# Is it possible to define an extra payload fields directly from TTN application different per device like an API Key

**URL:** <https://www.thethingsnetwork.org/forum/t/is-it-possible-to-define-an-extra-payload-fields-directly-from-ttn-application-different-per-device-like-an-api-key/18757>\
**Category:** Application Development\
**Created:** [October 14, 2018, 12:32am UTC](https://www.thethingsnetwork.org/forum/t/is-it-possible-to-define-an-extra-payload-fields-directly-from-ttn-application-different-per-device-like-an-api-key/18757 "2018-10-14T00:32:20Z")\
**Posts on this page:** 1\
**Showing post:** 8

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**Author:** ![gaspar](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/gaspar/32/25844_2.png) [@gaspar](https://www.thethingsnetwork.org/forum/u/gaspar)\
**Post date:** [October 18, 2018, 10:42am UTC](https://www.thethingsnetwork.org/forum/t/is-it-possible-to-define-an-extra-payload-fields-directly-from-ttn-application-different-per-device-like-an-api-key/18757/8 "2018-10-18T10:42:37Z")

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As soon I can find my problem [“ttnctl devices info” throws “Application not registered to this Handler”](https://www.thethingsnetwork.org/forum/t/ttnctl-devices-info-throws-application-not-registered-to-this-handler/18847) I’ll confirm if it’s work @arjanvanb

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