The Serverless Skills Gap
Most developers who say they know AWS Lambda have deployed a function or two and maybe followed a tutorial. Production serverless development, where you are responsible for cold start times, DynamoDB access patterns, IAM security, and cost optimization at scale, is a different discipline entirely.
When you hire an AWS Lambda developer for a real project, these are the skills that actually matter.
Cold Start Management
Cold starts are the first thing clients notice when a serverless app feels slow. A good Lambda developer knows the levers: keeping package sizes small with Lambda Layers, using Provisioned Concurrency on latency-sensitive endpoints, choosing the right runtime (Node.js and Python cold start faster than Java or .NET), and writing initialization code outside the handler function so it runs once per container, not once per request.
If a candidate cannot explain cold starts in concrete terms, they have not built anything that users actually complained about.
DynamoDB Design, Not Just DynamoDB Usage
Lambda and DynamoDB go together because DynamoDB scales the same way Lambda does: without connection pools, without pre-warming, without configuration. But DynamoDB's single-table design requires you to model every access pattern before you write the first line of code.
This is where most junior serverless developers fail. They treat DynamoDB like a schemaless MongoDB and end up with designs that cannot support new query requirements without a full table migration. Ask candidates to walk you through a single-table design they have built and what access patterns it supports.
IAM and Security Hygiene
Every Lambda function should have the minimum IAM permissions it needs to do its job. Not a wildcard policy, not AdministratorAccess. A developer who gives Lambda functions broad permissions is creating security debt that will eventually become a breach.
Good Lambda developers define per-function IAM roles with specific resource ARNs, use AWS Secrets Manager or Parameter Store for credentials (never environment variables for secrets), and understand how VPC configuration affects Lambda's ability to reach RDS or other private resources.
Cost Awareness
Serverless is not automatically cheap. A poorly designed Lambda architecture with synchronous fan-out, large payloads, or inefficient DynamoDB reads can cost more than a comparable EC2 setup. A skilled Lambda developer thinks about cost per request from the design phase, not after the first AWS bill arrives.
What Good Looks Like in Practice
For a personal development platform called The Silva Way, we designed and built a fully serverless backend that averaged $340 per month in AWS costs while handling unpredictable traffic spikes during product launches. The architecture used Lambda with Provisioned Concurrency on hot paths, DynamoDB with single-table design modeled around 12 access patterns, and CloudFront for media delivery.
The $22,000 project paid for itself in infrastructure savings within the first year compared to the EC2 alternative.
If you need a Lambda developer who has built and operated serverless systems in production, not just deployed tutorial functions, reach out and tell us about your project.