How would you implement idempotent POST endpoints?
PICTURE THIS: HOW TO EXPLAIN IT
IdeaASP.NET
HowWhat happens inside
Why they askShows real use
Simple meaning
Clients send an Idempotency-Key
WHY — ASP.NET instead of guessing?
Why interviewers care about ASP.NET:
This is a process
question about ASP.NET.
Panels listen for order,
trade-offs, and what you would actually do on a .NET project - not buzzwords.
Stay structured
Name the idea, why it exists, then one short example.
Close cleanly
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:
- 1Define it
Clients send an Idempotency-Key
- 2I store the key
with the response outcome.
- 3Retries return the same
result instead of duplicating work.
- 4Give an example
TTL cleanup prevents unbounded growth.
- 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:
Say this line
“Retries return the same result instead of duplicating work.”
Break into beats
Retriesreturnthesameresultinstead
Speaking order
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Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
Clients send an Idempotency-Key I store the key with the response outcome.