MQTT COMPARISON
3 min readMQTT vs HTTP: Which to Use for IoT
HTTP is a request/response protocol built for the web: the client asks and the server answers, and it must ask again to get anything new. MQTT is a publish/subscribe protocol built for devices: a long-lived connection lets the broker push messages the instant they are published, with far less per-message overhead. For frequent, small, bidirectional IoT messaging, MQTT usually wins.
HTTP powers the web; MQTT powers device fleets. Both move data between machines, but they were designed for opposite situations — one for occasional page and API requests, the other for a constant stream of small messages to and from many devices.
Two different models
HTTP is request/response: a client asks and the server answers, and to get anything new it has to ask again — polling. Even over a persistent HTTP connection, nothing arrives until the client requests it. MQTT is publish/subscribe: a client opens one long-lived connection to a broker, and the broker pushes messages the instant they're published. No polling, no reconnection per message.
MQTT vs HTTP at a glance
| MQTT | HTTP | |
|---|---|---|
| Model | Publish/subscribe (push) | Request/response (pull) |
| Connection | One long-lived connection | Client-initiated per exchange |
| Header overhead | Tiny (from 2 bytes) | Larger text headers per request |
| Real-time updates | Server push, instant | Client must poll |
| Delivery guarantees | QoS 0 / 1 / 2 | Application-defined |
| Best for | Frequent small device messages | APIs, documents, occasional calls |
When to use which
Use MQTT when many devices exchange frequent, small messages and need low-latency push — telemetry, presence, commands. Use HTTP for request/response interactions: REST APIs, file downloads, and occasional calls where a persistent connection isn't worth it. They coexist happily — devices on MQTT, dashboards and integrations on HTTP. For moving that device stream into a backend pipeline, see MQTT vs Kafka.
MQTT in TBMQ
TBMQ speaks MQTT, including MQTT over WebSocket, so even browser apps get real-time push instead of polling an HTTP endpoint.
Frequently asked questions
Is MQTT better than HTTP for IoT?
For frequent, small, bidirectional device messaging, usually yes — MQTT’s persistent connection and pub/sub model push updates instantly with far less overhead than repeated HTTP requests. HTTP remains a fine choice for occasional request/response calls and REST APIs.
Does MQTT use HTTP?
No. MQTT is its own protocol that runs directly over TCP (and can be tunneled over WebSocket). It does not sit on top of HTTP, though MQTT over WebSocket does start with an HTTP upgrade handshake.
Why is MQTT more efficient than HTTP?
MQTT has a tiny fixed header (as little as 2 bytes) and reuses one long-lived connection, so it avoids HTTP’s larger headers and the cost of opening a connection per request. Over many small messages that overhead adds up.
Can MQTT and HTTP be used together?
Yes, and they often are: devices talk to the broker over MQTT for real-time messaging, while dashboards and integrations use HTTP/REST APIs to read state or configure the system.
Run it yourself
TBMQ is a free, open-source MQTT broker built to scale. Spin it up in minutes or try the live demo — no install required.