Does Fastify Work With AWS?
Fastify integrates seamlessly with AWS services as a lightweight Node.js framework for building serverless APIs, REST services, and Lambda-backed applications.
Quick Facts
How Fastify Works With AWS
Fastify works excellently on AWS through multiple deployment patterns. The most common approach is AWS Lambda with API Gateway, where Fastify handles request routing with minimal overhead—critical since Lambda charges per 100ms. You can use the `@fastify/aws-lambda` plugin to wrap your Fastify app for Lambda execution, handling cold starts efficiently. Alternatively, deploy Fastify on EC2, ECS, or App Runner for always-on servers. The framework's low memory footprint and fast startup time make it ideal for containerized workloads. AWS SDK v3 integrates naturally with Fastify—install `@aws-sdk/client-*` packages and use them in your route handlers. For databases, Fastify pairs well with DynamoDB, RDS, and Aurora. The developer experience is straightforward: write your Fastify app normally, then adapt the entry point for your chosen AWS service. The main architectural consideration is cold start optimization on Lambda—Fastify's minimal startup time helps, but you'll want to use Lambda layers for dependencies and consider provisioned concurrency for critical endpoints.
Best Use Cases
Fastify on AWS Lambda
npm install fastify @fastify/aws-lambda @aws-sdk/client-dynamodbimport Fastify from 'fastify';
import awsLambdaFastify from '@fastify/aws-lambda';
import { DynamoDBClient } from '@aws-sdk/client-dynamodb';
const fastify = Fastify();
const dynamodb = new DynamoDBClient({ region: 'us-east-1' });
fastify.get('/items/:id', async (request, reply) => {
const { id } = request.params as { id: string };
try {
// Query DynamoDB
const result = await dynamodb.send(
new GetCommand({ TableName: 'Items', Key: { id: { S: id } } })
);
return reply.code(200).send(result.Item);
} catch (error) {
return reply.code(500).send({ error: 'Failed to fetch item' });
}
});
export const handler = awsLambdaFastify(fastify);Known Issues & Gotchas
Cold start latency on Lambda can add 1-3 seconds on first invocation
Fix: Use Lambda layers to bundle dependencies, enable provisioned concurrency for critical APIs, or switch to always-on compute like App Runner
API Gateway has a 29-second timeout; long-running operations fail silently
Fix: Offload heavy work to async queues (SQS, Lambda), use Step Functions for orchestration, or switch to ALB/NLB with configurable timeouts
AWS SDK v3 adds ~8MB to bundle size, impacting Lambda cold starts
Fix: Use Lambda layers for SDK, tree-shake unused services, or use SDK v2 if stuck on legacy
CORS headers must be configured in both Fastify and API Gateway, causing duplication issues
Fix: Handle CORS only in Fastify via `@fastify/cors`, disable CORS in API Gateway to avoid double-headers
Alternatives
- •Express.js with serverless-express plugin (more mature but heavier)
- •AWS Lambda Powertools + native handler (minimal abstraction, more control)
- •API Gateway + Python (Chalice or SAM) for different language preference
Resources
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