OAuth2 Token Format Selection — Choosing Between Opaque, JWT, and Structured Tokens

In this tutorial, you will learn about OAuth2 Token Format Selection. We cover key concepts, practical examples, and best practices to help you master this topic.

OAuth2 token format selection chooses between opaque tokens (random strings requiring introspection), JWT tokens (self-contained with claims), and custom structured tokens based on your architecture, performance needs, and revocation requirements.

flowchart TD
    A["Choose Token Format"] --> B{"Need self-contained
claims?"}
    B -->|"Yes"| C["JWT Access Token"]
    B -->|"No"| D{"Revocation speed
critical?"}
    D -->|"Yes"| E["Opaque Token (DB lookup)"]
    D -->|"No"| F["JWT (short TTL)"]

    C --> G[" + JWKS for verification"]
    C --> H[" + cnf claim for binding"]
    E --> I[" + Introspection endpoint"]
    E --> J[" + Cache introspection results"]
    F --> K[" + Blacklist for revocation"]

    L["Recommended: JWT for access + opaque for refresh"]

What's Next

Choose formats for your {{< ilink "OAuth" "OAuth2 Authorization Server" }} and review {{< ilink "OAuth" "OAuth2 JWT" }} for JWT token implementation.