# MQTT Hub/Gateway

**URL:** <https://community.homey.app/t/mqtt-hub-gateway/6766>\
**Category:** Apps\
**Created:** [January 14, 2019, 6:59pm UTC](https://community.homey.app/t/mqtt-hub-gateway/6766 "2019-01-14T18:59:50Z")\
**Posts on this page:** 1\
**Showing post:** 808

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**Author:** ![robertklep](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/robertklep/32/160628_2.png) [@robertklep](https://community.homey.app/u/robertklep)\
**Post date:** [March 26, 2021, 5:56am UTC](https://community.homey.app/t/mqtt-hub-gateway/6766/808 "2021-03-26T05:56:10Z")

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~~Have you tried running the app from the command line to see if it logs any additional error data?~~

@HarriedeGroot I found the issue: apparently, an API endpoint needs to return proper JSON, otherwise `ApiApp` throws an exception. The MQTT Client API endpoints don’t return JSON, so an error is generated.

This is, of course, not documented anywhere 😖

Issue here: [ApiApp throws exception when endpoints return un-JSON-serializable data · Issue #184 · athombv/homey-apps-sdk-issues · GitHub](https://github.com/athombv/homey-apps-sdk-issues/issues/184)

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