Linking a CAP OData Service with ServiceNow using UI5

Sagar Gupta · a month ago

When you build ERP-style extensions, it’s common to have data and logic running in SAP (or any OData-compatible backend) and workflows running on ServiceNow. In my case, I used SAP Cloud Application Programming (CAP) to expose an OData V2 service. Then I wired it to ServiceNow using a small SAPUI5 app that communicates with both the CAP OData endpoint and the ServiceNow Table API.

In this blog, I’ll walk through a simple end-to-end example so you can adapt it for your own ERP Canvas or custom apps.

Prerequisites

Basic familiarity with CAP (Node.js flavor).
A ServiceNow instance with a table you can write to (or a POC table).
SAPUI5 or Fiori tooling (Business Application Studio, VS Code with UI5 tooling, etc.).

Scenario Overview

The architecture has three main pieces:

CAP service

- Exposes an OData V2 endpoint

- Contains an entity for CRUD example

ServiceNow Table API

- REST endpoint to insert records to ServiceNow table

UI5 App (Bridge)

- Uses CAP OData as default model

- Uses JSON model to call ServiceNow REST API

Goal: Post records into CAP OData and ServiceNow from a single UI.

STEP 1 – Create and expose your CAP OData service

Initialise project:

cds init cap-odata-servicenow
cd cap-odata-servicenow

Define a simple data model in db/schema.cds:

namespace demo;
entity Products {
  key ID          : UUID;
  Name            : String(111);
  Description     : String(255);
  ReleaseDate     : Date;
  Price           : Decimal(9,2);
  Rating          : Integer;
}

Expose it via service in srv/service.cds:

using demo from '../db/schema';
service CatalogService {
  entity Products as projection on demo.Products;
}

Enable OData V2 compatibility (optional but useful when integrating with tools expecting V2):
```
npm install /cds-odata-v2-adapter-proxy
```

Wire the adapter into your server.js (or equivalent) so that V2/OData/OData.svc serves the V2 endpoint.

Run the CAP app locally:
```
cds watch
```

URL generated (example): http://localhost:4004/V2/OData/OData.svc/

STEP 2 – Create UI5 app and consume both systems

Next, create a small SAPUI5/Fiori app. In my project, the manifest defines two data sources:

serviceNowService – the CAP OData V2 endpoint.
mainService – the ServiceNow Table API.

An excerpt from manifest.json looks like this:

"dataSources": {
  "serviceNowService": {
    "uri": "/V2/OData/OData.svc/",
    "type": "OData",
    "settings": {
      "annotations": [],
      "localUri": "localService/serviceNowService/metadata.xml",
      "odataVersion": "2.0"
    }
  },
  "mainService": {
    "uri": "/api/now/table/sn_hr_core_saps4hanapoc_import",
    "type": "REST"
  }
},
"models": {
  "": {
    "dataSource": "serviceNowService",
    "preload": true,
    "settings": {}
  },
  "serviceNowRest": {
    "type": "sap.ui.model.json.JSONModel",
    "uri": "/api/now/table/<table_name>"
  }
}

A few key points:

The default model ("") is an OData model bound to serviceNowService (your CAP OData service).
The serviceNowRest model is a JSONModel pointing to the ServiceNow Table API endpoint.
This lets the same app talk to both systems: OData via the default model and REST via the JSON model.

STEP 3 – Controller logic to POST data

In the main view controller (View1.controller.js), I implemented two handlers:

onPostOData – Posts a new Products entry to the CAP OData service.
onPostServiceNowRest – Posts an HR import row to the ServiceNow table via REST.

Here is the core logic (simplified) from View1.controller.js:

onPostOData: function () {
  var oModel = this.getView().getModel(); // default OData model
  var oEntry = {
    Name: "New Product",
    Description: "Sample Description",
    ReleaseDate: "/Date(1622505600000)/",
    Price: 99.99,
    Rating: 5
  };

  oModel.create("/Products", oEntry, {
    success: function (oData, response) {
      MessageToast.show("Product created successfully! (Status: " + response.statusCode + ")");
    },
    error: function (oError) {
      var statusCode = oError.statusCode || (oError.response && oError.response.statusCode) || "Unknown";
      MessageToast.show("Error creating Products. (Status: " + statusCode + ")");
    }
  });
},

This is enough for a working E2E proof of concept:

Click “Create Product” → data goes to CAP OData.
Click “Create HR Import Row” → data goes to ServiceNow Table API.

STEP 4 – Run UI and verify

In your XML view, add two buttons and bind them to the controller methods:

<Button text="Post to OData" press=".onPostOData" />
<Button text="Post to ServiceNow" press=".onPostServiceNowRest" />

Run the UI5 app (e.g. npm start or via ui5 serve depending on your tooling).
Open the app in the browser and try both buttons:
- Validate that CAP receives and persists the Products record.
- Verify in ServiceNow that a new row was inserted into your table.

Once this works locally, you can deploy:

CAP service → SAP BTP (or another Node runtime).
UI5 app → wherever you host your Fiori/UI5 apps.
Ensure the URLs and destinations are adjusted accordingly.

STEP 5 – Extending into ERP Canvas

In more advanced scenarios, you can:

If you want to create/read/update data in SAP using an exposed OData v2 endpoint, use Zero Copy Connector for ERP to model operations over the CAP OData service (for example, using a “Model creation using OData Service” pattern similar to other ServiceNow guides). ServiceNow
Use the CAP OData service as your SAP-side abstraction and the ServiceNow Table API as your workflow/case-management side.
Keep your CAP logic focused on data & business rules, and let ServiceNow handle approvals, tasks, and notifications.

The simple UI5 bridge shown here is mainly for:

Prototyping end-to-end flows.
Testing connectivity and payloads.
Providing a reference for how CAP OData and ServiceNow REST can be used together.

Tips:

Use OAuth/credentials for ServiceNow securely
Add error logging when scaling production use
Maintain consistent field mapping between SAP ⇆ SNOW

Conclusion

We successfully connected the CAP OData service with ServiceNow using a UI5 application. This flexible architecture enables bi-directional integration, real-time data operations, and plug-in to ERP Canvas or automation frameworks. This serves as an excellent boilerplate for larger projects.