SAML SSO login sequence diagram template

Participants in this sequence diagram

• Employee
• SaaS app (SP)
• Identity provider
• Directory / MFA

How to use this sequence diagram template

1. Click Open in the editor. The sequence diagram opens on a new page in FlowDiagram — nothing is uploaded and there is no sign-up.
2. Rename, add or delete shapes and drag them where you want; connectors stay attached as things move.
3. Drop in vendor logos from the library — 1,160 of them, including every AWS, Azure and Google Cloud service icon — or restyle it with the colour and theme controls.
4. Prefer text? Edit the Mermaid source below and paste it in through ☰ → Import diagram (see the Mermaid editor); it imports as an editable diagram.
5. Export to PNG, SVG or PDF, or press Ctrl+L for a link that carries the whole diagram.

Mermaid source

The whole template is the text below. Paste it into FlowDiagram, keep it in Git next to the code it describes, or hand it to an AI assistant to extend.

sequenceDiagram
  autonumber
  actor U as Employee
  participant SP as SaaS app (SP)
  participant IdP as Identity provider
  participant Dir as Directory / MFA
  U->>SP: Open app.example.com
  SP->>SP: No session, build AuthnRequest
  SP-->>U: Redirect to IdP with SAMLRequest
  U->>IdP: GET /sso?SAMLRequest=...
  alt No IdP session
    IdP-->>U: Login page
    U->>IdP: Username, password
    IdP->>Dir: Verify credentials and MFA
    Dir-->>IdP: Authenticated, groups
  else Existing IdP session
    IdP->>IdP: Reuse session
  end
  IdP-->>U: Auto-POST signed SAMLResponse
  U->>SP: POST /acs with assertion
  SP->>SP: Verify signature, audience, NotOnOrAfter
  SP-->>U: Set session cookie, show dashboard
  Note over SP,IdP: Trust is set up by exchanging metadata and certificates

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