Using Lambda Function URLs to Collect Form Submissions

April 10, 2022 • AWS, Lambda

This past week AWS announced Lambda Function URLs, public endpoints you can enable for Lambda functions to allow them to be invoked. These endpoints can be authorized with IAM, or have no authorization. These new endpoints are well suited to one-off endpoints that don’t require all the capabilities of API Gateway. These URLs are very well suited for use with webhooks. You can also use them to enable functionality on websites and blogs, for example accepting form submissions. Function URLs come with built-in CORS support, so using Function URLs for calls from websites was something AWS had in mind.

I’ve gone ahead and created a basic proof of concept showing how you can use the AWS CDK to deploy a Lambda function with a Function URL enabled to accept form submissions from a website. It should be noted that this is a very simple proof of concept, and it is not meant to be a production-ready solution. It saves your form submissions as a log message in CloudWatch instead of sending any kind of email or saving it to a database. It also has no mechanism in place to filter out spam submissions. I do have throttling in place to help limit the impact of nefarious entities invoking the function frequently to maliciously increase costs.

The repo has setup instructions to walk you through setup and deployment, take a look, and if you run into issues feel free to leave an issue.

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Proof of Concept showing how you can use AWS Lambda URLs to accept form input from a website

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Jason Butz is a software engineer and cloud architect with a strong focus on JavaScript, TypeScript, Node, and AWS. Jason has a love for open-soure software and a passion for building scalable, secure, and reliable applications.