AWS Lambda Support
AWS Lambda cold start optimization.
A cold start happens when Lambda creates a new execution environment: it fetches your code, starts the runtime and runs your initialization code. We measure where the time goes and remove it, instead of paying for warm capacity you may not need.
When You Need This
The situations where this work pays for itself.
Signs it is time
- Users notice slow first requests after quiet periods or during traffic spikes
- p99 latency is far higher than p50
- A Java, .NET or large Node.js function takes seconds to start
- You are paying for Provisioned Concurrency and want to know if it is worth it
- API Gateway timeouts appear on the first request after deployment
What you get
- A cold start report showing frequency and duration per function
- Code and packaging changes with measured results
- A recommendation on SnapStart and Provisioned Concurrency with cost impact
- Dashboards and alarms for init duration
How we do it
A clear, safe process you can follow along with.
1. Measure cold start frequency and duration
We read Init Duration from Lambda logs and traces to learn how many invocations are cold and how long they take, per function and per path.
2. Shrink and simplify the package
We bundle and tree-shake, remove unused dependencies and SDK clients, and keep layers lean.
3. Move work out of initialization
We lazy-load rarely used modules, create clients once and defer expensive setup so the init phase only does what the first request needs.
4. Choose the right runtime and memory
We compare runtimes and raise memory when it shortens init, using power tuning to check cost.
5. Apply SnapStart or Provisioned Concurrency where justified
SnapStart restores a cached snapshot for supported runtimes. Provisioned Concurrency keeps environments ready for latency-critical paths. We use them only where the numbers justify the cost.
6. Verify under real load
We load test the change and compare p95 and p99 latency before and after.
Mistakes we help you avoid
Common ways this goes wrong, and what we do instead.
Keep-warm pings
A scheduled ping warms one environment, but concurrent users still hit cold ones. Real fixes work at any concurrency.
Provisioned Concurrency everywhere
It bills continuously. We apply it only to latency-critical functions and use scheduled scaling.
Measuring averages
Cold starts live in the tail. We look at p95 and p99.
Assuming VPC is the problem
VPC networking overhead is small on current Lambda. Package size and init code are far more common causes.
Frequently Asked Questions
How long is a Lambda cold start?
It ranges from tens of milliseconds for small functions to several seconds for large Java or .NET functions. Your own logs show the exact figure.
What is Lambda SnapStart?
SnapStart takes a snapshot of an initialized function and restores it on cold start, which can cut startup time sharply for supported runtimes.
Is Provisioned Concurrency worth it?
For user-facing, latency-sensitive paths, often yes. For background work, usually not. We calculate the cost against the benefit.
Want Help With AWS Lambda cold start optimization?
Schedule an appointment. Tell us about your environment and we will outline the safest, highest-value approach.
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