Internal API
An internal API is a non-public programming interface intended for use within a software system or organization rather than as a stable external contract.
Unit Testing Principles, Practices, and Patterns
The non-public operations and contracts through which internal implementation details are accessed within a software component.
- How it is used
- Defines which operations and state clients may rely on while keeping implementation details hidden.
- How deep it goes
- Explains classification, leakage, encapsulation, and a User refactoring, but stops short of exhaustive API design guidance.
- Examples
- Uses User.NormalizeName and MessageRenderer.SubRenderers to show leaking operations and state, then hides them behind observable behavior.
- What you can do after
- Evaluate API boundaries and refactor exposed implementation details behind operations or state that represent observable behavior.
Read how Unit Testing Principles, Practices, and Patterns explains internal API →
Secure APIs
An internal API is an API intended for use within an organization or its private infrastructure rather than for public access.
- How it is used
- Frames private APIs as sensitive operational services that require public-API security rather than network-location trust.
- How deep it goes
- Explains uses, failure modes, incidents, and layered network controls, but stops short of implementation code.
- Examples
- Uses back-office operations, a customer-identity API, public exposure mistakes, and bastion-server network diagrams as concrete examples.
- What you can do after
- Operate and configure internal APIs with authentication, authorization, private subnets, bastion access, and controlled gateway exposure.
The Design of Web APIs, Second Edition
An internal API is an application programming interface exposed for use within an organization's systems or network.
- How it is used
- Serves communication among an organization’s applications and teams while providing practice for partner and public API design.
- How deep it goes
- Defines scope, openness, design importance, and transition trade-offs but stops short of implementation details.
- Examples
- Uses SOCNET’s Backend, Friends, Search, and Face Detection APIs to contrast internal, partner, and public consumption.
- What you can do after
- Evaluate API boundaries and design internal APIs that can support current consumers and possible future exposure.
Read how The Design of Web APIs, Second Edition explains internal API →
Related concepts
- contractkind of · An API contract is a specification of the operations, data, and behavioral expectations that govern interactions between software components.
- web servicekind of · A web service is a programmatic software interface that exposes functionality or data through web technologies or network protocols, typically HTTP.
- policy information pointused by · A policy information point is a component that supplies attributes and contextual information needed to evaluate an authorization request.
- apicontrasts with · An application programming interface (API) is a defined set of operations and conventions through which software components access functionality or exchange data.
- misconfigurationproduced by · A misconfiguration is an incorrect, unsuitable, or insufficiently restrictive system or application setting that causes unintended behavior, operational problems, or security exposure.
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