Strategic Considerations in API Gateway Design: Balancing Action-Based Pricing and Architectural Clarity

In the evolving landscape of API architecture, selecting the right gateway solution is crucial, especially when pricing models and scalability are involved. Recently, I encountered a discussion that underscores the importance of understanding how billing approaches—particularly action-based or endpoint-based pricing—can influence architectural decisions. While I am sharing this from a general perspective, the insights can resonate broadly with large-scale API design considerations.

The core dilemma revolves around a vendor’s pricing structure that charges based on the number of “actions” or “endpoints”. This approach prompts a reevaluation of API structuring strategies, especially when considering the balance between minimizing costs and maintaining maintainable, clear code.

Context: Traditional vs. Consolidated Endpoint Design

In many backend frameworks, including those following RESTful principles, controllers group related actions—such as creating, retrieving, updating, and deleting resources. For example:

• WidgetsController
• CreateWidget()
• GetWidgets()
• DeleteWidget()
• UpdateWidget()

However, some development teams employ a pattern where specific actions are defined for distinct use cases, such as:

• GetWidgetsForUseCase1()
• GetWidgetsForUseCase2()

This pattern can improve clarity by mapping closely to business logic but may lead to a proliferation of endpoints.

Vendor Incentives and Architectural Considerations

In the scenario under discussion, a service provider suggested consolidating multiple narrowly scoped actions into fewer endpoints by leveraging request parameters or flags to control behavior. They also proposed managing some of this logic at the gateway level, potentially reducing the number of billed actions.

While this approach can seem appealing financially, it raises several questions:

• Architectural Clarity: Combining multiple behaviors into a single endpoint can complicate the codebase, making it harder to understand, test, and maintain.
• Response Complexity: Handling varied responses based on complex internal logic can introduce additional overhead and potential for bugs.
• Performance Impacts: More extensive internal logic and conditional branching might affect response times, especially under high load.
• Evolution and Scalability: As requirements grow, maintaining multifaceted endpoints can become unwieldy.

Balancing Costs and Design Principles

The key question is whether consolidating multiple actions into a single, more complex endpoint offers tangible benefits over maintaining narrowly scoped, focused endpoints. Some general guiding principles include:

• **Maintainability