Hub
Application Insights
Answers to the questions the product docs skip: how to turn telemetry off locally, where the connection string goes, why data is missing, what a setting really does. Each guide shows the classic Application Insights SDK and the OpenTelemetry-based distros side by side, with Microsoft's current support dates stated plainly.
Guides
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Application Insights
Agent-based dependency tracking: what the Application Insights Agent sees and misses
How the Application Insights Agent collects SQL and HTTP dependencies on IIS, when the instrumentation engine is needed, and what still needs code.
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Application Insights
App Service auto-instrumentation vs the SDK: which one to run
What Application Insights auto-instrumentation collects on App Service, Functions, AKS and IIS, when to move to code, and why one collector per app is enough.
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Application Insights
Application Insights pricing: what you pay for, and how to cut the bill
Application Insights bills by the GB its Log Analytics workspace ingests. Current East US prices, the free allowance and retention, and what to change first.
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Application Insights
ApplicationInsights.config: do you still need it, and what replaced it
What ApplicationInsights.config controls, which apps still read it, and where its settings went in SDK 3.x and the Microsoft OpenTelemetry Distro.
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Application Insights
Application Insights for ASP.NET MVC and Web API on .NET Framework
What still works for ASP.NET MVC and Web API on .NET Framework, the HTTP modules, unhandled vs handled exceptions, trace forwarding, and the SDK 3.x upgrade.
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Application Insights
Azure Monitor alerts explained: log alerts, action groups and the alert email
What an Azure Monitor alert email means, metric vs log search alerts, action groups, a log alert over KQL step by step, what alerts cost, and how to stop noise.
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Application Insights
Azure Monitor vs Application Insights vs Log Analytics
Azure Monitor is the platform, Log Analytics the workspace and its query tool, Application Insights the APM feature. Table names, storage, and what to query.
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Application Insights
Certificate expiration monitoring with Application Insights availability tests
Use Standard availability tests to catch expiring TLS certificates, set the lifetime check and alerts, price it, and when to use TrackAvailability instead.
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Application Insights
Application Insights SDK vs the OpenTelemetry Distro: which to use and how to migrate
Classic Application Insights SDK status, SDK 3.x vs the Microsoft OpenTelemetry Distro, a concept map from 2.x, and the migration steps.
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Application Insights
Client IP address and geolocation in Application Insights
Why client_IP shows 0.0.0.0, how Application Insights fills the city and country columns, how DisableIpMasking stores real IPs, and what proxies change.
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Application Insights
Correlation in Application Insights: trace context, operation_Id and Application Map
How operation_Id and operation_ParentId map to W3C trace context, why Application Map shows one node or none, and how to correlate work across queues.
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Application Insights
Query several Application Insights resources at once with KQL
Query many apps with KQL using one workspace, workspace() and app(); find a resource from its instrumentation key; join reference data; reuse dashboards.
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Application Insights
Custom metrics in Application Insights: pre-aggregated vs log-based
GetMetric vs TrackMetric, OpenTelemetry counters and histograms, where custom metrics land, dimension limits, and how to query customMetrics correctly.
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Application Insights
Application Insights for desktop and console apps
Instrument console tools, worker services, WPF and WinForms apps with Application Insights, flush before exit, and track work without a web host.
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Application Insights
DiagnosticSource and Activity: how .NET libraries emit telemetry
DiagnosticSource vs ActivitySource in .NET, how libraries emit telemetry, listening without a vendor SDK, and what Application Insights collects.
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Application Insights
Disable Application Insights in development and debug builds
Stop local runs from sending telemetry, for the classic Application Insights SDK, SDK 3.x and the OpenTelemetry distros, in .NET and Node.js.
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Application Insights
Enable Application Insights Live Metrics from code
Turn Live Metrics on or off in code for the classic SDK, SDK 3.x and the OpenTelemetry Distro, secure it with Entra ID, and fix an empty Live Metrics pane.
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Application Insights
The Application Insights JavaScript snippet explained
What the JavaScript SDK Loader Script does, loader vs npm, the connection string in the browser, linking page views to server requests, and cookie consent.
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Application Insights
Application Insights logging: ILogger, Serilog, severity levels and the traces table
How ILogger and Serilog logs reach the Application Insights traces table, which levels are sent by default, severity mapping, scopes, and what debug logs cost.
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Application Insights
No data in Application Insights? SDK self-diagnostics and a checklist
A checklist for missing Application Insights telemetry, and how to turn on self-diagnostics in the classic SDK, SDK 3.x, OpenTelemetry and Java.
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Application Insights
Performance counters and runtime metrics in non-web apps
Why CPU and memory counters go missing in console apps, services and containers, and how to collect them with the classic SDK, SDK 3.x and OpenTelemetry.
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Application Insights
How Application Insights names requests, and how to change operation_Name
Where request names and operation_Name come from in the classic SDK and OpenTelemetry, why 404s and static files behave oddly, and how to rename requests.
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Application Insights
Application Insights sampling: the types, the defaults, and why it beats filtering
Adaptive, fixed-rate, rate-limited and ingestion sampling in Application Insights, each SDK's default, counting with itemCount, and why filters skew metrics.
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Application Insights
Send telemetry to Application Insights with one request: curl, PowerShell, OTLP
Post a custom event or metric to Application Insights with curl or PowerShell, read the response, validate the JSON, and when to use OTLP or an SDK instead.
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Application Insights
Set the Application Insights connection string programmatically
Where the Application Insights connection string goes in code for the OpenTelemetry distros and SDK 3.x, and which setting wins.
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Application Insights
Telemetry channels: in-memory vs server channel, and the OpenTelemetry exporter
How Application Insights buffers and sends telemetry, InMemoryChannel vs ServerTelemetryChannel, Flush at shutdown, proxies, and the exporter's offline storage.
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Application Insights
Telemetry initializers in Application Insights, and their OpenTelemetry equivalents
What ITelemetryInitializer and ITelemetryProcessor do, how to add custom dimensions and role names, and the OpenTelemetry processors that replace them.
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Application Insights
Tracking users and sessions in API apps
Why user_Id and session_Id are empty for APIs, how to set them from claims and headers in the classic SDK and OpenTelemetry, and what to keep out of them.
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Application Insights
Attach version and build information to Application Insights telemetry
Set application_Version from your build in the classic SDK, SDK 3.x and OpenTelemetry (service.version), mark deployments, and compare versions in KQL.
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Application Insights
What is Application Insights? A 2026 explainer
Application Insights is the APM feature of Azure Monitor. What it collects, where the data lives, how apps send it in 2026, what it costs and when to skip it.
Queries for these tables
KQL library →-
Apdex-style satisfaction score per operation
requests latency
Returns: One row per operation with its request count, the satisfied, tolerating and frustrated counts against the target, and a 0-to-1 score, worst first.
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Availability results by test and location
availabilityResults availability
Returns: One row per availability test and test location with the number of runs, the failed runs, the availability percentage and the p95 test duration in milliseconds, worst first.
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Availability test failures with their messages
availabilityResults availability
Returns: Up to 100 failed availability test runs from the last 24 hours, newest first, each with the test name, location, duration in milliseconds, failure message and operation_Id.
Tools
- Sampling and ingestion cost calculator
Turn events per day and item size into GB per month, a sampling percentage for a daily cap, and a cost at your price per GB.
- KQL query builder
Pick a table, a time range, percentiles and a grouping, and copy a ready query with a plain-English line of what it returns.