What is provisioned concurrency, and when should you use it?

Difficulty: 6/10

provisioned concurrency, cold start mitigation, cost trade‑offs

Provisioned Concurrency in AWS Lambda

Provisioned Concurrency in AWS Lambda is a feature that keeps a pre-defined number of Lambda instances initialized and ready to respond immediately. Unlike standard Lambda invocations where a cold start may occur, provisioned concurrency eliminates cold starts by always keeping the environment warm and pre-initialized. This is especially useful for latency-sensitive applications where response time is critical.

When to Use Provisioned Concurrency

1
For APIs or web applications requiring consistently low latency
2
During traffic spikes or predictable high-traffic periods
3
For scheduled tasks that must start immediately without cold start delays
4
In high-performance backend processing where startup time impacts user experience

How It Works

1
You define the number of pre-warmed instances for a specific version or alias of your Lambda function
2
AWS continuously keeps that number of instances initialized
3
Requests are routed to these pre-initialized instances, avoiding cold starts

Set Up Provisioned Concurrency Using AWS CLI

Scenario Questions

0-2 years experience

2-5 years experience

1During a recent release you enabled provisioned concurrency for a payment‑processing Lambda, but you saw higher costs without noticeable latency improvement. What could be causing this and how would you troubleshoot?

Follow-up Questions