AWS IoT Core is often the first stop for teams beginning their IoT journey. It is easy to adopt, tightly integrated with the AWS ecosystem, and ideal for early prototypes or small deployments. For proof-of-concept work or low-frequency data, the pricing feels simple and predictable.

The challenge is what happens when those deployments expand, device behavior becomes more active, and millions or billions of messages begin flowing through the system. Many teams reach this stage and discover that AWS IoT Core’s metered pricing grows far faster than the workload itself, creating a cost wall that forces a re-evaluation of their architecture.

This article explains why AWS IoT Core becomes expensive at scale, how EMQX uses a more predictable capacity model, and why many organizations see 60 to 80% lower monthly IoT spending after making the switch.

Why AWS IoT Core Costs Rise Faster Than Expected

AWS IoT Core charges for every interaction with the broker. The more active your devices are, the more expensive the service becomes. Four billing dimensions contribute to this pattern: message metering, rules engine activity, connectivity minutes, and device shadow operations.

1. Message metering and the 5 KB minimum

AWS bills messages in 5 KB chunks. Even if a device sends a lightweight binary payload that is only 40 or 50 bytes, it is still charged as 5,000 bytes. Larger payloads are rounded up again in 5 KB increments. Messaging costs apply to both ingress and egress, which means bi-directional communication can double the bill. For high-frequency telemetry, this becomes the dominant cost driver.

2. Rules engine activity adds another 30%

Most IoT architectures route every message to storage, analytics, or downstream applications. With AWS, every rule trigger and every action creates an additional charge. A basic pattern like “one message triggers one rule and one action” adds roughly 30% on top of the messaging cost. More complex logic increases this further.

3. Connectivity minutes create a baseline cost

To support low-latency control and immediate downlink updates, devices often stay connected around the clock. AWS charges for connection time in one-minute increments. While the per-minute price is low, it creates a floor cost that grows with deployment size even when traffic is minimal.

4. Device shadow operations are the most expensive meter

AWS charges separately for reading and writing a device’s shadow state. In workloads where devices frequently report their status, shadow operations can outpace messaging costs. A misconfigured firmware update that sends too many shadow writes can produce a significant and unexpected bill.

How It All Adds Up

These four billing dimensions scale directly with device activity. As deployments grow more chatty, AWS IoT Core’s costs compound instead of leveling off.

How EMQX Approaches the Same Problem

EMQX takes a capacity-based approach. Instead of charging for every message or rule, EMQX Dedicated Flex bills for the resources needed to handle the workload. This model separates concurrency (sessions) from throughput (TPS), allowing teams to match their infrastructure to their actual device behavior.

1. Ingress is always free

EMQX does not charge for incoming messages. Whether a system sends one million or one billion messages, there is no metering of inbound traffic. This eliminates the cost pressure associated with high-frequency telemetry.

2. Decoupled sessions and TPS allow right-sizing

Sessions correspond to RAM. TPS corresponds to CPU. By separating these two factors, EMQX lets teams select the exact combination that matches their workload. A large number of always-connected devices with low message throughput can choose a high-session, low-TPS configuration. A small number of sensors pushing thousands of messages per second can choose a low-session, high-TPS configuration. This avoids the blended rate AWS applies to all workloads.

3. Rule engine usage is included in the base fee

Routing, filtering, transforming, and forwarding data is part of the core service. EMQX Dedicated Flex does not charge per rule or per action. This allows teams to use rich data processing without worrying about cost spikes.

4. Traffic charges can be minimized through VPC peering

Outbound traffic routed through VPC peering or private links is not billed as public internet egress. Most production environments use private networking, which reduces traffic fees to nearly zero.

A Real Example: Reducing Spending by More Than 80%

To illustrate the difference between the two pricing models, consider a realistic industrial scenario. This example is adapted from internal load modeling and pricing analysis.

Workload profile

• 1,000 industrial sensors
• 10 messages per second per device
• Total throughput of 10,000 messages per second
• Payload size roughly 0.5 KB per message

This pattern is common in vibration monitoring, equipment diagnostics, and high-resolution telemetry.

AWS IoT Core monthly cost

• Messaging: approximately 26.28 billion messages Cost: about 26,280 dollars per month
• Rules engine triggers and actions Cost: about 7,884 dollars per month
• Connectivity: included but minimal
• Total AWS IoT Core cost: about 34,167 dollars per month

EMQX Dedicated Flex monthly cost

• Required capacity: 10,000 TPS
• Rate for this tier: about 8.24 dollars per hour
• Monthly base fee: about 6,015 dollars
• Ingress is free
• Egress over VPC peering is effectively free
• Total EMQX cost: about 6,015 dollars per month

Cost Comparison Table

Cost Component	AWS IoT Core	EMQX Dedicated Flex
Messaging (Ingress/Egress)	18,844 dollars	0 dollars (Included)
Rules / Processing	7,776 dollars	0 dollars (Included)
Connectivity / Instance	35 dollars	5,933 dollars
Total Monthly Cost	26,655 dollars	5,933 dollars
Total Savings		~78%

Note: If the application uses Device Shadows even moderately, AWS costs increase significantly, often pushing EMQX savings past 80%.

Additional Advantages Beyond Cost

Although the cost difference is often the headline, the architectural differences between the platforms matter as well.

1. Multi-cloud and hybrid deployment flexibility

AWS IoT Core runs only on AWS. EMQX can run on AWS, Azure, Google Cloud, on-premises, or in a hybrid environment. This helps teams avoid vendor lock-in and maintain long-term portability.

2. Full compliance with MQTT standards

According to EMQ’s public comparison guide, AWS IoT Core has limitations, including the lack of QoS 2, no guaranteed message ordering, and a one-hour retry limit for QoS 1 messages. EMQX fully implements MQTT 3.x and MQTT 5, which support more advanced protocol features that some applications depend on.

3. Dedicated single-tenant architecture

EMQX Dedicated Flex provides a fully isolated MQTT cluster within a virtual private cloud. This avoids the noisy neighbor pattern common in multi-tenant environments and delivers more stable latency. EMQX includes a 99.99% uptime commitment, which is higher than the standard guarantee for AWS IoT Core.

When AWS IoT Core Still Makes Sense

AWS IoT Core is a good choice for:

• Small device deployments
• Low-frequency telemetry
• Proof-of-concept or short-term projects
• Applications already deeply tied to the AWS ecosystem

The metered cost structure is efficient for these workloads. As data volume increases or deployments reach industrial scale, EMQX becomes the more economical and flexible choice.

The Bottom Line

AWS IoT Core excels at small or intermittent workloads but becomes costly when deployments grow and data volume increases. Its pricing model charges for every message, rule trigger, and shadow update. These charges stack together and create unpredictable bills.

EMQX approaches the same problem with a capacity-based model that eliminates per-message charges and includes data processing in the base fee. The result is a more stable cost structure that often reduces IoT spending by 60 to 80%. EMQX also provides stronger MQTT compliance, multi-cloud support, and isolation benefits that many large deployments require.

See What Your Savings Could Look Like

Use our interactive TCO calculator to get a quick comparison between AWS IoT Core and EMQX. Just enter your device count and message rate to view an estimated cost difference.

If you want to explore EMQX hands-on, you can also start a free EMQX Cloud trial.

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