What are the DI lifetimes in ASP.NET Core?
PICTURE THIS: A REST CALL
Simple meaning
Transient is a new instance every resolve.
WHY — DI instead of guessing?
Why interviewers care about DI:
who only read docs from people who shipped.
and tied to .NET work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1Transient is a new
instance every resolve.
- 2Scoped lives for one
HTTP request.
- 3How it works
Singleton lives for the app.
- 4I never inject a
scoped DbContext into a singleton because it becomes a captured, stale, or concurrent context.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
Transient is a new instance every resolve. Scoped lives for one HTTP request.