Audio Processing API Deployment on AWS Lambda

Akashdeep via Replit

Completed work

Backend Engineer

Cloud Infrastructure Architect

AWS Lambda

FFmpeg

TypeScript

Electronics

Audio Processing API in AWS Lamba using Ffmgeg

This is a audio-processing project for CDK development with TypeScript.

The cdk.json file tells the CDK Toolkit how to execute your app.

Useful commands

npm run build compile typescript to js

npm run watch watch for changes and compile

npx cdk deploy deploy this stack to your default AWS account/region

npx cdk destroy delete this stack with all the resources it includes

npx cdk diff compare deployed stack with current state

npx cdk synth emits the synthesized CloudFormation template

Routes

/transcode

    const res = await fetch('https://n2klthh2tl.execute-api.us-east-1.amazonaws.com/prod/transcode', {
        method: 'POST',
        body: JSON.stringify({
            url: "https://pub-951fa3482dca41f6bf9fa25a7953175d.r2.dev/ytaudio.webm",
            requestId: "XXXXXXXXXXXXXXXX" //optional
        }),
        headers: {
            'Content-Type': 'application/json'
        }
    })
    const data = await res.json()
    console.log(data)
    // {
    //     success: true,
    //     requestId: 'XXXXXXXXXXXXXXXX',
    //     url: 'https://audioprocessingstack-s3100bedfb-ihhtoldoybzj.s3.us-east-1.amazonaws.com/ffmpeg/temp/3f4775f7dfdada3f/f4775f7dfdada3f8.ogg'
    // }

/concat

    const res = await fetch('https://n2klthh2tl.execute-api.us-east-1.amazonaws.com/prod/concat', {
        method: 'POST',
        body: JSON.stringify({
            urls: ["https://pub-951fa3482dca41f6bf9fa25a7953175d.r2.dev/ytaudio.webm", "https://pub-951fa3482dca41f6bf9fa25a7953175d.r2.dev/ytaudio.webm"],
            requestId: "XXXXXXXXXXXXXXXX" //optional
        }),
        headers: {
            'Content-Type': 'application/json'
        }
    })
    const data = await res.json()
    console.log(data)
    // {
    //     success: true,
    //     requestId: 'XXXXXXXXXXXXXXXX',
    //     url: 'https://audioprocessingstack-s3100bedfb-ihhtoldoybzj.s3.us-east-1.amazonaws.com/ffmpeg/temp/3f4775f7dfdada3f/f4775f7dfdada3f8.ogg'
    // }

Deploy the stack on AWS

Configure IAM

Go to AWS Identity and Access Management (IAM)

Create a new policie from JSON

{
	"Version": "2012-10-17",
	"Statement": [
		{
			"Effect": "Allow",
			"Action": [
				"sts:AssumeRole"
			],
			"Resource": [
				"arn:aws:iam::*:role/cdk-*"
			]
		},
		{
            "Effect": "Allow",
            "Action": [
                "cloudformation:*"
            ],
            "Resource": "*"
        }
	]
}

Save the policie by providing a name (eg: cdk-deploy).

Create a user and as attatch permissions policie that you just created frow AWS console.

Select the newly created user and go to the Security credentials tab.

Now on the Access keys section, click on the Create access key button.

Now select use case Command Line Interface (CLI) and confirm. Click on the next button.

Click Create access key button.

Now store the Access key and Secret access key.

Configure Github Action

Go to github repo settings.

On the Security section click on Secrets and variable and then click on action.

Now click on New repository secret and two secret AWS_ACCESS_KEY_ID and AWS_SECRET_KEY and the value should be the Access key and Secret access key you got from AWS console.

(Optional) Set another secret AWS_REGION to specify the deployment region. Default region is us-east-1.

Manually trigger deployment

You can triger deployment manually by going to Action tab on github repo.

The choosing CDK Deploy action and clicking on Run workflow button.

Auto-deploy on code push

If you set up github action then whenever a new code push happen on master branch, the deployment will update automatically.

Lambda api gatway url

You can find the deployment url inside github action log. Here is a sample output:

  ✅  AudioProcessingStack

✨  Deployment time: 42.59s

Outputs:
AudioProcessingStack.gatewayEndpointDA8D204E = https://fivtqcifhd.execute-api.us-east-1.amazonaws.com/prod/
Stack ARN:
arn:aws:cloudformation:us-east-1:***:stack/AudioProcessingStack/b4cff7e0-6df8-11ef-b5ff-0ee5f6741be1

✨  Total time: 47.23s

You can see here there is a url https://fivtqcifhd.execute-api.us-east-1.amazonaws.com/prod/ inside log output. This is the lambda api gatway URL.

You can invoke lambda using this URL.

Setup custom domain

If you want to add a custom domain you can follow this guide: https://medium.com/geekculture/how-to-add-a-custom-domain-to-lambda-functions-1bc0ae639676

Configure lambda RAM size and timeout setting

You can change lambda RAM size and timeout setting inside this file: lib/audio-processing-stack.ts

These are the currentl values:

memorySize: 3008
timeout: cdk.Duration.seconds(300)

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Completed work

Posted Aug 26, 2025

Developed and deployed an audio processing API using AWS Lambda and CDK with TypeScript.

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