Using Postman to Test Oracle Fusion REST APIs

Why Postman first, OIC second

Building an OIC integration against an Oracle Fusion REST API without first testing it in Postman is like writing code without reading the documentation. Postman lets you:

• Explore the API response structure before committing to a schema
• Test authentication without OIC overhead
• Verify parameters, filters, and expand clauses work as expected
• Save the working request as a reference for OIC configuration

Setting up OAuth authentication in Postman

1. Create a new collection
2. Under the collection’s Authorization tab: select OAuth 2.0
3. Configure:
   • Token URL: https://your-idcs.identity.oraclecloud.com/oauth2/v1/token
   • Client ID and Secret: from your IDCS confidential application
   • Scope: the API scope (e.g. urn:opc:resource:consumer::all)
4. Click Get New Access Token — Postman fetches and stores the token
5. All requests in the collection use this token automatically

Testing a Fusion REST endpoint

GET https://your-fusion.fa.em2.oraclecloud.com/fscmRestApi/resources/latest/purchaseOrders
Authorization: Bearer {{access_token}}
Content-Type: application/json

Response 200 with JSON array — success. Response 401 — token issue. Response 403 — scope/role insufficient.

Using query parameters effectively

GET /purchaseOrders?q=Status='OPEN' and CreationDate>2026-01-01
                  &fields=PONumber,VendorName,TotalAmount,Status
                  &limit=10&offset=0
                  &orderBy=CreationDate:desc

Test each parameter individually to confirm the API behaves as expected. The fields parameter is critical — without it, Fusion returns dozens of fields you don’t need.

Saving the request as documentation

Once a request works, document it in the Postman collection with:

• Description: what it does, when to use it
• Example response: paste a sample
• Parameter documentation: what each query param does

This becomes the team’s living API documentation and makes the OIC integration build much faster.

Postman environment variables

Create environments (dev, test, prod) with variables:

{
  "base_url": "https://dev-fusion.fa.em2.oraclecloud.com",
  "access_token": "{{auto-populated by OAuth}}",
  "org_id": "204"
}

Switch environments to test against different Fusion instances without changing requests.