APIs and Legacy Modernization: Strategies from Your API Developer

You’ve probably used your Facebook or Google login credentials to log into another web application. It seems simple enough, but this kind of convenience is made possible by an in-depth technological connection: an Application Programming Interface, or API.

APIs are indispensable tools for today’s companies — particularly those using legacy systems. Legacy systems often lack the flexibility needed to meet modern demands, but many companies still rely on them because they form the backbone of their operations. If your company is relying on a legacy system, replacing it entirely might not be a feasible option. Modernizing it, however, is entirely possible thanks to APIs.

APIs enable your organization to enhance the functionality of existing infrastructure while setting the stage for future innovations. By building APIs on top of legacy systems, your company can achieve great agility, streamline operations, and facilitate seamless data exchange across diverse platforms.

But what is an API, exactly, and what is the role of an API developer in API design and implementation? What kind of API approach will work best for your company’s purposes?

APIs 101: What Is an API?

An Application Programming Interface, or API, serves as a bridge between different software applications, enabling them to communicate, exchange data, and leverage each other’s functionality seamlessly. Think of it as a set of rules and protocols that dictates how software components interact with one another. (We’ll take a look at some examples in just a moment.)

In practical terms, APIs simplify the complexities of software development by allowing API developers to integrate pre-existing services and functionalities into applications, without having to build everything from scratch. This accelerates development cycles and also enhances the capabilities of applications by tapping into a broader ecosystem of services.

One of the main advantages of using APIs lies in their ability to facilitate controlled access to application resources. By defining specific endpoints (the “connection points” where APIs send requests and where the resource is) and methods of interaction, data and sensitive information can stay secure and safeguarded. This is important for enhancing system security and minimizing vulnerabilities; access is restricted to only what is essential for specific operations or integrations.

API Examples

If you’re not an API developer yourself, it can be easier to understand APIs through real-world examples. Here are three example use cases:

• Weather app: A weather application on an iOS or Android mobile operating system fetches real-time weather data from a weather service provider’s API (the National Weather Service, for example). The API delivers current conditions, forecasts, and relevant meteorological information to the app, ensuring users receive the most up-to-date weather reports.
• SaaS integration: Software as a Service (SaaS) is an area in which APIs are used quite frequently. For example: A customer relationship management (CRM) software platform integrates with a third-party email marketing service through an API. The CRM software relies on the API to sync customer contact information, segmentation data, and campaign analytics, allowing for more efficient customer interactions without synchronization errors.

• Social media: A job recruitment platform (Indeed, for instance) integrates with LinkedIn through an API. The API calls on LinkedIn to fetch employment histories and skill endorsements of candidates, allowing the recruiter to streamline candidate sourcing without having to seek out every candidates’ individual profile manually.

Or, take a legacy API upgrade as an example. When Hertz partnered with Uber and Lyft, it revealed a 30-year technology gap between the companies. Hertz’s old system was upgraded with a newly designed API, which now serves more than a million requests daily — and generates more than $100 million per year.

4 Common API Protocols

Originally, APIs were tied to specific programming languages; namely, the web-browser language of JavaScript. Now, APIs are predominantly built on HTTP. This allows for universal accessibility and easy integration across most of today’s most popular programming languages — Java, Ruby, Python, and PHP, for example.

With the rise of web APIs, API developers have come up with protocols and standards to help streamline and formalize the exchange of information. Some are more commonly used in legacy system environments, while others are more modern.

Let’s take a closer look at four common API development tools: SOAP, RPC, REST, and GraphQL.

SOAP

SOAP, or Simple Object Access Protocol, is a foundational protocol for exchanging structured information in the web services ecosystem. It utilizes XML (Extensible Markup Language) to format its messages, providing a standardized approach to communication between client and server applications.

SOAP was more popular in past years than it is now, but it remains relevant in enterprise environments where strict messaging protocols and security are important. As such, many companies still relying on legacy infrastructure use SOAP APIs.

RPC

Remote Procedure Call (RPC) is another older API protocol, but it’s still relatively common among legacy enterprises because of its simplicity, lightweight operation, and scalability.

RPC streamlines the interaction between distributed applications by simplifying the complexities of network communication. It lets an API developer complete a function on a remote server and receive results as if the function call were local. This allows for seamless integration and operation across environments and programming languages.

There are several variants of the RPC protocol:

• XML-RPC utilizes XML as its message format for data transfer. It’s suitable for applications where bandwidth efficiency is crucial. Despite being older than even the SOAP protocol, XML-RPC remains straightforward and effective for basic RPC needs.
• JSON-RPC employs JSON (JavaScript Object Notation) for its data interchange format. Widely recognized for its simplicity, readability, and ease of parsing across various programming languages, JSON-RPC is ideal for applications that require fast and efficient data exchange.
• gRPC is a modern and high-performance RPC framework developed by Google. It uses HTTP/2 as its network protocol for transport and Protocol Buffers (protobuf) as its data serialization format. gRPC is designed for building efficient and scalable distributed systems, particularly in microservices architectures where low latency and high throughput are critical.

REST

REST stands for Representational State Transfer. This is a more modern and widely used architectural style for designing networked applications and APIs.

REST APIs — also called RESTful APIs — treat every piece of data or functionality as a resource identified by a unique Uniform Resource Identifier, or URI. Clients interact with these resources through standard HTTP methods such as GET, POST, PUT, PATCH, and DELETE. For example, a client application can retrieve data from a server using a GET request to a specific URI representing the resource.

In plain English, REST sees everything (like data or actions) as something you can find using a special web address. When you want to do something with that data or action, like read or change it, you can use a standard command to do it.

One of the defining characteristics of RESTful APIs is what API developers call “statelessness.” This means that each request from a client to a server must contain all the information necessary to understand and fulfill that request. The server does not store any client context between requests, enhancing scalability and simplifying server implementation. Statelessness fosters a reliable and predictable interaction model where each request is self-contained and independent of previous requests.

REST APIs are widely favored for their simplicity, scalability, and flexibility in web service development. They promote loose coupling between client and server, allowing for the evolution and modification of server-side functionality — without impacting clients.

GraphQL

GraphQL is a query language tailored specifically for fetching data. First developed internally by Facebook in 2012, and later released as open-source in 2015, GraphQL prioritizes efficiency and flexibility in data retrieval and streamlines interactions between front-end applications and backend services.

Unlike REST, where multiple endpoints might be required to fetch data, GraphQL consolidates these queries into a single endpoint. This lets API developers fetch data from multiple databases, microservices, or APIs while reducing the number of requests and simplifying application architecture.

The Benefits of REST and GraphQL

Both REST and GraphQL offer unique advantages that cater to different application development needs and workflows, and an experienced API developer may recommend one or the other for your company’s needs:

• REST is widely used for web API development thanks to its simplicity, scalability, and adherence to HTTP standards. Its stateless architecture ensures reliability throughout the application lifecycle, and it’s also one of the most scalable APIs. By adhering to uniform interface constraints and standardized HTTP methods, REST enhances predictability and separates client-server concerns, making REST APIs ideal for a wide range of applications.
• GraphQL offers a query language that allows users to request precisely the data they need. Because GraphQL consolidates queries into a single endpoint, over-fetching or under-fetching of data is reduced, making this protocol ideal for applications requiring flexible data-fetching capabilities. And because GraphQL provides a clear and comprehensive description of the API’s capabilities, it allows front-end developers to iterate quickly without being constrained by back-end development changes.

Leveraging REST or GraphQL — or both — in your company’s API strategy can provide a balanced approach to address your application requirements. REST offers reliability and familiarity, while GraphQL excels in dynamic and data-intensive applications. Your API developer will understand the strengths of both and can help you choose between or even combine the two, allowing you to optimize API performance and user experience across different use cases.

Tackle Digital Transformation with Seasoned API Developers

If your company is operating on a legacy infrastructure and you want to modernize your systems, or if you simply need two systems to be able to “talk” to one another, the technical skills of experienced API developers are invaluable. They can help you decide what kind of protocol — REST, GraphQL, RPC, etc. — will work best for your needs, and assist with design and implementation to ensure successful results.

Focused Labs’ technology consultants can help your company navigate legacy modernization and digital transformation, including legacy API upgrades. Our incremental modernization model means you aren’t reliant on our team once we’ve handed over the reins.

To get started, contact the Focused Labs team.