10 Crucial Points to Consider while Developing App APIs

Top Crucial Points to Consider while Developing App APIs

An app without a back-end can easily become limited and outdated. This is the reason a majority of apps rely on one or more back-end services – third party, legacy systems, or new app-specific functionality. The performance of APIs can greatly affect user experience. APIs gone wrong may lead to app crashes or stalls, resulting in bad user experience, app uninstalls, and negative reviews. Hence, APIs play a crucial role in getting positive or negative reviews on your application.

Planning for thorough API engineering should be done from the start of the software development lifecycle (SDLC) to ensure your app runs smoothly. So where to start? Check out the key things that you must know while developing an app API.

1. Select Explanatory API URL Endpoints

You need to design clear and accurate API URL endpoints to ensure the development team is able to understand the resources. For instance, if the API is meant for the snacks industry, then some of the resources can be chips, a brand, and a user. Hence, you may construct your APIs as follows:

GET → /chips

POST → /chips

GET → /chips/{chipsId}

PUT → /chips/{chipsId}

PATCH → /chips/{chipsId}

DELETE → /chips/{chipsId}

GET → /chips/{chipsId}/brand

GET → /users/{userId}

GET → /users/{userId}/favoriteChips

This pattern easily reflects what is present in the resource. All HTTP verbs describe the actions that endpoints are supposed to perform. It is crucial to keep a certain pattern to ensure efficient organization of all the endpoints.

Let us take a look at endpoints that you shouldn’t make:

/getChips

/createNewChips

/addChipsToFavorite

/addNewUser

/returnChips/{beerId}

At first glance, you might find these endpoints clear. However, APIs with these endpoints might frustrate developers because all of them will require a new endpoint for every action. It can be confusing and difficult to create a new endpoint.

2. Do Not Reinvent (RESTful API) Architecture

The heavily used API architecture style is RESTful (Representational State Transfer). REST APIs leverage HTTP requests to perform various actions including PUT, POST, GET, DELETE, and PATCH. It is ideal for app APIs because they are easy to implement and lightweight. You can also leverage a lot of testing and development tools to implement it.

3. Let the Server Do the Heavy Lifting

Mobile devices have a limited amount of computing resources. But the computing ability on the back end is gigantic and robust; especially on large servers farms of AWS and Azure. Hence, few operations that you can do client-side can be done on the back-end for maximum efficiency and reliability. On top of that, the back-end is also nearer to the location where data is stored in comparison to a mobile that can be present in any part of the world. Querying and data processing on the server-side are more efficient with respect to the client making API calls to fetch the data.

4. Create Versions of Your App APIs

To handle multiple versions of an app, your servers need to handle and consolidate multiple requests from legacy and new users simultaneously. However, you can’t always push software updates for all users. Hence, APIs should be able to handle requests from multiple app versions.

Here is how the endpoint would look:

GET → /v1/chips

GET → /v2/chips

5. Prioritize Performance and Scalability

With an increased response time of APIs, the user also waits for the delayed action on the app. It can be frustrating for an app user and might attract negative reviews and disrepute the business. Hence, it is business-critical to measure the response time of all the endpoints.

Even when the APIs are responding as per expectations during individual testing, you should consider the possibility of thousands of users using the app simultaneously at any point in time. In such scenarios, consider technologies and architectures that can help you build a scalable app – including serverless architectures, microservices, autoscaling services, and orchestrators like Docker Swarm, Kubemetes, and more.

6. Use Three Back-end Environments

An app goes through various updates throughout its lifecycle. Each phase has a unique software version and purpose. While you develop new features, other features may be under QA or production. Make sure the one development phase is not interfering with another during the app lifecycle. It is advisable to follow the best practices of commercial quality software development. You should also leverage three back-end environments including development, staging, and production. Create a process to migrate from one environment to another and also rollback in case of a business-critical issue.

7. Leverage Standard Security Protocols and User Authentication

Requests traveling through the internet always pass through public servers and routers. The majority of them are secure but you can’t rely on all of them. There is always a threat to altered responses and capturing of sensitive data like personal ID and financial transaction information. To safeguard your app against such cases, you should use tried and tested authentication protocols and encryption technologies.

Always have HTTPS in the back-end to secure your data. If app API supports user authentication, then you should use standard protocols including OPENID and OAUTH. You can also use Sign In with Apple or Google to eliminate the need for users to register a unique account on your app.

8. Allow Data to Select the Database

While developing the back-end, you choose from two major database technologies including document database and relational database. Relational database helps in having more standardized data with advanced capabilities for data query and predefined schemas. However, one of the major disadvantages is tables are locked until the completion of a transaction during the data update. This makes it difficult to scale up your app.

Document databases are relatively more flexible because the data is stored in a complex structure and can be as complex as you want. You can upgrade these documents easily without blocking actions. Hence, it is easily scalable and you can also distribute it globally.

Cloud databases also work similarly as traditional document databases. However, it is provided by cloud vendors. You can scale and distribute data globally through a few simple clicks. You consider this type of data for a serverless app.

9. API Responses Should Be Efficient

You may have heaps of data stored in the back-end database in the future. Hence, while making calls to API, there can be several results to return. It can increase the computational costs to retrieve, transfer, and consume the data. On top of that, the app can become less responsive as the number of users increases. To fix these issues, you need to paginate results. 

And your app will become less responsive as you add more users. This isn’t good! To fix this, you’ll need to paginate the results. Choose a method including LHS brackets, RHS colon, more to filter, sort, and paginate APIs. Whatever method you choose, be consistent with it.

10. API Responses Should Be Clear

Be consistent and clear while creating API responses. You can leverage standard HTTP status codes including 204, 202, and 200 for 4XX errors and success responses. It is advisable to not mix “snake_case, “camelCase, or “PascalCase” for JSON keys. You can use any formatting but should be consistent.

Be careful with time and date. You can accept and send dates with the UTC value in ISO 8601 format. You should not rely on the server to pick the time zone or its display format. Mobile app clients should be allowed to decide the display format on the basis of device settings for language and region, as you would often have global users using your app. 

In Summary

With evolving market requirements, app development has become more challenging. App APIs play a crucial role in deciding the end-user performance of any mobile application. Above mentioned points can help you create flawless app APIs.

QA InfoTech offers end-to-end app development solutions for both iOS and Android. You can connect with our mobile app experts to explore the possibilities of app development for your business.

About the Author

QA InfoTech

QA InfoTech

Established in 2003, with less than five testing experts, QA InfoTech has grown leaps and bounds with three QA Centers of Excellence globally; two of which are located in the hub of IT activity in India, Noida, and the other, our affiliate QA InfoTech Inc Michigan USA. In 2010 and 2011, QA InfoTech has been ranked in the top 100 places to work for in India.

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