Clear-Host
$username = "login"
$password = "password"
$url = "https://votresite/api/v1/blablabla"

$base64AuthInfo = [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(("{0}:{1}" -f $username,$password)))

$MonHeader = @{
    "Authorization" = ("Basic {0}" -f $base64AuthInfo);
    "accept" = 'application/json'
}

$BodyenJson = @{
  "champ1" = 478;
  "champ2"= "Plop_OUT";
  "untruefalse"= $true
}| ConvertTo-Json

write-host $BodyenJson 

$Headers = @{
    "Headers" = @{ Authorization = "Basic $base64AuthInfo" }
}

$Result = Invoke-RestMethod $url -Method Post -Headers $MonHeader -ContentType "application/json" -Body $BodyenJson

Write-Host "Code $($Result.code)"
Write-Host "ErrorMessage $($Result.errorMessage)"
Write-Host "InfoMessage $($Result.infoMessage)"