POST binary file to REST API (lexoffice)

[AAArtist]

I like to upload a file to the german bookkeeping platform Lexoffice. Unfortunately there is not app for them in n8n so I tried to use there Public API. In the flow I already downloaded the file from another app and also see the binary in the editor. Clicking on “View” renders the correct PDF file.

But when sending to the lexoffice API I always get an error: {\"i18nKey\":\"bad_request_error\",\"source\":\"Required part 'file' is not present.\",\"type\":\"bad_request_error\"}

workflow

Share the output returned by the last node

{\"i18nKey\":\"bad_request_error\",\"source\":\"Required part 'file' is not present.\",\"type\":\"bad_request_error\"}

Information on your n8n setup

• n8n version: 1.31.2
• Database (default: SQLite):
• n8n EXECUTIONS_PROCESS setting (default: own, main):
• Running n8n via (Docker, npm, n8n cloud, desktop app): Docker
• Operating system: Linux

[barn4k]

hello @AAArtist

You can open the dev console (f12, console tab) and see what the exact request is being sent to the API endpoint.

[AAArtist]

Thanks for your response. Did this already and there is an object for file. My first thought was that maybe the API is wrong, but that’s not the problem. I think I don’t get how this is handled in n8n exactly.

After failing with this workflow I created a Python script which is working perfectly.