Convert CURL to PowerQuery

[AlexisPREVOT]

Good morning,

I would like to ask for your help because I am in the process of converting a curl API request to PowerQuery.
Here is the initial query : 

curl -X POST --data '{"dept": "75", "orange_area": ["O2A"], "output_format":"JSON"}' -H "X-LAPI-KEY: <YOUR KEY>" https://portal.ielo-liazo.com/lapi/v1/geomkt/siren/search

And here is my transformation into PowerQuery : 

let

LoginURL = "https://portal.ielo-liazo.com/lapi/v1/geomkt/siren/search",
PostBody = [#"data"="dept=75, output_format=JSON"],

Header = [#"X-LAPI-KEY"="YOUR KEY"],

PostBodyEncoded = Uri.BuildQueryString(PostBody),

Source = Json.Document(Web.Contents(LoginURL,[Content=Text.ToBinary(PostBodyEncoded),Headers=Header]))
in
Source

My problem is that I have an error telling me "Could not decode json".

How can I solve it ?
Thanks in advance

[AlexisPREVOT]

Thanks for the link I just looked at.
Now I have a new error message telling me that my 'dept' parameter is not found or invalid.

I don't know what to think or do about this request.

My new request : 

let
url = "https://portal.ielo-liazo.com/lapi/v1/geomkt/siren/search",
headers = [#"X-LAPI-KEY"="KEY"],
postData = Json.FromValue([#"data"="dept=75"]),
#"CSV importé" = Csv.Document(Web.Contents(url,[Content=(postData),Headers=headers]),[Delimiter=",", Columns=2, Encoding=1252, QuoteStyle=QuoteStyle.None])
in
#"CSV importé"

[lbendlin]

let
url = "https://portal.ielo-liazo.com/lapi/v1/geomkt/siren/search",
headers = [#"X-LAPI-KEY"="KEY"],
postData = Json.FromValue([dept=75,#"output_format"="JSON"]),
#"CSV importé" = Csv.Document(Web.Contents(url,[Content=(postData),Headers=headers]),[Delimiter=",", Encoding=65001, QuoteStyle=QuoteStyle.None])
in
#"CSV importé"

[lbendlin]

Please read the documentation.  Example 2 Web.Contents - PowerQuery M | Microsoft Learn