Building Scalable, Secure OAuth 2.0 Integrations in Pega – Patterns and Pitfalls

What Is OAuth 2.0? => OAuth 2.0 is like a security pass system that lets two systems trust each other without needing usernames and passwords every time.

Why Use OAuth 2.0? => So, your Pega app or external systems can safely share data or perform actions. Instead of sharing passwords, they exchange tokens, short-lived "keys" that prove permission.

What Is a Client ID and Client Secret? => Think of Client ID as your app’s username and Client Secret as your app’s password.

1. Client ID – Public name that identifies your app (safe to share).
2. Client Secret – Private password that proves your app’s identity (keep this safe). You use these two to ask for a token from another system.

Example Analogy:

1. You (Pega) go to a hotel front desk (External API)
2. You show your Client ID (who you are)
3. You give your Client Secret (prove you’re legit)
4. The hotel gives you a Room Key (Access Token)
5. You use the Room Key (Token) to enter the room (API access)

What Is an Access Token? =>An Access Token is a short-term key that proves your app is allowed to access something.

Example Token (JWT): =>eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvZSIsImlhdCI6MTUxNjIzOTAyMn0.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c

This token contains:

1. Header – What kind of token it is
2. Payload – Who you are, what you can do (scope), and when it expires (exp)
3. Signature – To make sure it hasn’t been tampered with

What Is a Refresh Token? =>A Refresh Token is like a VIP pass that lets you get a new Access Token when the first one expires without logging in again.

1. Access Token – Short-term (5-30 minutes)
2. Refresh Token – Longer-term (hours, days)

Part 1: When Other Systems Call Pega (Inbound / Service REST) =>Scenario: External systems (like partner apps) want to call your Pega APIs.

What You Need to Do:

1. Create an OAuth 2.0 Client Registration
2. Upon creating the rule, ensure to view and download the credentials before saving the registration rule form.
3. Define Authorization Code - Used for user login flows (SSO). Not typical for system-to-system APIs.
4. Client Credentials – External systems use Client ID and Secret to get a token on behalf of an Operator or Access Group.
5. Operator ID / Access Group Context – Pega needs to know which operator context to apply when issuing the token. (Example: Set it to ApiServiceOperator to control what access the token grants.)
6. Token Expiry (in seconds) - Defines how long the access token is valid. (Example: 3600 seconds = 1 hours). After expiry, the client must request a new token.
7. User Profile Mapping (JWT Generation Profile (pyDefaultUserInfoMapping)) – Controls what user information is embedded in the token. I recommend leave it as default, unless you have custom JWT claims to include. (Example: Operator ID, Access Group, Email, Roles.)
8. Secure Your Service REST or Service Package with OAuth 2.0

Token Validation Steps:

1. Check aud (is this token really for my Pega app?)
2. Check scope (is the caller allowed to do this action?)
3. Check exp (has the token expired?)

Flow Example:

External System => Sends Token => Pega Service Package (OAuth 2.0 Auth) => Pega API (Service REST)

Note: You only need a full Authentication Service rule if you are replacing user login (SSO for UI login). For API access, securing the Service Package or REST Rule with OAuth 2.0 is sufficient.

Part 2: When Pega Calls Other Systems (Outbound / Connect REST) =>Scenario: Pega needs to call external APIs (like Microsoft, Salesforce, etc.) Quick Option: Authentication Profile Only

1. Fill Client ID, Client Secret, and Token URL received from the Service provider in an Authentication Profile
2. Attach it to Connect REST

Flow Example: Pega Connect REST => Authentication Profile => Token Request => External API

Monitoring & Logging Tip

1. Monitor token failures (401 errors) in Admin Studio or logs
2. Track token expiry and refresh events
3. Add custom log messages when tokens are fetched or rejected.

Pre-Go-Live Testing Checklist

1. Validate successful token retrieval
2. Validate token is added to API calls
3. Simulate expired token and confirm refresh works
4. Simulate invalid token and confirm rejection
5. Validate all logs capture token activity
6. Validate correct scopes are enforced

Final Developer Checklist

1. Pega as Service (Inbound)=> Client Registration + OAuth 2.0 Authentication on Service Package or Service REST Rule
2. Pega as Client (Quick)=>Authentication Profile Only
3. Pega as Client (Advanced)=>Client Registration + Token Profile + Authentication Profile + Connect REST Rule

Real Example =>3M+ API calls/month with zero failures using reusable token management and proper validation.

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