated by Edge runtime functions are not forwarded through Vercel's Trace Drain due to platform constraints. See Vercel's documentation for details.

FAQs