API Integration in RPA

RPA bots primarily interact with the user interface — but not every system interaction has to go through the screen. When a target system offers an API (Application Programming Interface), connecting to it directly is faster, more reliable, and less prone to breaking when the UI changes. Many enterprise bots combine UI automation for legacy systems with API calls for modern systems.

What Is a REST API?

A REST API is a way for two software systems to exchange data over the internet using standard HTTP commands. When your bot makes an API call, it sends a request to a server and receives a response — typically in JSON format — without needing to open any application on screen.

Analogy: API as a Restaurant Waiter

 YOU (Bot)         WAITER (API)           KITCHEN (System)
 ─────────────────────────────────────────────────────────
 "I need the       → Request sent to       → System looks up
  balance for       the API endpoint         the data
  account #1234"
                   ← Response returned    ← Data packaged
                     in JSON format         as JSON response

 Bot reads the JSON and uses the balance value

HTTP Methods in REST APIs

Making API Calls in UiPath

UiPath provides the HTTP Request activity for making API calls. You configure the URL, method, headers, and body — then the activity returns the response as a string.

Example: GET Request – Retrieve Customer Data

 HTTP Request Activity:
 ├── URL: "https://api.crm.company.com/customers/" + accountNo
 ├── Method: GET
 ├── Headers:
 │     Content-Type: application/json
 │     Authorization: "Bearer " + apiToken
 ├── Output: responseBody (String variable)
 └── Output: statusCode (Integer variable)

 Response (responseBody):
 {
   "accountNo": "ACC-1234",
   "name": "John Smith",
   "email": "john.smith@email.com",
   "balance": 15750.00,
   "status": "Active"
 }

Example: POST Request – Create a New Order

 HTTP Request Activity:
 ├── URL: "https://api.erp.company.com/orders"
 ├── Method: POST
 ├── Headers:
 │     Content-Type: application/json
 │     Authorization: "Bearer " + apiToken
 ├── Body (JSON):
 │   {
 │     "customerId": customerID,
 │     "productCode": productCode,
 │     "quantity": quantity,
 │     "deliveryDate": deliveryDate
 │   }
 ├── Output: responseBody
 └── Output: statusCode

 Expected Response: statusCode = 201 (Created)
 responseBody: { "orderId": "ORD-789", "status": "Confirmed" }

Parsing JSON Responses

API responses come back as JSON strings. The bot must parse the JSON to extract specific field values. In UiPath, you use the Deserialize JSON activity to convert the JSON string into a JObject that you can query by field name.

 Deserialize JSON:
 Input: responseBody (String)
 Output: jsonData (JObject)

 Then extract specific fields:
 customerName = jsonData("name").ToString()
 balance      = CDbl(jsonData("balance"))
 status       = jsonData("status").ToString()

 Result:
 customerName = "John Smith"
 balance      = 15750.00
 status       = "Active"

Handling API Authentication

Most APIs require authentication to prevent unauthorised access. Common authentication methods:

API Key

A unique key sent in the request header. Simple to use.

 Header: X-API-Key: your-api-key-here

Bearer Token (OAuth 2.0)

The bot first calls an authentication endpoint to receive a temporary access token, then uses that token in all subsequent API calls.

 STEP 1: Get Token
 POST https://auth.company.com/token
 Body: { "client_id": clientID, "client_secret": clientSecret }
 Response: { "access_token": "eyJhbGci...", "expires_in": 3600 }

 STEP 2: Use Token in API Calls
 Header: Authorization: Bearer eyJhbGci...

Basic Authentication

Username and password encoded in Base64 and sent in the header.

 Header: Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ=

Status Code Handling

Every API response includes a status code that tells you whether the request succeeded or failed. Your bot must check the status code and handle different outcomes.

Real-World Integration Pattern

 USE CASE: Hybrid Bot — UI for legacy SAP + API for modern CRM

 STEP 1: Read invoice data from email (UI – Outlook)
         │
         ▼
 STEP 2: Call CRM API (GET) to retrieve customer credit limit
         URL: /customers/{customerId}/creditLimit
         Response: { "creditLimit": 50000 }
         │
         ▼
 STEP 3: IF invoice amount < credit limit:
           Enter invoice in SAP via UI (UI automation)
         ELSE:
           Call Approval API (POST) to create approval request
         │
         ▼
 STEP 4: Call CRM API (PATCH) to update invoice status
         URL: /customers/{customerId}/invoices/{invoiceId}
         Body: { "status": "Posted", "sapDocNo": sapDocNumber }
         │
         ▼
 STEP 5: Send confirmation email (UI – Outlook)

Summary

API integration allows RPA bots to interact with modern systems directly and reliably without going through the user interface. REST APIs use HTTP methods (GET, POST, PUT, DELETE) to retrieve and modify data. UiPath's HTTP Request activity handles API calls. JSON responses are parsed using Deserialize JSON. Authentication is managed through API keys, bearer tokens, or basic auth — all stored securely in Orchestrator Assets. Status code handling ensures the bot responds correctly to both success and error responses. Combining UI automation with API calls produces the most robust and efficient enterprise bots.