API catalog overview

Using external libraries. Illustration.

What is an API catalog?

An API catalog is a searchable, highly-organized library of available APIs that makes it easier for consumers to find and use the APIs they care about. Private API catalogs contain every internal API within an organization, which streamlines the API management process by helping teams identify redundant code and follow organization-wide standards. In contrast, public API catalogs connect API producers with third-party consumers, which fosters developer communities, shortens feedback loops, and generates revenue. The APIs that are listed within private and public API catalogs might also include relevant artifacts—such as documentation, example requests, and tests—to help consumers reduce their time to first call.

Here, we'll discuss the different challenges that private and public API catalogs solve—and how the Postman API Platform can help. But first, we'll explore the role that API catalogs play in an API-first world.


Why are API catalogs important in an API-first world?

API-first is a development model in which applications are conceptualized and built by composing internal or external services that are delivered through APIs. This approach has grown increasingly popular in recent years, and it supports several distinct API use cases. For instance, it is essential to microservice-based architectures, in which applications are built as a collection of services that communicate with one another through internal APIs. Additionally, its emphasis on API quality provides a solid framework for teams who offer APIs as billable products to third-party consumers.

Private and public APIs play different roles in an organization's overall business strategy, but the teams that manage them can benefit equally from the improved discoverability, collaboration, and governance that API catalogs facilitate.


What is the difference between private and public API catalogs?

Both private and public API catalogs make it easier for API consumers to find the APIs that meet their needs, but each type of catalog has several distinct benefits.

Benefits of private API catalogs

A private API catalog is a unified hub for every internal API within an organization. These catalogs provide complete visibility into an organization's overall API landscape, which benefits developers and business leaders alike. For instance, private API catalogs help developers avoid writing redundant code to implement common workflows, such as user authentication. Instead, they can search for, find, and consume APIs that were developed by other teams for the same purpose. API catalogs also offer up-to-date insight on internal API usage trends across an organization, which can inform important decisions about bandwidth distribution. Finally, the centralized nature of API catalogs makes it easier for leaders to enforce an effective API governance strategy across every team in their organization.

Benefits of public API catalogs

Public API catalogs make APIs more discoverable to third-party consumers. This exposure is particularly important for companies that market their APIs as billable products, as it increases API traffic and—by extension—revenue. Public API catalogs also break down silos between API consumers and producers, which shortens feedback loops and helps producers provide adequate support.


Screenshot of private networks. Illustration.

What is API sprawl, and how do private API catalogs help?

As discussed above, many teams have chosen to modernize their technology stacks by breaking down their monolithic applications into microservices, which are connected to one another through APIs. Microservices can be deployed, provisioned, and scaled independently of one another, allowing organizations to control costs, iterate quickly, and keep up with influxes in traffic.

While microservices offer many benefits, they also introduce challenges—especially as an organization scales. For instance, it can be difficult for software architects to decide how to separate the logic of a legacy monolith. This can result in too many microservices, which often cannot be reused. Additionally, some microservices—and their APIs—may be quietly abandoned as business needs change. The resulting API landscape is opaque, difficult to manage, and prone to security breaches. In fact, Postman's 2022 State of the API report indicates that the overproliferation of microservices is one of the biggest obstacles facing API producers today.

Private API catalogs provide an antidote to this phenomenon, which is known as “API sprawl,” by allowing business and team leaders to take stock of every API within their organization's codebase. This level of visibility makes it easier to spot redundant, outdated, and non-compliant APIs, which can then be deprecated or patched as necessary. Once an API catalog is in place, teams can be more deliberate in their API development efforts, which ensures that only necessary, secure, and high-quality APIs remain in circulation.


How does Postman support API catalogs?

The Postman API Platform, which was ranked the best tool for API management by G2, offers two ways for developers to reap the benefits of an API catalog. First, organizations can list their APIs on the Public API Network, which is the world's largest hub of public API artifacts. The Public API Network enables Postman community members to:

  • Grow their developer ecosystem: Teams who make their APIs available on the Public API Network are able to connect with over 20 million developers around the world.
  • Provide direct support to consumers: Teams can use the Public API Network to publish example requests, default configurations, and documentation, which can increase API adoption and reduce ticket volume.
  • Explore and get inspired: Developers can browse assets within the Public API Network by category and team, and they can also check out noteworthy collections and workspaces that are handpicked by the team at Postman.

Additionally, teams can use the Private API Network to build a catalog of internal API artifacts. This allows them to:

  • Discover internal APIs, workspaces, and collections: The Private API Network provides full visibility into every API, workspace, and collection within an organization, which helps teams collaborate and learn from one another.
  • Govern internal API landscapes: Leaders can access reports for deeper insight into API activity within their Private API Network. For instance, reports can be used to track request volume, performance, test failures, and SLA adherence for any private API.
  • Leverage an optional approval workflow: Network managers can exercise quality control with an optional approval workflow, which ensures that only reviewed and approved artifacts get published to the private network.

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