How do you scale and update your app's API integration as your app grows and changes?

The second sentence states, "... and compatible with your app's technology stack." This is flat-out incorrect. The whole point of APIs is to be interoperable across technology stacks.

Also factor in how the provider will be supporting updates/changes over time. Will they be notifying consumers when new versions are available? Are they guaranteeing backwards compatibility? Will API documentation be kept up to date?

The first step is to choose the right APIs for your app's needs and goals. You want to select APIs that are reliable, secure, well-documented, and compatible with your app's technology stack. You also want to consider the cost, performance, availability, and maintenance of the APIs you use. Some APIs may have limits on the number of requests, the data size, or the response time. Some may charge fees or require authentication. Some may change or update frequently or without notice. You should research and compare different APIs before integrating them into your app, and review their terms of service and policies.

Whatever you do, don’t build your business over someone else’s API. It’s ok to integrate competitive services (think billing or login) but to build your product’s core features relying on a single source of data/feature that cannot easily be replaced is just crazy. Just remember all the Facebook apps that have gone under or all the Apple apps, whose features are now all built into iosX…

Certainly, you should consider how difficult it will be to integrate to another API. You should consider how its built (REST, SOAP, GraphQL, etc.) and its limitations. All this is so you can forecast cost to build/support the integration and ideally compare across all of your integration opportunities. However, what you should consider most of all is what the integration means to your app's user. This is far more important than what it means for you. If you are building an integration for your app, what you are actually doing is helping a user solve a business problem or execute a business process across your and another software product. The customer's value for this should be weighed against what it costs you to build it.

Designing an app's API layer is a detailed and critical process that starts with a deep understanding of user requirements and use cases. This understanding is key to selecting the most suitable architectural style for the API, with the API-led framework standing out for its robust approach to API design. Incorporating RESTful principles is central to this process, as it ensures that API endpoints are intuitively and logically designed with clear, understandable path names. Addressing scalability is crucial, and this is achieved through a stateless design supplemented by effective caching strategies, enhancing both performance and manageability.

Implementing your app's API integration starts with a detailed analysis of requirements, ensuring the API aligns with your application's needs and use cases. Selecting the right API involves considering functionality, scalability, and documentation quality. Once chosen, understanding the API's documentation is crucial, including its request-response structure and authentication mechanisms. Setting up a development environment and ensuring secure authentication follow. The integration process includes developing and testing API calls, implementing robust error handling, and optimizing performance through caching. Continuous monitoring and logging are essential for maintaining performance and reliability.

It's important to remember that "API" does not equal "integration". APIs are the doorways for data in/out. Integrations are the data bridges between doorways. Whether custom coding (not usually recommended) or using a framework (let's talk) for the integration, the key is to operationalize the process. As an app provider you are almost certainly going to build more than one integration. Likely it will be dozens--possibly more. That means consistency in "code" is key, and that consistency is born of 1) a consistent design/develop/test process and 2) a framework that empowers consistency. Do not treat these as one-off or custom projects, because they very quickly transform into technical debt.

Successfully monitoring and supporting your integrations is key to providing the integration as a high quality product feature. Remember, as an app provider, you almost certainly have many integrations, so consistency is the key. The approach you take for building these integrations should emit logs and event traces in a common structure. In layman's terms, the integrations should all speak the same language. While technically every integration is unique, you can make sure that the ONLY part that is unique is the part that implements specific business requirements. All the plumbing under the hood can work the same. This allows anyone on the team to help support the integration, as long as they understand the common "language".

Integrations are living, breathing features. They are not build-and-forget. APIs change. Data requirements evolve. You must have a best practice process for rolling out updates to these integrations. This starts with how you've built and deployed them in the first place. Acknowledge that 1) the integration will be used by many users, likely with slightly different configurations and 2) things that have nothing to do with those users will necessitate updates. Build your integrations with a proper DevOps mindset at the start so you can roll out such changes. (Many low-code iPaaS tools ignore this part.) Treat the integrations with as much care as you would any "internal" product feature, so that you can maintain quality and uptime.

The most important things to take away are: 1) APIs are not integrations. The two are adjacent to one another and impact one another, but they are not the same thing. 2) Treat integrations with the same care as you would an internal product feature. While there are some aspects of integration that differ from an internal product feature, to your user they are just another feature. 3) Prioritize what your user needs from the integration and what value it provides them over what it costs you. Figure out the costs to serve that need. 4) Don't treat app integrations as one-offs, as side projects, or outside of your primary engineering discipline.

From my point of view, all these aspects are covered under the umbrella of API Governance. Then clearly defining how has to do what and how is definitely a must. When considering update plan for app's built on top API and how a version upgrade/downgrade can impact on the app's ecosystem affected, I would recommend sending proactively information to app devs (so they can update their app) and also provide enough information of the changes involved (tutorials, how to fix features, videos, support, and so on).