Open-Source Observability · microsoft

ApplicationInsights-dotnet

ApplicationInsights-dotnet is Microsoft's official .NET SDK for sending telemetry and monitoring data to Azure Monitor and Application Insights. It now builds on OpenTelemetry, allowing both dedicated Azure backend integration and multi-backend telemetry delivery.

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Source: GitHub — github.com/microsoft/ApplicationInsights-dotnet

606

GitHub stars

297

Forks

Primary language

MIT

License (OSI-approved)

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

Field	Value
Repository	microsoft/ApplicationInsights-dotnet
Owner	microsoft
Primary language	C#
License	MIT — OSI-approved
Stars	606
Forks	297
Open issues	27
Latest release	v3.1.2 (2026-05-28)
Last updated	2026-07-04
Source	https://github.com/microsoft/ApplicationInsights-dotnet

What ApplicationInsights-dotnet is

A .NET SDK providing distributed tracing, logging, and observability instrumentation backed by OpenTelemetry. Offers auto-instrumentation for ASP.NET Core, Worker Services, and console apps via NuGet packages, with extensibility through standard OpenTelemetry Activity Processors and Resource Detectors.

Quickstart

Get the ApplicationInsights-dotnet source

Clone the repository and explore it locally.

terminalbash

1git clone https://github.com/microsoft/ApplicationInsights-dotnet.git2cd ApplicationInsights-dotnet3# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

Azure Monitor / Application Insights Integration

Organizations already using Azure Monitor seeking native .NET instrumentation and performance monitoring with minimal configuration overhead.

ASP.NET Core Web Applications

Auto-instrumentation of HTTP requests, dependencies, exceptions, and custom events in ASP.NET Core with the AspNetCore SDK package.

Distributed Tracing in Microservices

Multi-service .NET architectures requiring end-to-end tracing across process boundaries using OpenTelemetry standards and Azure export capabilities.

Implementation considerations

Version 3.x is a breaking change from 2.x; migration guidance is provided but requires planning and testing. Decide on 2.x (deprecation path) vs. 3.x (OpenTelemetry-based, forward) upfront.
Choose instrumentation path based on app type: ASP.NET Core SDK for web, WorkerService SDK for background jobs, base SDK for custom TelemetryClient scenarios.
Requires Azure subscription and Application Insights resource or Azure Monitor workspace configuration; no local-only fallback without external telemetry service.
OpenTelemetry extensibility means you can add non-Azure exporters, but primary design and documentation focus on Azure backend.
NLog integration available via separate NLogTarget package; ensure alignment if existing NLog infrastructure is in place.

When to avoid it — and what to weigh

Non-Azure Backend Exclusively — If your organization uses only non-Azure monitoring backends (e.g., Datadog, New Relic only), OpenTelemetry SDK or backend-specific agents may be more natural; this SDK is Azure-centric.
.NET Framework 4.x Legacy Apps Without Maintenance Appetite — Version 3.x targets modern .NET; 2.x branch exists for older Framework versions but is deprecated. Migration guidance required for legacy codebases.
Zero-Dependency Requirement — The SDK depends on Azure SDK libraries and OpenTelemetry packages; if a project forbids external dependencies, this is not suitable.
Custom Tracing Logic Without OpenTelemetry Alignment — Projects with proprietary, non-standard telemetry patterns may face friction; the SDK assumes OpenTelemetry concepts (Activities, Processors).

License & commercial use

MIT License. Permissive open-source license allowing commercial and private use, modification, and distribution with attribution.

MIT is an OSI-approved permissive license. Commercial use is explicitly allowed. No commercial restrictions; however, this is the client SDK. Using Application Insights as a backend requires a valid Azure subscription and Microsoft licensing terms for Azure Monitor services (separate from SDK license).

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

Signal	Assessment
Maintenance	Active
Documentation	Strong
License clarity	Clear
Deployment complexity	Low
DEV.co fit	Strong
Assessment confidence	High

Security considerations

SDK transmits telemetry to Azure Monitor over HTTPS. No known vulnerabilities detailed in provided data. Telemetry data (request traces, exceptions, custom events) may contain sensitive information; configure sampling and filters appropriately. Relies on Azure SDK authentication; ensure Azure credentials are managed securely. No local audit or encryption-at-rest claims are made in the provided documentation.

Alternatives to consider

OpenTelemetry SDK + Custom Exporter

If you need multi-backend flexibility or non-Azure-centric observability, use OpenTelemetry directly with alternative exporters (Jaeger, Datadog, etc.).

Serilog with Serilog.Sinks.ApplicationInsights

Lightweight logging-first approach for applications prioritizing structured logging over comprehensive instrumentation; works with Application Insights via sink.

Backend-Specific SDKs (Datadog, New Relic .NET Agent)

If your observability backend is non-Azure and you want native, optimized instrumentation without Azure dependency.

Software development agency

Build on ApplicationInsights-dotnet with DEV.co software developers

Start with the quick-start guide based on your app type (ASP.NET Core, Worker Service, or custom). Review migration guidance if upgrading from v2.x. File Azure Support requests for production issues.

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Related open-source tools

Surfaced by semantic similarity across the DEV.co open-source index.

opentelemetry-dotnet SkyAPM-dotnet ApplicationInsights-JS

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ApplicationInsights-dotnet FAQ

Can I use this SDK without Azure?

No. The SDK is designed to export to Azure Monitor / Application Insights. While OpenTelemetry allows custom exporters, the primary design targets Azure; using it elsewhere requires custom integration.

Is migration from v2.x to v3.x required?

2.x is on a separate branch and marked as deprecated; v3.x is the forward path. Migration is encouraged but not immediately mandatory. Detailed migration guidance is provided in MigrationGuidance.md.

What's the cost?

The SDK itself is free (MIT). Azure Monitor and Application Insights have separate pricing based on ingestion volume, retention, and features; consult Azure pricing for telemetry costs.

Does it work in serverless (Functions, Container Apps)?

Yes. Environment-based configuration and support for Azure Functions and Container Apps are documented; no special SDK changes needed.

Work with a software development agency

DEV.co helps companies turn open-source tools like ApplicationInsights-dotnet into production software. Our software development services cover the full lifecycle — architecture, web development, integration, and maintenance — delivered by software developers and web developers who ship. Engage our software development agency to implement or customize it for your open-source observability stack.

Ready to Add Application Insights to Your .NET App?

Start with the quick-start guide based on your app type (ASP.NET Core, Worker Service, or custom). Review migration guidance if upgrading from v2.x. File Azure Support requests for production issues.

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