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In 2026, you have two sensible architectures. Use the newer community RTL-433 integration when its current documentation supports your installation and you want a direct Home Assistant connection. Use MQTT when you want the most portable and inspectable design, need a remote Linux receiver, or already operate Mosquitto.
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What RTL-433 actually does
rtl_433 is open-source software that uses a supported software-defined radio (SDR) to decode transmissions from many consumer wireless sensors. Despite its name, it is not limited to 433 MHz. Common target bands include 315, 345, 433.92, 868, and 915 MHz, depending on the hardware, region, and protocol.
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Wireless sensor
↓ radio transmission
RTL-SDR USB dongle
↓ raw RF samples
rtl_433
↓ decoded events
Native Home Assistant integration or MQTT
↓
Home Assistant devices and entitiesRTL-433 is primarily a receive-only decoder. It is excellent for monitoring temperature, humidity, rainfall, wind, battery status, leaks, motion, doors, soil moisture, power, and similar telemetry. It does not normally transmit commands back to the sensor. Receiving a protocol does not mean that RTL-433 can safely or legally control the device; rolling codes, encryption, proprietary commands, and separate transmitter hardware may be involved.
#1 Best Overall
- Turn your computer, phone or tablet into a radio scanner/ham radio receiver that can receive nearly all RF signals! Compatible with Windows, Mac OS, Linux, and Android
- NESDR SMArt RTL-SDR v5 can be used for the reception of broadcast AM radio, broadcast FM radio, shortwave radio, CB radio, public security radio, trunked radio, air traffic control, ACARS (plane-ground communications), ADS-B (plane tracking), AIS (ship tracking), POCSAG (pagers), NOAA and GOES weather satellites (weather images), weather balloons, radiosondes, DAB radio, DVB-T video, Inmarsat, Iridium, and so much more!
- The best-performing low-cost RTL-SDR available anywhere! Compared with RTL-SDR v3, HF SNR is improved by up to 15dB, VHF & UHF SNR is improved by up to 6dB, tuning accuracy is improved by an average of 4x, and the frequency range is expanded all the way down to 100kHz
- v5 has a frequency capability of 100kHz to 1.75GHz and up to 3.2MHz of instantaneous bandwidth. HF reception below 25MHz is accomplished with direct sampling and requires a suitable antenna. We recommend using a Balun One Nine to make a DIY long wire or dipole antenna (sold separately, product ID B08HGSYB7R or B00R09WHT6)
- Though the direct sampling implementation of NESDR SMArt v5 is much better than any other RTL-SDR, we still recommend using an upconverter like the Ham It Up for a more fulfilling HF experience (sold separately, product ID B076CYK8XZ)
Check sensor compatibility before buying hardware
A sensor is not compatible merely because its label says “433 MHz.” The exact model, regional version, modulation, and protocol must be supported. A product sold under the same brand may use 315 MHz in North America and 433.92 MHz elsewhere.
Check the current upstream supported-device and protocol list. It includes examples such as:
- Outdoor temperature and humidity sensors
- Weather stations, rain gauges, and anemometers
- Soil-moisture and pool sensors
- Water-leak, door, window, motion, and alarm sensors
- Tire-pressure monitors
- Energy and power meters
“Supported protocol” does not guarantee that every model from a manufacturer works. If possible, identify the exact model number and country of sale before choosing an SDR.
What you need
- A supported RTL-SDR USB dongle
- An antenna appropriate for the frequency you intend to receive
- A Home Assistant host or an always-on Linux computer
- At least one compatible wireless sensor
- An MQTT broker if you choose the MQTT architecture
The receiver does not have to be beside the Home Assistant server. In fact, placing the antenna near an exterior wall, upstairs, or closer to the sensors may work better. You can attach the SDR directly to Home Assistant OS, run RTL-433 on a separate Linux host, or use a remote SDR arrangement such as rtl_tcp.
Current SDR buying caveat
Do not assume that the RTL-SDR Blog V4 is routinely available. The manufacturer announced its end of life in May 2026 after its R828D chip supply was exhausted. If buying one, use the manufacturer’s official store or authorized sellers and consult its genuine-product guidance. A current Nooelec NESDR is a practical alternative; see the official Nooelec SDR catalog.
An expensive HF bundle or upconverter is generally unnecessary for ordinary 315/433/868/915 MHz sensor monitoring. Buy an amplifier or filter only after diagnosing a weak-signal, interference, or overload problem.
Choose an architecture
| Architecture | Best for | Trade-offs |
|---|---|---|
| Newer community RTL-433 integration | A direct Home Assistant experience with fewer transport components | Community-maintained, version-sensitive, and subject to changing installation steps |
| RTL-433 through MQTT | Existing MQTT users, remote receivers, raw event inspection, and multiple consumers | More components and more opportunities for topic or discovery mistakes |
| Manual MQTT entities | Small, stable installations requiring precise names, units, and device classes | Requires understanding the decoded JSON and maintaining entity definitions |
| External Linux receiver | Home Assistant VMs, containers, or installations without convenient USB passthrough | Requires another always-on host and a network connection |
Path A: the newer Home Assistant integration
A newer community project connects RTL-433 to Home Assistant through the Home Assistant HTTP/WebSocket API rather than the older MQTT auto-discovery route. Its announcement describes features such as radio PPM-offset support, noise-floor measurement, and unique radio serial handling. Read the project’s current installation and compatibility documentation before proceeding, because menu names, supported versions, and companion add-on requirements can change.
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- Back up Home Assistant.
- Install the current RTL-433 custom integration according to its maintained documentation.
- Install its companion add-on if required.
- Attach the SDR to the Home Assistant host, or configure the supported remote-radio arrangement.
- Set the sensor’s likely frequency and any protocol filters.
- Start the radio process and wait for the sensor’s next transmission.
- Complete the integration’s device or entity setup.
- Confirm values, availability, and radio diagnostics.
This is the most direct route when it supports your Home Assistant installation. It is not necessarily the best route for an MQTT-centered system, and migration from existing MQTT entities may require removing old discovery records and cleaning up the entity registry.
Path B: the established MQTT bridge
The MQTT design is:
rtl_433 → MQTT broker → Home Assistant MQTT integrationFor automatic entity creation, an additional helper such as rtl_433_mqtt_hass.py subscribes to RTL-433 event data and publishes Home Assistant MQTT discovery configuration topics. The official discovery helper and RTL-433 integration documentation describe this architecture.
Home Assistant OS setup
- Install the Mosquitto Broker app.
- Create a dedicated MQTT user through Home Assistant’s People or Users interface, as described in the Mosquitto documentation.
- Confirm that the MQTT integration is configured in Home Assistant.
- Install the RTL-433 add-on.
- If you want automatic entity creation, install the MQTT auto-discovery add-on or run the upstream helper separately.
- Create the RTL-433 configuration under
/config/rtl_433/. - Attach the SDR to the host running the RTL-433 add-on.
- Start RTL-433 and inspect its logs for decoded events.
The add-on supports multiple .conf.template files under the RTL-433 configuration directory. Separate files are useful when you need different frequencies, protocol filters, or receivers.
Minimal configuration
A basic configuration, adapted from the add-on documentation, is:
output mqtt://HOST:PORT,user=USERNAME,pass=PASSWORD
frequency 433.92M
convert siReplace HOST, PORT, USERNAME, and PASSWORD with values reachable from the RTL-433 process. If RTL-433 runs inside a Home Assistant add-on, the broker hostname may be an internal service name rather than the Home Assistant machine’s LAN address. Do not expose an unauthenticated MQTT broker to the internet.
convert si is recommended for the MQTT discovery helper because it reduces ambiguity between imperial and metric fields. A protocol-specific example is:
output mqtt://HOST:PORT,user=USERNAME,pass=PASSWORD
frequency 433.92M
protocol 40
convert siProtocol 40 is used in the documentation as an example for Acurite 592TXR temperature/humidity sensors. It is not a universal setting for every Acurite device.
Rank #3
- Turn your computer, phone or tablet into a radio scanner/ham radio receiver that can receive nearly all RF signals! Compatible with Windows, Mac OS, Linux, and Android
- NESDR SMArt RTL-SDR v5 can be used for the reception of broadcast AM radio, broadcast FM radio, shortwave radio, CB radio, public security radio, trunked radio, air traffic control, ACARS (plane-ground communications), ADS-B (plane tracking), AIS (ship tracking), POCSAG (pagers), NOAA and GOES weather satellites (weather images), weather balloons, radiosondes, DAB radio, DVB-T video, Inmarsat, Iridium, and so much more!
- The best-performing low-cost RTL-SDR available anywhere! Compared with RTL-SDR v3, HF SNR is improved by up to 15dB, VHF & UHF SNR is improved by up to 6dB, tuning accuracy is improved by an average of 4x, and the frequency range is expanded all the way down to 100kHz
- v5 has a frequency capability of 100kHz to 1.75GHz and up to 3.2MHz of instantaneous bandwidth. HF reception below 25MHz is accomplished with direct sampling and requires a suitable antenna. We recommend using a Balun One Nine to make a DIY long wire or dipole antenna (sold separately, product ID B08HGSYB7R or B00R09WHT6)
- Though the direct sampling implementation of NESDR SMArt v5 is much better than any other RTL-SDR, we still recommend using an upconverter like the Ham It Up for a more fulfilling HF experience (sold separately, product ID B076CYK8XZ)
External Linux host
If Home Assistant cannot conveniently access USB, run RTL-433 on a separate Linux machine and publish to MQTT:
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-C si
-M time:unix:usec:utc
-F "mqtt://MQTT_HOST:1883,user=USERNAME,pass=PASSWORD,retain=0,devices=rtl_433[/id]"This is a conceptual example; adapt it to the installed RTL-433 version, broker security, and desired topic structure. The options mean:
-C si: convert measurements to SI units.-M time:unix:usec:utc: add a UTC Unix timestamp with microsecond precision.-F mqttor the full MQTT output URL: publish decoded events through MQTT.devices=rtl_433[/id]: define the device-topic layout.retain=0: do not retain ordinary event messages.
The discovery helper must use the same event-topic structure as RTL-433. If you change the devices, event, or prefix layout, update the helper’s matching topic option, including its -T setting where applicable.
How MQTT discovery works
Home Assistant MQTT discovery uses configuration topics and JSON payloads describing devices and entities. The default discovery prefix is homeassistant, although it can be changed. See the current Home Assistant MQTT documentation for the exact discovery format.
A stable unique ID prevents the same entity from being recreated as a duplicate after restarts. Retained discovery messages are useful because Home Assistant can restore device definitions after a restart, but they have a cost: a false positive or abandoned sensor can remain indefinitely.
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Changing the MQTT topic layout or identifiers can orphan old entities. If that happens, inspect the discovery topics with MQTT Explorer, publish an empty retained payload to obsolete configuration topics, and then remove unwanted entries from Home Assistant’s entity registry. The upstream helper documentation specifically recommends MQTT Explorer for inspecting topics and cleaning retained discovery data.
Test each layer before troubleshooting entities
Use this sequence instead of starting with Home Assistant dashboards.
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1. Confirm USB access
Check the host and add-on logs for the SDR. If the dongle is not detected, MQTT and entity configuration cannot help. In a VM or container, verify USB passthrough and permissions first.
If you have multiple dongles, assign stable serial numbers and select the intended device. The upstream RTL-433 README documents serial assignment and selection by serial.
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2. Confirm radio decoding
Run RTL-433 with console output before adding MQTT. A successful decode should produce structured data containing some combination of:
modelidchanneltemperaturehumiditybatteryor battery status- signal information such as RSSI
- a timestamp
Fields differ by protocol. If no events appear, troubleshoot frequency, antenna placement, sensor batteries, transmission interval, and protocol support before touching MQTT.
3. Confirm MQTT publication
Subscribe with an MQTT client or MQTT Explorer. Inspect the exact event topic and verify that the messages contain the values seen in the RTL-433 console. Confirm broker hostname, port, username, password, TLS settings, and retained-message behavior.
4. Confirm Home Assistant discovery
Check Settings → Devices & services → MQTT, the device and entity registry, and Home Assistant logs. Inspect whether discovery topics under the configured prefix are being published. If event messages exist but discovery messages do not, the helper is missing, pointed at the wrong topic, or not recognizing the decoded fields.
Common problems and fixes
| Symptom | Likely layer | What to do |
|---|---|---|
| No SDR appears | USB or host | Check host detection, USB passthrough, permissions, power, and device selection. |
| RTL-433 runs but sees nothing | RF or protocol | Check regional frequency, antenna placement, batteries, transmission interval, and supported protocols. |
| Events appear in logs but not MQTT | Broker or output | Test the broker independently and verify the MQTT URL and credentials. |
| MQTT messages appear but no entities | Discovery | Check the MQTT integration, discovery prefix, helper, recognized fields, and topic structure. |
| Wrong units or device classes | Conversion or mapping | Use SI conversion, select the intended field, and remove stale retained definitions. |
| Duplicate entities | Identifiers or retained topics | Stop duplicate publishers, stabilize unique IDs, and delete obsolete discovery topics. |
| Short range | Antenna, noise, or overload | Improve placement first; consider filtering or amplification only after diagnosis. |
No events from a known sensor
- Move the sensor close to the antenna temporarily.
- Replace its batteries and wait through a complete transmission interval.
- Test the likely regional frequency rather than assuming 433.92 MHz.
- Check the exact model against the upstream protocol list.
- Try broad decoding for identification, then narrow the protocol list once known.
- Investigate receiver noise, overload, and PPM calibration if your current integration exposes those diagnostics.
Entities have the wrong values
Some sensors publish multiple temperature fields, mixed unit fields, or separate channels. Use convert si, identify the intended JSON field, and remove old retained discovery payloads. Automatic discovery can create useful entities without producing perfect names, grouping, or device classes; manual refinement may still be necessary.
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Improve reception and reliability
- Start with antenna placement. Keep the antenna away from the computer, USB cables, metal enclosures, and dense wiring.
- Use a short, shielded USB extension. This can reduce computer-generated noise and lets you position the antenna more effectively.
- Move the receiver. A remote Linux host or networked SDR near the antenna may outperform a receiver beside Home Assistant.
- Check overload before adding gain. An LNA can improve a weak signal, but it can also amplify interference and overload the SDR.
- Add a filter only for a diagnosed interference problem. Choose one for the relevant band rather than buying an unrelated accessory.
- Use protocol filtering after discovery. Narrowing the decoder can reduce clutter and false positives.
- Use multiple SDRs carefully. Separate devices can monitor different bands or configurations, but assign stable serial numbers and avoid USB contention.
Should you use MQTT or the newer integration?
Choose the newer community integration when its current documentation supports your Home Assistant version and you want a direct, Home Assistant-focused setup with fewer transport components.
Choose MQTT when you already run Mosquitto, need a receiver outside the Home Assistant host, want to inspect raw events, need several applications to consume the data, or require complete control over topics and entity definitions. MQTT remains the more portable and transparent architecture, even though it is no longer the only current route.
Back up Home Assistant before replacing a working MQTT installation. Treat community integrations as version-sensitive and check their current documentation before upgrading.
Alternatives for a new installation
If you have not purchased sensors yet, Zigbee, Z-Wave, or Thread may be better choices for new installations where two-way control, standardized pairing, and predictable Home Assistant support matter. They require different coordinators and usually mean replacing existing 433 MHz sensors.
A dedicated gateway such as RFXCOM may suit readers who prefer appliance-like hardware and supported 433 MHz integrations, though it is generally less open and may cost more than an RTL-SDR setup. ESP-based RF gateways can also be useful, but their protocol coverage and transmit behavior vary and must be checked for the exact sensor.
Final recommendation
Begin with compatibility and radio placement, not entity configuration. Confirm that the SDR is visible, decode one sensor locally, then verify MQTT or the native transport, and only then configure Home Assistant discovery. Use the newer integration when it fits your current installation; use MQTT when portability, remote receivers, inspection, or custom entity control matter. Once the system works, narrow the protocol list and remove stale discovery records so a noisy radio environment does not turn into a collection of false or duplicate entities.
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