Begin by familiarizing yourself with the ChartMogul API documentation. Identify the data endpoints you need to access, such as customers, subscriptions, invoices, etc. Understand the data structure and the necessary authentication methods (usually API keys).

Ensure you have access to an AWS account and have set up the AWS CLI and AWS SDKs on your local machine. Create an IAM user with permissions to interact with DynamoDB. Securely store the access key and secret access key for authentication.

Using the AWS Management Console or AWS CLI, create a DynamoDB table where the ChartMogul data will be stored. Define the primary key structure based on the data you plan to migrate (e.g., customer ID, subscription ID).

Develop a script in a programming language like Python, Node.js, or Java to interact with the ChartMogul API. Use HTTP requests to fetch data from the required endpoints. Handle pagination if necessary, since APIs often return data in chunks.

Convert the fetched data into a format compatible with DynamoDB. This may involve restructuring JSON objects, converting data types, and ensuring the data fits within DynamoDB's attribute constraints (e.g., no nested attributes).

Use the AWS SDK for your chosen programming language to insert data into the DynamoDB table. Implement batch operations to efficiently handle large datasets, keeping in mind DynamoDB's throughput limits to avoid throttling.

After the initial data migration, verify that the data in DynamoDB matches the data in ChartMogul. Implement logging within your script to track the migration process and any errors encountered. Set up CloudWatch alarms or other monitoring tools to ensure ongoing data integrity and performance.

By following these steps, you can migrate data from ChartMogul to DynamoDB using API calls and AWS SDKs without relying on third-party connectors or integrations.