AWS Free Tier usage limit - question

In AWS IoT Core, the billing is primarily based on the number of messages that your IoT devices send to or receive from AWS IoT. A message is a 512-byte block of data processed by AWS IoT. If you're exceeding the free tier limit, it's likely that your IoT devices are sending a lot of messages or large messages.

Here's how the charges might add up:

• The number of messages: If your devices are constantly sending messages, or if the messages are large (more than 512 bytes), the number of messages can add up quickly. Every 512 bytes count as a single message.
• Keep-alive messages: If your MQTT devices are using the MQTT protocol, they may be sending keep-alive messages to AWS IoT Core to maintain their connections. These messages also count towards your usage.
• Shadow updates: If your devices are using AWS IoT Device Shadow service, any shadow updates are also counted as messages.
• Other IoT services: If you are using other AWS IoT services, such as IoT Analytics or IoT Events, they could also contribute to your message count.

To troubleshoot:

• Check your AWS IoT Core usage: Go to the AWS IoT Core dashboard in your AWS Console. There should be a usage section that shows the number of messages sent and received.
• Check your devices: Look at the settings of your devices to see how often they are sending messages. If you can, reduce the frequency of messages or the size of messages.
• Use AWS Cost Explorer: This tool allows you to view and analyze your costs and usage. You can view your costs for specific services, and you can filter by usage type to see more details.

Remember that the AWS Free Tier allows you to send up to 250,000 messages per month free of charge.