What is API Integration | A guide to APIs

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In this definitive guide, we aim to streamline your understanding of what is API integration, covering all aspects from different types of APIs, authentication procedures, reading and writing functionalities, deployment, monitoring, and scheduling. We'll also delve into the integration process with third-party APIs, providing you with the tools you need to further enhance your software development workflows.

What is an API?

API is an acronym for Application Programming Interface. Essentially, an API is a conduit that facilitates the interaction between various applications, systems, and SaaS solutions through a unified ecosystem. Currently, virtually every platform provides an API to streamline repetitive workflows, enabling the creation of superior customer experiences. This automation functionality is a core aspect of modern software development, and is a key component in the digital transformation of business processes.Understanding the functionality of APIs, or Application Programming Interfaces, is crucial as they facilitate seamless data transfer between different applications, thereby automating business processes. APIs work by managing communication with separate software applications and processing API requests from external clients. An API integration consists of two components: the server, which holds the resources or data, and the client which accesses this information. APIs create an ecosystem of rules that dictate how the client and the server interact to execute specific tasks, streamline workflows, and enhance user experience. This definitive guide to the benefits of API integration helps to understand the integration process and the role of APIs in digital transformation.

The Types of APIs

We can primarily categorize APIs into four different types - REST (Representational State Transfer), GraphQL, SOAP (Simple Object Access Protocol), and RPC (Remote Procedural Call).


Representational State Transfer (REST) APIs excel in data transfer from a server to different applications. There's a definite separation between the two entities as the client initiates an API request and, in response, the server generates an answer. For optimum functionality and compatibility, all API requests and responses must adhere to the HTTP protocol, and responses are formulated in JSON format.

The communication between both parties in REST APIs, or Representational State Transfer APIs, is stateless, meaning the server does not retain any context between two API requests. The design of these types of APIs is such that neither the client nor the server can discern if they are interacting directly with the end application or with an intermediary layer, such as an API gateway or load balancer. In line with general best practices, all REST APIs exhibit a layered architecture, streamlining the integration process by ensuring the client and server engage with multiple intermediary layers during the data exchange loop. To enhance performance and user experience, resources in REST APIs are made cacheable.


GraphQL is an open-source data query and manipulation language for APIs, simplifying the process of combining data from different applications.Unlike REST API, or representational state transfer, GraphQL allows clients to define the structure of the responses to their API requests. This level of customization allows clients to ask for exactly what they need, making it an ideal tool for crafting custom integrations. GraphQL APIs provide a high level of scalability, crucial for businesses undergoing digital transformation. As your business expands, GraphQL grows with you, equipping you with the necessary tools to manage this growth effectively.


Simple Object Access Protocol (SOAP) APIs are primarily geared towards facilitating highly secure data transfers within a system. Originating in the 1990s, the SOAP framework outlines the method of message transmission and the types of resources to be encapsulated within these messages. While they offer superior security compared to Representational State Transfer (REST) APIs, SOAP APIs demand more code and present a higher level of difficulty during implementation. XML is the standard format for encoding information in all SOAP APIs. A definitive advantage of such types of APIs is their ability to function over any communication protocol, moving beyond the limitations of just HTTP.


RPC APIs, leveraging both JSON and XML formats, facilitate the execution of scripts on a server. Primarily, they serve internal systems and remote services or networks. Unlike other types of APIs that emphasize data transfer, RPC APIs initiate processes and actions. This functionality, a key aspect of API integration, allows for automation and streamlining of workflows within the software development ecosystem. This real-time application programming interface (API) integration enhances the efficiency of different applications, positively influencing the user experience and customer experience.

What is API Integration?

APIs exhibit different characteristics, and to leverage their functionality, you initially require API integration to interlink your different applications. In essence, an API acts as an access point, while API integration serves as a conduit connecting this access point to others. API integrations streamline your business processes and ensure real-time data synchronization, effectively meeting your business needs. However, API integration poses a challenge as it demands the adoption of a ready-made solution or hiring a software development professional to create custom integrations for every SaaS tool or system in your data ecosystem. This task can be daunting due to the multitude of factors that need consideration.

Understanding the API Interface

Initiating integration with a third-party API and developing a custom integration application begins with thoroughly understanding the API's endpoints. This task can often be more challenging than it appears. An effective starting point is to consult the documentation provided by the third-party service. Ideally, this documentation should include numerous well-explained examples of endpoints and return values, detailed descriptions of rate limits, and straightforward authentication procedures. However, in less ideal situations, much of the process may involve trial and error as you navigate your way through understanding the API's functionality.

It's advisable to create a test account and prepare some sample data for API testing, which involves both reading from and writing to the integration. While many applications offer a trial account sufficient for initial steps, others might require a paid subscription or even discussions with a sales representative to begin.

Tools for API integration, such as Postman or Insomnia, are beneficial for organizing endpoints and simplifying authentication by managing cookies and headers. Documenting API requests and responses early on will significantly ease the development phase once it commences.

You can use API testing tools such Postman, Hoppscotch, cURL, etc.

Authenticating the API

Once you've acquired a fundamental comprehension of the application programming interface (API), your immediate interest will likely be in comprehending the authentication process. Certain types of APIs function with a straightforward API token, like a Bearer Token, which is given in the headers.

Different software applications may boast more intricate automated business processes. By leveraging OAuth for authentication, particular permissions can be conferred to specific resources. This API integration process might yield tokens that maintain their validity for a set duration and necessitate periodic refreshing. These are critical aspects of how APIs work, allowing for real-time data exchange and enhancing the overall user experience.

For optimum functionality and streamlined workflows in software development, it is recommended to fetch secrets from the environment rather than embedding them directly into the application programming interface (API) configuration. This API integration practice enhances the scalability and automation of business processes, making it a vital part of digital transformation. An effective integration process may involve maintaining separate accounts for development and production usage, thus catering to different applications and business needs. This method not only enhances data integration but also improves the overall user and customer experience. It's an essential part of API management and a definitive guide to how APIs work.In more intricate software applications, it could be beneficial to let the user configure their own API keys, given their tendency to alter frequently. Certain security protocols could necessitate the regular modification of such access control tokens.

Reading From and Writing to the API

The majority of APIs typically adhere to a REST API, or representational state transfer interface, where data can be pulled or "get" using an HTTP get request. Conversely, data updates can be accomplished via POST, PATCH, and PUT methods - all types of APIs. During the data transfer process, JSON stands out as a frequently used format for transmitting information.REST API Integration using JSONDepending on the software development language used, you may need to utilize API requests, such as GET or PUT, for data transfer. Numerous APIs, including REST API and GraphQL, paginate data to prevent excessively large payloads. For such APIs, you typically receive a URL or page number as part of the response from the endpoints. However, in some cases, you may need to navigate through the pages using different types of APIs until there is no data returned. This part of the API integration process may involve the use of API keys for authentication and may be affected by rate limiting, depending on the API management policy of the providers.In certain instances, client libraries may be accessible for your software applications. Python and Java are frequently encountered, but there are occasions where JavaScript may also be used. For more extensive applications, client libraries may be offered in several different types of APIs, but for many smaller APIs, you may need to undertake the integration process of creating your custom integrations.API Integration with Third-Party Applications

Querying Source Data

When executing an API integration with another system, it's imperative to determine how to manage your data transfer and query processes. One method involves the functionality of an event-based system. This system responds to particular actions within your software applications. For instance, an 'UserCreated' event may activate your integration process, prompting it to register the newly created user into the different applications of the third-party system. While this approach is simple to configure, event-based models do present challenges. They are primarily limited in tracking real-time updates such as changes in names or emails, and stumble in specific use cases like data migrations.Instead of making direct queries from your database or data storage, utilizing API integration might prove to be a more efficient strategy. The functionality of change-data-capture can offer a real-time stream of database modifications, allowing for seamless synchronization with the third-party application. Employing batch jobs using Python can facilitate the data transfer of entire datasets. However, more advanced systems might monitor changes, permitting only new or updated data to be sent. This process streamlines the integration process by reducing the volume of API requests, enhancing the scalability of the API integration platforms. This approach, in turn, leads to more effective automation of business processes and improved customer experience.

Fetching Destination Data

In certain scenarios, you may require to execute a 'get' action to retrieve data before you can input or 'put' it back. For instance, in your initial data, there might be a team member handling the customer experience with a specific contact. However, your third-party application programming interface (API) may not permit you to delegate ownership of contacts via name or email. Instead, it only allows this through an internal ID. In such a case, you would first need to use the 'get' functionality to call up the list of owners from the API integration platform and then fetch the necessary ID by finding a match with the email. Once you have the ID, you can then 'put' it back into the system with the owner, completing the data transfer. This is a crucial aspect of the API integration process, demonstrating how APIs work to streamline workflows and enhance real-time data exchange in different applications.

Establishing connections can often be a complex aspect of the integration process, hence the importance of not making assumptions about the integrity of the incoming data. For instance, you might perceive emails as unique within the API integration, but this might not always be the case. Therefore, the functionality of matching them in the data transfer process needs to be executed with caution, ensuring optimal customer experience. This careful approach is one of the many benefits of API integration in software development.

Mapping Fields

To execute data transfer from one point to another, a form of mapping is necessary to correlate the field names in the source to those in the destination. For instance, a field termed 'user_email' in your source database might be referred to as 'ContactEmail' in the destination. While it might be tempting to hard-code these for a small number of fields, it's recommended to configure these field mappings due to the likelihood of evolving business needs and the expanding data requirements for API integration in the future. Being able to bypass a code modification each time a field alters can streamline the response time to business needs. Dynamic field mapping offers a practical solution to prevent typographical errors that could lead to corrupted data. This functionality contributes to the efficiency of the integration process, enhancing the overall user experience and customer experience in data integration.This approach also adds to the scalability of your system, as it can adapt to different applications and types of APIs, whether it's a REST API, JSON, or others. It also simplifies the management of APIs, making it an essential part of digital transformation and improving business processes. So, using API integration tools like Zapier, Salesforce, or others for this purpose can be beneficial.

Rate Limits, Batching, and Parallelizing

Numerous APIs frequently impose rate limiting, dictating the maximum quantity of API requests one can make to a designated endpoint. This often prompts the utilization of a Batch API over event-centered ones, particularly for extensive workflows. Achieving the right balance with rate limiting can pose a challenge, as your software applications may exhibit slower responses during the development stage compared to the real-time functionality in production.Managing rate limiting effectively can be achieved by leveraging fixed-size batches. The principle here is simple: the larger your batches, the fewer API requests you'll need to make. However, be mindful when dealing with larger batches, as many APIs - in their quest to streamline data transfer and improve the user experience - also impose restrictions on the amount of data that can be sent in a single request. Being able to configure the batch size to find the perfect balance between the number of calls and the size of data can be a vital part of your API integration process. So, it's essential to understand how APIs work and the different types of APIs available. This will be your definitive guide to effective API management, contributing to your overall digital transformation strategy.Often, but not always, you may encounter a 429 HTTP status code in the API integration process, indicating too many API requests. Typically, the header of this response includes a Retry-After, providing essential data transfer information such as when to attempt the next request. If this is missing, it might be beneficial to retry using an exponential back-off strategy in your application programming interface, optimistically anticipating that the request will eventually be successful if you wait sufficiently. Configuring the back-off and the maximum number of retries can be somewhat experimental and will largely depend on the specific endpoint you are writing to. This is a key aspect of API management, enabling efficient real-time interaction between different applications and enhancing the overall user experience.

In certain ecosystems, the functionality of your system could greatly benefit from the automation of parallelized API requests. Numerous types of APIs do not impose rate limiting that would hinder your data transfer processes. However, certain APIs work at a pace that may not meet your business needs in real-time. To streamline this process, you can break your data into batches, sending multiple batches simultaneously to the same endpoint using API integration. This method can potentially improve the time efficiency of writing data to the end systems in your software applications. It is one of the benefits of API integration that helps in enhancing the user experience and customer experience. The API integration tools and API management tools can monitor this integration process and ensure the scalability of your workflows.

Handling Errors

Various issues can arise during the integration process when writing to third-party software applications, including network problems. These could result in the system either not receiving your API requests, or it might receive them but fail to provide a successful response. If your systems are designed with idempotency, the functionality to reattempt the process is a viable solution. However, if this isn't the case, it's crucial to carefully consider how to manage retries for different types of APIs, especially when encountering errors. This is a definitive guide to understanding how APIs work and streamlining your workflows through effective API integration, enhancing the overall user experience and optimizing business processes.Commonly, issues can arise from the API integration itself. Certain types of APIs use HTTP status codes to signal specific errors, while others, such as GraphQL, might return a successful status but include error details within the response. If the third-party API documentation is well-crafted, these errors will be comprehensively explained, enabling you to devise functionality for managing them. Otherwise, you may consider sending invalid data and API requests to gauge how the system handles errors. This preemptive approach is advantageous as it uncovers potential pitfalls before they become significant problems.Mistakes can happen at the overall request level or on a row-by-row basis. For instance, Salesforce might produce errors for a batch of API requests, where certain rows are unsuccessful while others are triumphant. Revealing row-specific errors can be beneficial for users to troubleshoot problems or to discern when issues can be disregarded safely. This is an integral part of API integration functionality and a key aspect of improving the user experience while using different types of APIs. It's also part of the API management process that can be streamlined using API integration tools. This is a practical example of how APIs work and the benefits of API integration in software development.Determining the different types of APIs errors can be a challenging task, yet it's crucial for the enhancement of the user experience. Some errors in the API integration process can be rectified through a simple retry, while others may require more comprehensive solutions. Ensuring these relevant errors are visible to the users of your software applications can streamline the debugging workflow and provide more real-time observability into the system's functionality.For instance, changes in permissions might be causing issues within your application. If the business user needs to activate a new set of permissions, being able to expose that error within your application in a user-friendly manner can simplify their tasks. This could potentially prevent issues from escalating to the software development team, therefore improving the overall customer experience and promoting efficient business processes.API management tools and API integration platforms play a vital role in this process, ensuring the smooth data transfer and enhancing the API integration's functionality. The definitive guide to handling API requests would be to configure the system to effectively communicate errors, making it easier for users to address them without needing to understand complex technical details. This is an essential aspect of digital transformation, offering numerous benefits of API integration, including enhanced automation and scalability.

Logging your progress

Maintaining comprehensive api request logs is an often underestimated aspect of software development, one that becomes crucial only when issues arise. API integration tools allow for robust logging of requests and responses, enhancing the functionality of your system, and providing a valuable resource for debugging potential problems. For instance, if data is absent from a target application, locating the primary key within the logs can help determine whether the API request was ever initiated and if it was successfully executed. This can assist in pinpointing where the breakdown in the data transfer occurred in the integration process. Implementing such meticulous logging strategies can streamline workflows, enhance the user experience, and contribute to the overall automation and scalability of the business processes.Monitoring through logging can enhance the user experience by providing real-time updates on the progress of active data integrations, particularly during lengthy API integration processes. By capturing timestamps during the different steps of the integration process, it becomes easier to profile and understand the duration of API requests, enhancing the functionality of the application programming interface. This level of automation in monitoring can aid in identifying potential issues before they escalate, thus streamlining workflows in the business processes. It's a crucial aspect of API management, that not only ensures seamless data transfer but also contributes to the overall digital transformation of your business.

Deploying integrations

Upon completing the software development of your custom integrations, the subsequent phase involves identifying a suitable deployment method. The choice of method may vary depending on the different types of APIs used in building your application.

For event-driven custom integrations, leveraging lambdas can be an effective starting point due to their real-time response to individual events before termination. Most cloud lambdas can be configured to read from a message bus or queue, a functionality that streamlines the integration process and provides scalability. This means you can easily amplify your API integration to meet increased business needs or scale it down when the load is reduced. This is a key benefit of API integration in the digital transformation journey, enhancing efficiency in data transfer and improving the overall user experience.To handle batch-processing, you may find it beneficial to utilize orchestration tools such as Airflow, Dagster, and Prefect. These software applications can be configured to operate on an hourly or daily basis, offering the functionality of recording application programming interface (API) output for logging. They also possess built-in features for retrying in the event of failures. Such tools can streamline your workflows, enhancing the efficiency of your data integration process. This is part of the digital transformation brought about by the use of API integration tools, which serve as an essential component in the world of software development.If your business needs advanced functionality, contemplating an entire application deployment might be advantageous, potentially benefiting from microservices containerization. As your business processes adapt, gaining more precise control over scheduling and workflows may become desirable. However, bear in mind, even a basic scheduler in software development can be challenging to get right. Reflect, for instance, on what transpires if your application's run time exceeds the interval between schedules, or if there's a need to backfill data post a fix. These scenarios can be complex to manage correctly and it's often more efficient to utilize an integration solution that already has these edge cases addressed. This is particularly crucial when dealing with different types of APIs and when working with real-time data transfer. Remember, API integration, whether it's REST API or GraphQL, can streamline this process. API management tools, like Zapier or Salesforce, can handle these issues, providing scalability and improving the customer experience. API keys and OAuth authentication also play a significant role in secure API integration. By using API integration platforms, businesses can meet their unique needs, ensuring seamless data exchange between different applications. So, consider the benefits of API integration for your digital transformation journey.

Monitoring integrations

Monitoring the progress of your API integrations is vital to confirm their optimal functionality. Apart from having access to logs, exposing metrics on the API integration processes themselves may be beneficial. Useful high-level metrics could include the total rows queried in the source, the total operations executed on the destination, and the real-time duration for query and write completions. For a more detailed analysis, you might want to disaggregate this data based on types of API operations, such as adding a new data row versus updating an existing one. This process is a crucial part of API management, allowing you to streamline workflows and improve the efficiency of data transfer in your business processes.Making the choice on how to display these metrics relies on specific use cases. Certain teams utilize management tools such as Datadog to oversee their infrastructure. By configuring these metrics to a Datadog instance, you can swiftly establish summary dashboards and even create monitors that alert when particular thresholds are surpassed. This functionality is part of the digital transformation process, enhancing the user experience with real-time data exchange and automation.

Alerting is a critical functionality in the realm of API integration. If there is a system failure but no active monitoring in place, an outage can easily be overlooked. Hence, having the capability to trigger alerts when an integration process breaks down, or when a certain number of rows fail to write as expected, is crucial for maintaining the health of your data transfer pipeline. Instant messaging platforms like Slack are commonly utilized for real-time alerting, but in some use cases, tools such as PagerDuty may also offer valuable benefits of API integration.The capability to customize alerts for different types of APIs can be crucial in averting notification overload, particularly for those API integrations that are more vital to business processes. This functionality forms an important part of the API integration process, optimizing the user experience and streamlining workflows.

Wrapping Up

As apparent, constructing API integrations may seem straightforward initially, but the underlying intricacies involved in data transfer among different applications imply that there are numerous factors and compromises to contemplate. The process of integration, which is essential for automation and enhancing functionality, involves the use of various types of APIs, including REST API and GraphQL. However, API integration does come with its challenges. Issues like permissions, headers, and the use of open-source versus proprietary software can significantly impact the functionality and user experience. Therefore, it is essential to choose an integration solution that best suits the business's unique needs and workflows, and helps in achieving digital transformation effectively.

December 31, 2023
Pradeep Sharma

Pradeep Sharma

Developer Relations