Think Twice Before Using Step Functions — Check the AWS Serverless Service Quotas
A majority of companies I have worked with have never run into AWS service limits for Step Functions. However, when a Fortune 1000 company came to Serverless Guru asking us to build a product that would be used for millions of customer transactions per day, I ran the numbers to see what the service limits were like in September 2020 since AWS sometimes improves limits.
AWS Service Limits, officially known as service quotas as of June 2019, can throttle a component of your app. So planning ahead and then monitoring your usage against those limits with a solution like the Limit Monitor and the Service Quotas dashboard in the AWS console is so critical for reliability, that it’s the first question on reliability in the AWS Well-Architected Tool.
TLDR. I go through a few numbers and conclude AWS Lambda (without Step Functions) is a safer bet than Step Functions or Fargate from a service limit perspective when faced with millions of unevenly distributed events per day.
Step Functions Limits, September 2020
In a scenario where nearly a dozen external systems interoperate on an event-driven basis and reliability is essential, AWS Step Functions is appealing for its ability to kick off both Lambda functions and…
