Hypermedia APIs: promoting evolutionary interfaces and agentic integrations

These slides aided my talk on Hypermedia APIs and how they promote interface evolution and Agentic integration.

1. Hypermedia
APIs

2. Introduction to Hypermedia APIs
•HATEOAS (Hypermedia as the Engine of Application State) is a REST principle where
APIs include hyperlinks in responses, allowing clients to dynamically navigate resources
and actions without hardcoded URLs.

3. Introduction to Siren HATEOS format
•Siren is a hypermedia format for representing entities in HATEOAS APIs. It structures
responses with class, properties, links, and actions, allowing clients to discover
available operations and related resources dynamically—making APIs more self-
descriptive and navigable.
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4. Siren Entities

5. Errors are entities too
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6. Siren Vs MCP
Siren entities
offer richer
context
Links for
navigation:
Related
resources
Action
availability is
contextual

7. Decision Framework
Use Hypermedia/Siren when:
•Workflows change frequently (business rules evolve)
•Different users see different capabilities (permissions, state-dependent)
•You want clients (AI or human) to discover capabilities
•The server knows the business logic better than clients can
Don't overcomplicate with it when:
•Simple CRUD operations
•Client truly controls the workflow
•Performance is critical and you need GraphQL-style efficiency

8. AI Implications
Self-Documenting for Agents
•AI Agents can consume a Siren API with zero custom code—by just following hypermedia controls
Graceful Evolution
•Add new actions → AI automatically discovers them
•Remove actions → AI never tries them
Resilience
•Siren treats errors as entities too and often provides links to recover out of them
No API version coordination required
•Traditional APIs: AI needs to understand who can do what when. Hypermedia: Server only shows available actions. AI just picks
from the menu"

9. Thank You