Comparison questionMedium~7 minProduction / 19 of 22

Interview question

How would you think about OpenTelemetry versus the classic Application Insights SDK for a .NET API?

OpenTelemetry vs classic Application Insights SDK in a .NET API

Compares OpenTelemetry-based Azure Monitor instrumentation with older Application Insights SDK patterns for .NET services.

1Say itAnswer out loud first

2CompareCompare with Core answer

3RefineRefine with Stronger and Advanced

TL;DR

Both approaches can send useful telemetry from a .NET API to Application Insights. The classic Application Insights SDK is often straightforward for Azure-focused apps. OpenTelemetry gives a more standard instrumentation model and better portability across backends. I would choose the option that preserves request, dependency, exception, log, metric, and trace correlation with the least operational surprise for the team.

Full answer below

Practice focus

OpenTelemetry concepts, Azure Monitor integration, traces, metrics, logs, migration judgment, and instrumentation ownership.

Answer first

Answer path

Core answer first, then checkpoints toward a stronger answer.

Start
Core answer
Start here. This is the direct spoken answer to practice first.
Why this question matters
Modern observability is moving toward OpenTelemetry, but interviews care about judgment more than package names. This drill matters because the production behavior is shaped by platform configuration, code boundaries, and the operational path the team will use during a real incident.
Both approaches can send useful telemetry from a .NET API to Application Insights. The classic Application Insights SDK is often straightforward for Azure-focused apps. OpenTelemetry gives a more standard instrumentation model and better portability across backends. I would choose the option that preserves request, dependency, exception, log, metric, and trace correlation with the least operational surprise for the team.
Checkpoint
Stronger answer
Optional upgrade with examples, trade-offs, and sharper phrasing.
I would not migrate telemetry libraries just because one sounds newer. I would compare what the team relies on today: auto-collection, custom events, sampling, dashboards, alerts, dependency tracking, log correlation, and any custom processors. For OpenTelemetry I would validate exporters, semantic conventions, sampling behavior, and trace continuity in staging. The right choice is the one that keeps incidents diagnosable while matching the team's platform direction.
Finish
Advanced answer
Optional deeper angle for production judgment and nuance.
In production I would plan a telemetry migration like a release risk. I would run both paths or compare lower-environment output before switching, verify that existing alerts and dashboards still answer the same questions, and watch cardinality and ingestion cost. OpenTelemetry is attractive when multiple services or vendors are involved, but the benefit disappears if the team loses familiar Azure diagnostics during incidents. The mature answer balances standards, Azure integration, cost, and the operator experience under pressure.

Review signals

Use these to catch weak phrasing, shallow reasoning, and risky claims.

Common mistakesCandidateCommon mistakesMistakes that weaken the answer or signal shallow understanding.Open details

Details

Migrating telemetry libraries without checking dashboards and alerts.
Assuming OpenTelemetry automatically creates useful domain metrics.
Losing correlation between logs, requests, and dependencies.
Choosing based only on what is newest.

Red flagsCandidateRed flagsSignals that an interviewer may treat as risky.Open details

Details

Cannot explain traces, metrics, and logs at a basic level.
No migration plan for existing alerts.
Does not verify telemetry after deployment.
Treats observability as package installation only.

Follow-up prompts

Quick interviewer prompts inside this drill.

Follow-up questionsCandidateFollow-up questionsLikely next questions after the main answer.Open details

Details

Treat these as the next interviewer turn. Answer one out loud, then save the gap in your practice notes.

What would you compare before migrating instrumentation?
Where do custom metrics fit?
How would you verify trace correlation?
When would staying on the existing SDK be reasonable?

Continue the section

Next in Production: Correlation and Tracing

Step 20 of 22

How would you trace a request across Azure-hosted services?

Opening drill

Comparison questionMedium~7 minProduction / 19 of 22

Interview question

How would you think about OpenTelemetry versus the classic Application Insights SDK for a .NET API?

OpenTelemetry vs classic Application Insights SDK in a .NET API

Compares OpenTelemetry-based Azure Monitor instrumentation with older Application Insights SDK patterns for .NET services.

1Say itAnswer out loud first

2CompareCompare with Core answer

3RefineRefine with Stronger and Advanced

TL;DR

Full answer below

Practice focus

OpenTelemetry concepts, Azure Monitor integration, traces, metrics, logs, migration judgment, and instrumentation ownership.

Answer first

Answer path

Core answer first, then checkpoints toward a stronger answer.

Start
Core answer
Start here. This is the direct spoken answer to practice first.
Why this question matters
Modern observability is moving toward OpenTelemetry, but interviews care about judgment more than package names. This drill matters because the production behavior is shaped by platform configuration, code boundaries, and the operational path the team will use during a real incident.
Both approaches can send useful telemetry from a .NET API to Application Insights. The classic Application Insights SDK is often straightforward for Azure-focused apps. OpenTelemetry gives a more standard instrumentation model and better portability across backends. I would choose the option that preserves request, dependency, exception, log, metric, and trace correlation with the least operational surprise for the team.
Checkpoint
Stronger answer
Optional upgrade with examples, trade-offs, and sharper phrasing.
I would not migrate telemetry libraries just because one sounds newer. I would compare what the team relies on today: auto-collection, custom events, sampling, dashboards, alerts, dependency tracking, log correlation, and any custom processors. For OpenTelemetry I would validate exporters, semantic conventions, sampling behavior, and trace continuity in staging. The right choice is the one that keeps incidents diagnosable while matching the team's platform direction.
Finish
Advanced answer
Optional deeper angle for production judgment and nuance.
In production I would plan a telemetry migration like a release risk. I would run both paths or compare lower-environment output before switching, verify that existing alerts and dashboards still answer the same questions, and watch cardinality and ingestion cost. OpenTelemetry is attractive when multiple services or vendors are involved, but the benefit disappears if the team loses familiar Azure diagnostics during incidents. The mature answer balances standards, Azure integration, cost, and the operator experience under pressure.

Review signals

Use these to catch weak phrasing, shallow reasoning, and risky claims.

Common mistakesCandidateCommon mistakesMistakes that weaken the answer or signal shallow understanding.Open details

Details

Migrating telemetry libraries without checking dashboards and alerts.
Assuming OpenTelemetry automatically creates useful domain metrics.
Losing correlation between logs, requests, and dependencies.
Choosing based only on what is newest.

Red flagsCandidateRed flagsSignals that an interviewer may treat as risky.Open details

Details

Cannot explain traces, metrics, and logs at a basic level.
No migration plan for existing alerts.
Does not verify telemetry after deployment.
Treats observability as package installation only.

Follow-up prompts

Quick interviewer prompts inside this drill.

Follow-up questionsCandidateFollow-up questionsLikely next questions after the main answer.Open details

Details

Treat these as the next interviewer turn. Answer one out loud, then save the gap in your practice notes.

What would you compare before migrating instrumentation?
Where do custom metrics fit?
How would you verify trace correlation?
When would staying on the existing SDK be reasonable?

Continue the section

Next in Production: Correlation and Tracing

Step 20 of 22

How would you trace a request across Azure-hosted services?

How would you think about OpenTelemetry versus the classic Application Insights SDK for a .NET API?

Practice focus

Answer path

Why this question matters

Review signals

Follow-up prompts

Continue the section

How would you think about OpenTelemetry versus the classic Application Insights SDK for a .NET API?

Practice focus

Answer path

Why this question matters

Review signals

Follow-up prompts

Continue the section