What do HTTP status 401 and 403 mean?
PICTURE THIS: 1, 2, 2, 8
Simple meaning
401 means unauthenticated — missing or bad credentials.
WHY — HTTP instead of guessing?
Why interviewers care about HTTP:
who only read docs from people who shipped.
and tied to Backend 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:
- 1401 means unauthenticated —
missing or bad credentials.
- 2403 means authenticated but
not allowed for that resource.
- 3I never collapse both
into a generic 400 in public APIs.
- 4Give an example
One tiny concrete case you can say aloud.
- 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
401 means unauthenticated — missing or bad credentials. 403 means authenticated but not allowed for that resource.