OAuth Sequence Diagram Pattern
A user authentication flow where a client application redirects to an authorization server, exchanges an authorization code for tokens, then accesses a resource API with token validation and refresh handling.
“Create a UML sequence diagram for OAuth 2.0 PKCE login with Browser, Frontend App, Authorization Server, and Resource API. Show authorization request, redirect back with code, code exchange, access token use, refresh token rotation, and expired refresh token error path.”
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Scenario summary
A user authentication flow where a client application redirects to an authorization server, exchanges an authorization code for tokens, then accesses a resource API with token validation and refresh handling.
Why this architecture matters
- 1
OAuth implementations fail on message ordering details, so a sequence diagram prevents hand-wavy auth documentation.
- 2
It exposes where redirects, token exchange, refresh rotation, and error handling actually happen.
- 3
It gives frontend, backend, and security teams one artifact to review before shipping login changes.
Refine it with follow-up prompts
After generating the base diagram, use these prompts to iterate and add detail — the same way a real architect would refine a whiteboard sketch.
- 1
“Add an MFA branch after primary authentication.”
Try this follow-up - 2
“Show logout and token revocation flow.”
Try this follow-up - 3
“Add annotations for where tokens are stored and validated.”
Try this follow-up
What to emphasize in the diagram
- •List actors in the real request order from left to right.
- •Include both happy path and token failure or expiry paths.
- •Label token exchange and validation steps explicitly to avoid ambiguity.
How AIDrawIO generates this diagram
- 1.You paste the prompt above into the chat input.
- 2.AIDrawIO sends it to your chosen AI model (GPT-5, Claude, or Gemini).
- 3.The model returns draw.io-compatible XML — rendered instantly in the canvas.
- 4.Export as SVG, PNG, or XML. Edit any element manually or with follow-up prompts.
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Frequently asked questions
Why use a sequence diagram for OAuth?
OAuth is message-order dependent, so a sequence diagram is the clearest way to show redirects, token exchange, validation, and alternate paths.
Should I include refresh token logic?
Yes. Refresh and expiry behavior are often the most important parts of the flow for engineers and reviewers.