Tutorials System Design Tutorial
Authentication for Distributed Platforms — Complete Guide
Authentication for Distributed Platforms — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of System Design Tutorial on Toolliyo Academy.
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System Design Tutorial · Lesson 61 of 100
Authentication for Distributed Platforms
Basics ✓ → Scale → Interview
Scale · 2 — Distributed · ~10 min · Module 7: Security and Observability
What is this?
Authentication verifies identity — users and services — via passwords+MFA, SSO, OIDC, or mTLS for machines.
Why should you care?
ShopNest must know who the shopper is and which service is calling Payment.
See it live — copy this example
Sketch the architecture on paper. These lessons focus on concepts and trade-offs.
User: OIDC login → tokens
Service: mTLS or signed JWT from identity provider
Gateway validates user tokens before routing
Never roll your own crypto authRun Example »
This lesson uses terminal or setup steps. Run commands on your computer — the live editor appears on coding lessons.
What happened?
- Central identity for humans; strong service identity for east-west.
- Gateway checks users early so services trust fewer raw credentials.
Practice next
- Put ShopNest user login behind OIDC/SSO.
- Validate access tokens at the gateway.
- Give each service an identity.
- Shorten token lifetime + refresh flow.
- Separate employee SSO from customer identity.
Remember
Prove identity first. OIDC for users; mTLS/JWT for services. Validate at the edge.
ShopNest OIDC login
Customers sign in via OIDC; gateway checks JWTs.
Outcome: Services receive verified user ids in headers/claims.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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