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Writer's pictureDr. Themo Voswinckel ⎪Co-Founder

How to build a custom integration right the first time


Code for API

In today's interconnected digital landscape, custom integrations are the backbone of seamless data flow between applications. Whether you're syncing internal systems or ensuring your software communicates effectively with customers' applications, nailing custom integrations from the start is crucial. But it's not always a walk in the park. From handling non-standard fields to navigating API limitations, there’s a lot to consider. Let’s dive into how to build custom integrations right, the first time and beyond.

What Is a Custom Integration?

Custom integrations are tailored solutions that sync non-standard data between applications. These can be either internal—connecting your company’s systems—or customer-facing, ensuring your software communicates with external systems. Typically built using APIs, custom integrations can also be implemented through file exchanges or even screen scraping when necessary.

Unlike standard integrations that sync common, predefined data types, custom integrations handle the unique fields and data structures that businesses need to operate efficiently. For instance, if your CRM has a “Preferred Contact Method” field that isn’t standard in your customer’s ERP system, a custom integration ensures this data is accurately transferred and used.


The Two Types of Custom Integrations

When discussing custom integrations, it’s essential to distinguish between two primary types:

  1. Internal Integrations: These are designed to connect various systems within your organization. For example, syncing data between your HRIS (Human Resource Information System) and your ATS (Applicant Tracking System) to streamline employee onboarding.

  2. Customer-Facing Integrations: These involve integrating your product with your customers' applications. A classic example is syncing customer data between your CRM and their ERP to streamline business operations like invoicing and order management.


Custom integrations are a powerful tool that can unlock significant value for your business. By understanding the types, benefits, challenges, and best practices, you can ensure that your integrations are built right the first time and continue to serve your needs as they evolve.

Custom Integration Examples

Let’s take a closer look at how custom integrations work in real-world scenarios.


Sync Custom Data Between Your HRIS and ATS

Imagine a situation where a candidate signs an offer letter in your ATS. Now, they need to be onboarded, meaning their profile must be created in your HRIS. By integrating these systems, you ensure that once a candidate is marked as “Hired” in the ATS, all relevant information—including custom fields like “Preferred First Name” or “Employee ID”—is automatically transferred to the HRIS. This reduces manual data entry and ensures consistency across systems.

Example: Custom integration between Greenhouse (ATS) and Workday (HRIS).


Sync Custom Data Between Your CRM and Customers' ERP Software

Consider a scenario where your business uses a CRM system to track sales opportunities. Once an opportunity is marked as “Closed-won,” you need to create an account in the customer’s ERP system for billing and invoicing. A custom integration ensures that all necessary fields, such as “Payment Method” and “Discount Percentage,” are accurately synced from your CRM to the customer's ERP, facilitating smooth post-sales processes.

Example: Custom integration between Salesforce (CRM) and NetSuite (ERP).


Benefits of Custom Integrations

Custom integrations are not just about connecting systems; they bring tangible business benefits that can significantly impact your operations.


Addresses Customers' Unique Syncing Requirements

Every business has its unique data and workflows. Custom integrations enable you to meet your customers where they are, syncing data that’s specific to their business processes. Whether it’s integrating with their proprietary systems or syncing unique fields like “VIP Customer” or “Loyalty Status,” custom integrations make it possible.


Empowers Your Employees to Perform Better

For internal teams, custom integrations provide critical data that can be used to make smarter decisions. Sales teams, for example, can access personalized lead information directly in the CRM, while customer support teams benefit from detailed ticket data, leading to quicker resolutions and happier customers.


Unlocks Improved Business Outcomes

When employees have access to the right data at the right time, they can work more efficiently. For instance, sales reps with detailed lead data can tailor their pitches, resulting in higher conversion rates. Similarly, support teams can resolve issues faster with comprehensive ticket details, boosting customer satisfaction.


Challenges of Custom Integrations

While the benefits of custom integrations are clear, they’re not without their challenges. Here are some common obstacles you might encounter:


Mapping Custom Fields Can Be Difficult

One of the primary challenges in custom integrations is mapping fields between systems, especially when the fields don’t directly correspond. For instance, a field labeled “Preferred First Name” in one system might not have an equivalent in another, requiring the creation of new fields and coordination across departments to ensure accurate data transfer.


API Providers Can Limit Custom Field Syncing

APIs are a common method for building integrations, but they come with limitations. Some API providers restrict access to only standard fields, making it difficult to sync custom data. In such cases, you might have to resort to alternative methods like file-based integrations or screen scraping, both of which have their drawbacks, including delayed syncing and maintenance challenges.


Complex Data Transformation Logic Is Often Required

Data transformation is often necessary to ensure that the data being transferred is in a format that the receiving system can understand. This process can be complex, requiring significant engineering resources and time. For example, transforming date formats or converting currency fields might seem straightforward but can become complex when dealing with multiple systems and data types.


Best Practices for Building Custom Integrations

Given the challenges, how can you ensure your custom integrations are successful? Here are some best practices to follow:


1. Thoroughly Understand the Requirements

Before diving into development, make sure you thoroughly understand the integration requirements. What data needs to be synced? Are there any custom fields? What are the constraints of the APIs involved? Document everything.


2. Start with a Pilot Project

If possible, start with a smaller pilot project to test the waters. This approach allows you to identify potential issues early on without the risk associated with a full-scale implementation.


3. Use a Modular Approach

Design your integration in a modular fashion. This way, if one part of the integration needs to be updated or replaced, it won’t disrupt the entire system. A modular approach also makes testing and debugging easier.


4. Monitor and Maintain

Custom integrations aren’t a set-it-and-forget-it solution. Ongoing monitoring and maintenance are essential to ensure they continue to function as intended. Set up alerts for any errors or issues, and regularly review the integration to see if it needs updating as your systems evolve.


5. Leverage Tools and Platforms

Consider using tools or platforms designed for building and managing custom integrations. For instance, Maesn offers a unified API solution that simplifies the process by providing features like Field Mapping and Authenticated Passthrough Requests. These tools can save you time and reduce the complexity of your integrations.


Leverage tools like Maesn for Custom Integration Solutions

If building custom integrations sounds daunting, tools like Maesn can help simplify the process. Maesn provides a unified API solution that allows you to:

  • Use Field Mapping to add and sync additional fields across systems.

  • Access and sync custom fields in their original format with Remote Data.

  • Make API requests to access custom data using Authenticated Passthrough Request.

With Maesn, you can build robust custom integrations tailored to your specific needs, without the headaches typically associated with such projects.


Custom Integration FAQs


What Is the Difference Between Standard and Custom Integrations?

Standard integrations sync common data types provided by SaaS applications out of the box, while custom integrations handle unique data types that you or your customers have defined.


How Are Out-of-the-Box Integrations Different from Custom Integrations?

Out-of-the-box integrations offer prebuilt functionality, making them quicker to implement but less flexible. Custom integrations, on the other hand, are built from the ground up, providing flexibility to meet specific needs.


How Does a Custom API Differ from a Standard API?

A custom API is designed to meet the specific needs of particular API consumers, offering endpoints tailored to their requirements. A standard API, however, is more generic, designed to accommodate a wide range of consumers and use cases.

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