High HTTP Question 190 of 226

What is backpressure on an HTTP API, and how do you apply it?

Java Specialist · Speak this in 60–90 seconds · Faridabad & Delhi NCR

PICTURE THIS: 1, 2, 2, 8

Mean3.25average

Median2middle

Mode2most often

Simple meaning

Backpressure means slowing or rejecting work when downstream cannot keep up, instead of queueing until you OOM.

WHY — HTTP instead of guessing?

Why interviewers care about HTTP:

HTTP questions separate people

who only read docs from people who shipped.

Keep it short, concrete,

and tied to Backend work.

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:

1
Backpressure means slowing or
rejecting work when downstream cannot keep up, instead of queueing until you OOM.
2
Return 429 or 503,
shrink the servlet pool, and use bounded queues on executors.
3
In reactive WebFlux, demand
signals through the pipeline
4
in servlet stacks you
must bound threads yourself.
5
Common mistake
What juniors usually get wrong.
6
Close
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

“Return 429 or 503, shrink the servlet pool, and use bounded queues on executors.”

Break into beats

Return429or503shrinkthe

Speaking order

2987408337471632900

Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.

Key takeaway

Backpressure means slowing or rejecting work when downstream cannot keep up, instead of queueing until you OOM. Return 429 or 503, shrink the servlet pool, and use bounded queues on executors.