website static MQTT examples at https://hpssjellis.github.io/my-examples-of-iot-platforms/public/index.html
By @rocksetta
https://flespi.com/
https://io.adafruit.com/
https://www.hivemq.com/
http://www.dioty.co/
https://tago.io/
https://thingspeak.com/
Pascalbod This is a resemably uptodate list of IOT websites. Same as the one below after the twitter list.
https://www.capterra.com/sem-compare/iot-software/
https://www.gartner.com/reviews/market/iot-platforms
https://thetechmusk.com/best-iot-platforms-review-going-top-in-2021/
https://www.g2.com/categories/iot-platforms/free
https://www.g2.com/categories/iot-platforms
https://www.softwaretestinghelp.com/best-iot-platforms/
https://www.afero.io/
https://aggregate.digital/
https://www.sierrawireless.com/products-and-solutions/iot-connectivity/iot-cloud-platform/
https://akenza.io/
https://www.altair.com/smartworks/
https://docs.arduino.cc/cloud/iot-cloud
https://www.arkessa.com/
https://asksensors.com/
https://atmosphereiot.com/
https://www.avimesa.com/
https://aws.amazon.com/iot/
https://www.ptc.com/en/products/thingworx
https://www.aylanetworks.com/
https://www.balena.io/
https://beebotte.com/
https://blynk.io/
https://www.boltiot.com/home
https://bosch-iot-suite.com/
https://www.busit.com/en/product-2/
https://banyanhills.com/canopy-iot-platform/
https://developers.mydevices.com/cayenne/features/
https://www.clovity.com/csensornet/
https://www.rti.com/products
https://www.connio.com/industrial-iot-industrial-iot-platform.html
https://www.softwareag.cloud/site/product/cumulocity-iot.html#/
https://www.dataplicity.com/
https://davra.com/iot-platform/
https://www.digi.com/products/iot-software-services/digi-remote-manager
https://www.digi.com/products/iot-software-services/digi-remote-manager
http://dweet.io/
https://www.edgeiq.ai/platform
https://www.electricimp.com/platform/how-it-works/
https://www.embever.com/
https://www.emnify.com/
https://freeboard.io/
https://www.gaonic.com/
https://www.go-iot.io/
https://docs.golioth.io/
https://cloud.google.com/solutions/iot
https://iotfy.com/platform
https://ifttt.com/about
https://www.globeranger.com/solutions/
https://www.initialstate.com/
https://www.inteliments.com/en/products-and-services/iot-data-platform
https://io.adafruit.com/
https://infiswift.tech/iot-ai-fabric/
https://iotguru.cloud/
https://www.hologram.io/
https://www.kaaiot.com/
https://en.kii.com/platform/
https://liveobjects.orange-business.com/#/liveobjects
https://litmus.io/litmus-edge-manager/
https://www.losant.com/iot-platform
https://www.hitachi.com/products/it/lumada/global/en/about/
https://luner.io/
https://www.m2mi.com/index.php/m2m-iot-application
https://macchina.io/index.html
https://www.tinkermode.com/
https://www.munic.io/
https://www.exosite.com/murano-iot-platform
https://mydevices.com/platform/
https://www.nabto.com/
https://www.aeris.com/neo/
https://www.net4things.com/mobility/platform/
https://dev.netatmo.com/
https://www.netobjex.com/technology/
https://niolabs.com/
https://www.nexess-solutions.com/en/iot-platform/
https://www.sierrawireless.com/octave/
https://otonomo.io/platform/
https://pelion.com/
https://podgroup.com/
https://www.pubnub.com/
https://pycom.io/products/software/pybytes-3/
https://reekoh.com/
https://saymon.tech/
https://signomix.com/#!en
https://www.wirelesslogic.com/iot-solutions/simpro/
https://smart-ix.ai/
https://www.smartthings.com/
https://thethings.io/
https://www.thingsmobile.com/business
https://thingspeak.com/
https://www.thingsquare.com/iot-platform/
https://www.u-blox.com/en/product/thingstream
https://www.ptc.com/en/products/thingworx
https://www.twilio.com/blog/introducing-microvisor
https://unificationengine.com/
https://ursaleo.com/
https://internetofthings.ibmcloud.com/#/
https://wavely.io/
https://www.waylay.io/
https://wolkabout.com/platform/#first
https://yaler.net/
https://test.mosquitto.org/
https://www.emqx.com/
https://flespi.com/
https://io.adafruit.com/
https://www.hivemq.com/
http://www.dioty.co/
https://tago.io/
MQTT and possible Webhooks:
https://thingspeak.com/login
https://io.adafruit.com/
https://pipedream.com/
https://tago.io/pricing/
https://docs.akenza.io/api-reference/mqtt
https://asksensors.com/
https://www.aylanetworks.com/ayla-dev-kit-freel-trial-program.html
https://beebotte.com/overview
https://developers.mydevices.com/cayenne/docs/getting-started/#getting-started-arduino-get-started-in-minutes
https://dweet.io/play/
https://freeboard.io/#pricing
https://iotguru.cloud/
https://liveobjects.orange-business.com/#/liveobjects
https://www.losant.com/pricing
https://flespi.com/pricing ?????????????
https://www.waylay.io/
https://www.balena.io/ basically only for RaspberryPi base needing software installed
https://www.scaleway.com/en/iot-hub/ - Great site but needs credit card infor see this example https://github.com/luisomoreau/ESP32-cam-MQTT
https://login.arduino.cc/login
http://www.dioty.co/samples look at arduino code
SIM CAT-M1 or NB-IOT
https://www.hologram.io/pricing
https://www.aeris.com/neo/pricing/
Other
https://test.mosquitto.org/