How Spec-First API Documentation Aids Partner Integration

Partner APIs are far more common than public-facing APIs. Yet, inaccessible documentation for these APIs is often a big barrier to partner success. In fact, nearly 40% of developers say inconsistent docs are their biggest roadblock when it comes to API integration, found the 2024 State of the API Report. Pain points around API documentation can cause miscommunications, errors, and time delays.

A documentation-first approach based on specifications can help resolve many of the issues tied to API consumption. Spec-first API documentation, especially when managed in a git-based environment, provides a consistent, single source of truth that drives integration success and strengthens partner relationships. Below, we'll review the status quo for documentation and see how this solution can lead to happier partners and boost your overall revenue.

Why We Need to Shift Documentation Left

Although RESTful APIs have been around for decades, the status quo for API documentation is still weak, to say the least. Reports show that API documentation is far from comprehensive. In fact, an EMA study from 2023 found that only 10% of organizations fully document their APIs. When APIs are documented, too often, a lack of development guardrails and standard guidelines hold back stunning API documentation that developers love.

An unsurprising dilemma of poor documentation practices is specification drift. A troubling 2024 APIContext report found that 75% of APIs have nonconformant endpoints, meaning their documentation drifts from production behaviors. Incomplete documentation, a lack of specification-driven approaches, and immature change management often are root causes of API specification drift.

Poor documentation practices might not seem like a big issue from the onset. However, it can cause major downstream problems for consumers. For one, incomplete documentation can hurt discoverability and developer experience, leading to fewer customers and a loss of revenue. Worse, broken client integrations can lead to unhappy partners and decrease product stickiness.

Understanding Shift-Left and Documentation-First

One answer to these issues lies in shifting documentation practices left. By focusing on documentation earlier in the pipeline, API providers are far better equipped to produce more accurate, detailed descriptions and evolve their service more effectively.

In the context of API documentation, shift-left refers to creating and documenting the specification before development. This differs from a code-first approach, which typically involves coding the API and generating documentation after the fact. Instead, a documentation-first takes a more ground-up approach to base development on descriptions like OpenAPI specifications. This helps standardize API behaviors from the onset.

A documentation-first practice based on API specifications also aligns with modern DevOps practices, like continuous integration and continuous delivery (CI/CD). This is enabled by taking a git-based approach to documentation, wherein all stakeholders pull from and make changes to the same specification in a shared repository. Git-based workflows — tools developers use to collaboratively manage and version code — ensure everyone is working from the same playbook, reducing errors and miscommunication. Uniting everyone in source control goes a long way to ensure all collaborators, from API developers to technical writers, QA testers, and project managers, are on the same page.

This git-based workflow helps maintain an authoritative source of truth. Building from specifications in this way ensures consistency for the API implementation and accuracy for developer consumer-facing resources like API references, software development kits (SDKs), and libraries since they all rely on a shared repository. Collaborators can also see changes and collaborate in real-time, as opposed to siloed development.

Spec-First Docs Improve Partner Relationships

So, how do these shift-left API documentation development practices benefit partners? A better documentation culture ensures that all APIs are accounted for and well-described. This can significantly aid the partner API experience. Documentation-first practices reduce integration friction and ease onboarding, resulting in a quicker time to value for partners.

For instance, say you are a major retailer exposing your product data for affiliate partners to embed into their sites. If partners can't quickly find the right product information API or fields are incomplete, they may turn to screen-scraping techniques or other data providers entirely. Resolving specification drift also means fewer breaking changes on the client side. Going back to our retail API, if the documentation doesn't match production behavior, this could easily result in mismatched product information fields.

Utilizing OpenAPI as a source of truth also ensures fewer errors and more reliable communication with your partners as APIs evolve. On that note, many developer consumers prefer using their internal tools to work with the actual description. Having faith that the OpenAPI YAML or JSON file you expose is accurate goes a long way to establishing trust.

Partners shouldn't have to rely on contract testing to ensure the APIs they integrate with meet their expectations or service-level agreements (SLAs). Specification-driven API development is like a built-in predictability of following a contract. While each system has certain nuances that specifications can't fully describe, for the most part, if your team is aligned on specification-first, what you see is what you get.

Lastly, following open standard specifications helps you take advantage of industry momentum, such as leveraging new features in OpenAPI's incoming Moonwalk or utilizing the Arazzo specification, an extension to OpenAPI that provides a standard way for API providers to described interlinked calls.

In-Sync API Docs = Happy, Stable Partners

Impressive developer programs, from AirBnb to eBay, Shutterstock, Kroger, and beyond, prove there's a high business value in partner API programs. And, studies have shown that APIs drive significant portions of revenue for digital businesses. For instance, 21% of companies derive over 75% of revenue from APIs, according to the Postman 2024 State of the API Report. Since APIs are products, improving the developer experience through great documentation is an essential step toward unlocking this revenue potential.

In short, APIs are how businesses speak to one another. Breaking this oath with a poor integration experience is a surefire way to reduce your business potential. By utilizing a source of truth and baking a specification-first approach into your API development and documentation practices, you more clearly communicate changes, reducing the possibility of broken clients and promoting forward compatibility. Great API products must be well-described, easy to understand, and predictable in the long run.

In the end, the business effects of specification-driven development are manifold. Whether you're building RESTful, GraphQL, or event-driven partner services, having reliable API documentation is important to compete in the digital economy. This consistency equates to a better partner experience, leading to stickier partners and less customer churn. By enabling smoother integrations and reducing frustration, spec-first documentation directly contributes to partner retention and loyalty, which ultimately drives revenue growth.