MQTT vs HTTP for IoT: Choosing the Right Protocol for Your Deployment

Understanding the Fundamentals

HTTP: The Web's Workhorse

HTTP (Hypertext Transfer Protocol) is the foundation of web communication. Its request-response model is familiar to every developer: a client sends a request, the server processes it, and returns a response. Each interaction is stateless and independent.

MQTT: Purpose-Built for IoT

MQTT (Message Queuing Telemetry Transport) was designed specifically for constrained devices and unreliable networks. It uses a publish-subscribe model where devices publish messages to topics, and interested clients subscribe to receive them. A central broker manages all message routing.

Head-to-Head Comparison

Deep Dive: When MQTT Excels

1. High-Frequency Telemetry

When devices need to send data frequently (multiple times per second), MQTT's persistent connection eliminates the overhead of establishing new connections. A sensor publishing 10 readings per second would require 10 HTTP connections—each with TCP handshake, TLS negotiation, and header overhead—versus a single maintained MQTT connection.

2. Battery-Powered Devices

Radio transmission is the primary power consumer in IoT devices. MQTT's minimal message overhead means less time with the radio active. Studies show MQTT can reduce power consumption by 50-90% compared to HTTP for equivalent data transfer.

3. Unreliable Networks

MQTT includes built-in reliability mechanisms:

• QoS 0: Fire and forget (at most once)
• QoS 1: Acknowledged delivery (at least once)
• QoS 2: Exactly once delivery
• Retained messages: New subscribers receive last known value
• Last Will and Testament: Automatic notification when device disconnects

4. Bidirectional Communication

MQTT naturally supports server-to-device communication. The same connection used to publish sensor data can receive commands. With HTTP, you'd need to implement long-polling, Server-Sent Events, or WebSockets for similar functionality.

Deep Dive: When HTTP Excels

1. Enterprise Integration

HTTP/REST APIs are ubiquitous in enterprise software. When IoT data needs to flow into existing business systems, HTTP often provides the path of least resistance. No new infrastructure (MQTT broker), no new ports to open, no new protocols for security teams to evaluate.

2. Request-Response Patterns

When you genuinely need request-response semantics—device configuration queries, on-demand data retrieval, firmware update checks—HTTP's model is more natural. MQTT can simulate this with correlated request/response topics, but it adds complexity.

3. Infrequent Communication

Devices that communicate rarely (once per hour or day) don't benefit from persistent connections. HTTP's stateless nature actually becomes an advantage—no connection management, no keepalive overhead, simpler device firmware.

4. Simple Architectures

HTTP requires no additional infrastructure. Point your device at an API endpoint and you're done. MQTT requires deploying and managing a broker—another component to scale, secure, and maintain.

The Hybrid Approach

In practice, most sophisticated IoT deployments use both protocols strategically:

Security Considerations

Both protocols can be secured effectively:

• MQTT: TLS encryption (MQTTS on port 8883), username/password or certificate authentication, topic-level access control
• HTTP: TLS encryption (HTTPS), standard authentication mechanisms (OAuth, API keys), well-understood security model

HTTP has the advantage of decades of security tooling and expertise. MQTT security is equally robust but may require specialized knowledge.

Cereb's Approach

The Cereb platform supports both MQTT and HTTP ingestion, allowing you to choose the right protocol for each use case. Our connection management layer handles:

• Protocol translation (MQTT to internal message bus)
• Unified authentication across both protocols
• Automatic connection recovery and retry
• Message buffering for offline devices
• Protocol-agnostic data normalization