Business Central API Integration Extension – Step‑by‑Step Manual

codeunit 50100 "API Client Demo"
{
    // Simple demo: GET and POST using HttpClient

    procedure GetSampleTodo(): Text
    var
        Client: HttpClient;
        Response: HttpResponseMessage;
        BodyText: Text;
        JObj: JsonObject;
        JTok: JsonToken;
        Title: Text;
        Id: Integer;
        Completed: Boolean;
    begin
        if not Client.Get('https://jsonplaceholder.typicode.com/todos/1', Response) then
            error('Request failed.');

        if not Response.IsSuccessStatusCode() then
            error('HTTP error %1 %2', Response.HttpStatusCode(), Response.ReasonPhrase());

        Response.Content().ReadAs(BodyText);
        JObj.ReadFrom(BodyText);

        JObj.Get('id', JTok);
        Id := JTok.AsValue().AsInteger();

        JObj.Get('title', JTok);
        Title := JTok.AsValue().AsText();

        JObj.Get('completed', JTok);
        Completed := JTok.AsValue().AsBoolean();

        exit(StrSubstNo('Todo %1: %2 (Completed: %3)', Id, Title, Format(Completed)));
    end;

    procedure PostEchoSample(): Text
    var
        Client: HttpClient;
        Request: HttpRequestMessage;
        Response: HttpResponseMessage;
        Content: HttpContent;
        Headers: HttpHeaders;
        Result: Text;
    begin
        // Define JSON body
        Content.WriteFrom('{"message": "Hello from Business Central"}');
        Content.GetHeaders(Headers);
        Headers.Clear();
        Headers.Add('Content-Type', 'application/json');

        // Build request
        Request.Method := 'POST';
        Request.SetRequestUri('https://postman-echo.com/post');
        Request.Content := Content;

        // Send request
        if Client.Send(Request, Response) then begin
            Response.Content.ReadAs(Result);
            exit(Result);
        end else
            exit('Error: No response received.');
    end;
}

pageextension 50100 "Customer List API Demo" extends "Customer List"
{
    actions
    {
        addlast(Processing)
        {
            action(GetTodo)
            {
                ApplicationArea = All;
                Caption = 'Get Sample To‑Do';
                Image = Information;
                trigger OnAction()
                var
                    ClientDemo: Codeunit "API Client Demo";
                    Msg: Text;
                begin
                    Msg := ClientDemo.GetSampleTodo();
                    Message(Msg);
                end;
            }
            action(PostEcho)
            {
                ApplicationArea = All;
                Caption = 'Send Echo POST';
                Image = Send;
                trigger OnAction()
                var
                    ClientDemo: Codeunit "API Client Demo";
                    Msg: Text;
                begin
                    Msg := ClientDemo.PostEchoSample();
                    Message(Msg);
                end;
            }
        }
    }
}

{
"args": {},
"data": {
"message": "Hello from Business Central"
},
"files": {},
"form": {},
"headers": {
"host": "postman-echo.com",
"x-request-start": "t1755375774.621",
"connection": "close",
"content-length": "42",
"x-forwarded-proto": "https",
"x-forwarded-port": "443",
"x-amzn-trace-id": "Root=1-68a0e89e-76658f302fdafd186f534932",
"x-from-al": "*",
"traceparent": "00-d72353840ebc4037aecfda60b8fccc2d-b6449032859570f8-01",
"baggage": "traceStartInfo=%5BWeb+Client+-+Web+browser%5D+OpenForm+-+Opening+page+with+id+%2722%27",
"correlation-context": "traceStartInfo=%5BWeb+Client+-+Web+browser%5D+InvokeAction+-+The+user+clicked+on+%27PostEcho%27+on+%27Customer+List%27, clientInteractionName=InvokeAction, clientInteractionFriendlyDescription=The+user+clicked+on+%27PostEcho%27+on+%27Customer+List%27",
"content-type": "application/json"
},
"json": {
"message": "Hello from Business Central"
},
"url": "https://postman-echo.com/post"
}

page 50110 "Customer Lite API"
{
    PageType = API;
    SourceTable = Customer;
    APIPublisher = 'navplanet';
    APIGroup = 'tutorial';
    APIVersion = 'v1.0';
    EntityName = 'customerLite';
    EntitySetName = 'customerLites';
    ODataKeyFields = SystemId; // Required for custom APIs
    Caption = 'Customer Lite API';

    layout
    {
        area(Content)
        {
            repeater(General)
            {
                field(systemId; Rec.SystemId)      { Caption = 'System Id'; }
                field(no; Rec."No.")               { Caption = 'No'; }
                field(displayName; Rec.Name)       { Caption = 'Name'; }
                field(city; Rec.City)              { Caption = 'City'; }
                field(phone; Rec."Phone No.")      { Caption = 'Phone'; }
            }
        }
    }
}

permissionset 50100 APIDemo
{
    Assignable = true;
    Caption = 'API Demo - Basic';
    Permissions =
        tabledata Customer = r,
        page "Customer List" = X,
        codeunit "API Client Demo" = X,
        page "Customer Lite API" = X;
}

local procedure EnsureSuccess(Response: HttpResponseMessage)
begin
    if not Response.IsSuccessStatusCode() then
        error('HTTP %1 %2. Body: %3',
              Response.HttpStatusCode(),
              Response.ReasonPhrase(),
              GetBody(Response));
end;

local procedure GetBody(Response: HttpResponseMessage): Text
var
    T: Text;
begin
    Response.Content().ReadAs(T);
    exit(T);
end;