Cold Start Serverless Benchmarks

This repository contains cold start benchmarks for server-side JavaScript applications, executed using different JavaScript runtimes, and deployed via Docker images on AWS Lambda using AWS Lambda Web Adapter. For more information, read our blog post summary.

Benchmark Results

Results are discussed in the blog post. Raw data is available in the raw_results directory.

AWS Lambda configuration:

• Region: us-west2
• Memory: 512MB

Runtime versions:

• Deno: 1.45.2
• Bun: 1.1.19
• Node.js: 22.5.1

How To Run Benchmarks

Build Docker Images

Express app:

docker build --rm -t deno_express_app:latest -f docker/deno.dockerfile ./apps/express
docker build --rm -t node_express_app:latest -f docker/node.dockerfile ./apps/express
docker build --rm -t bun_express_app:latest -f docker/bun.dockerfile ./apps/express

Fastify app:

docker build --rm -t deno_fastify_app:latest -f docker/deno.dockerfile ./apps/fastify
docker build --rm -t node_fastify_app:latest -f docker/node.dockerfile ./apps/fastify
docker build --rm -t bun_fastify_app:latest -f docker/bun.dockerfile ./apps/fastify

Hono app:

docker build --rm -t deno_hono_app:latest -f docker/deno.dockerfile ./apps/hono
docker build --rm -t node_hono_app:latest -f docker/node.dockerfile ./apps/hono
docker build --rm -t bun_hono_app:latest -f docker/bun.dockerfile ./apps/hono

Run Benchmarks

Once the Lambda functions are created using the Docker images, you can use the run_benchmark.ts script to run the benchmark for each function. You'll need to provide the function ARN, the function invoke URL, and the number of invocations as arguments.

The script forces a cold start for each iteration, parses Init Duration from CloudWatch, and writes the results to stdout in CSV format.

e.g.

./tools/run_benchmark.ts arn:aws:lambda:us-west-2:123456789123:function:express_app_on_deno https://e6mpazwlnt5ykocyq3qcobotp40zdlpr.lambda-url.us-west-2.on.aws 25