A Glossary of Key Integration & API Concepts for HR Tech Stacks

In today’s fast-paced talent landscape, HR and recruiting professionals rely on a diverse tech stack to streamline operations, enhance candidate experience, and make data-driven decisions. However, the true power of these tools is unleashed when they can communicate seamlessly. Understanding the core concepts of integration and APIs is no longer just for IT departments; it’s a critical skill for anyone looking to optimize their HR tech. This glossary defines essential terms, explaining their relevance and practical application in building a cohesive, automated HR environment.

API (Application Programming Interface)

An API serves as a set of rules and protocols that allow different software applications to communicate and exchange data. Think of it as a waiter in a restaurant: you (the application) tell the waiter what you want (a request), the waiter goes to the kitchen (the server), retrieves your order (the data), and brings it back to you. In HR, APIs enable systems like your Applicant Tracking System (ATS) to pull candidate data from a job board, or your HRIS to send new hire information to a payroll system, eliminating manual data entry and ensuring consistency across platforms. Leveraging APIs is fundamental to creating integrated and automated HR workflows, saving significant time and reducing errors.

Webhook

A webhook is an automated message sent from an application when a specific event occurs. Unlike a traditional API call where one system actively requests data from another, a webhook “pushes” data in real-time. Imagine a postal service that automatically sends a notification every time a package reaches a new checkpoint. In HR, a webhook might fire when a candidate applies for a job, triggering an automated email confirmation, a task in a project management tool, or an update in a CRM. This event-driven communication is crucial for building responsive and dynamic automation sequences, such as instantly moving a candidate through a hiring pipeline or initiating an onboarding workflow immediately after an offer is accepted.

CRM (Candidate Relationship Management)

While traditionally associated with sales, a CRM in the HR context, often called a Candidate Relationship Management system, is a tool designed to manage and nurture relationships with potential candidates, similar to how sales teams manage leads. It helps recruiters build talent pipelines, track interactions, and engage with passive candidates over time, even before a specific job opening arises. Integrating a CRM with an ATS can provide a holistic view of candidate interactions, from initial outreach to application status, ensuring a personalized candidate experience. For automation, a CRM can trigger automated email sequences, reminders for follow-ups, or even initiate candidate assessments based on predefined criteria.

ATS (Applicant Tracking System)

An Applicant Tracking System (ATS) is a software application designed to manage the recruitment and hiring process. It handles everything from job posting and resume parsing to candidate screening, interview scheduling, and offer management. The ATS acts as the central hub for all active recruitment activities. Automation within an ATS can include automatically rejecting candidates who don’t meet minimum qualifications, scheduling interviews based on calendar availability, or sending automated communications to candidates at various stages of the hiring pipeline. Integrating an ATS with HRIS, background check providers, or assessment tools through APIs and webhooks significantly enhances efficiency and reduces administrative burden for recruiting teams.

HRIS (Human Resources Information System)

An HRIS is a software solution used by HR professionals to manage and automate core HR functions, including employee data management, payroll, benefits administration, time and attendance, and compliance. It acts as the central repository for all employee-related information post-hire. An effective HRIS provides a single source of truth for employee data, from their first day to their last. Integrating an HRIS with an ATS ensures a smooth transition for new hires from candidate to employee, automatically populating employee profiles with data collected during the recruitment phase. Automation here can include auto-enrolling employees in benefits, initiating payroll setup, or triggering performance review cycles.

iPaaS (Integration Platform as a Service)

iPaaS stands for Integration Platform as a Service, a cloud-based platform that provides tools and services for connecting various applications, data sources, and business processes. Rather than building custom integrations from scratch, iPaaS solutions offer pre-built connectors, visual workflow designers, and monitoring capabilities, making integration faster and more scalable. For HR, iPaaS platforms like Make.com are invaluable for connecting disparate HR tech tools—such as an ATS, HRIS, payroll system, and communication apps—without extensive coding. This allows HR teams to automate complex, multi-step workflows like onboarding sequences or data synchronization across systems, significantly reducing manual effort and integration costs.

REST API (Representational State Transfer API)

REST API is a widely adopted architectural style for designing networked applications, particularly web services. It’s stateless, meaning each request from a client to a server contains all the information needed to understand the request, and the server doesn’t store any client context between requests. Most modern HR tech applications use REST APIs because they are lightweight, flexible, and easy to use with standard web protocols. This makes it simpler for developers or iPaaS platforms to build integrations that allow an ATS to retrieve candidate information from LinkedIn, or an HRIS to update employee data in a third-party benefits portal, enabling seamless data flow across the HR ecosystem.

JSON (JavaScript Object Notation)

JSON is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is a common format for sending data between web applications and servers, especially when using REST APIs. Imagine a structured list where each item has a clear label and value, such as a candidate’s name, email, and resume URL. In HR tech, when your ATS sends applicant details to a background check provider via an API, that data is often formatted as JSON. Understanding JSON helps HR professionals grasp how data is structured and exchanged between their automated systems, ensuring data integrity and successful integrations.

XML (Extensible Markup Language)

XML is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. While JSON has become more prevalent for modern web services, XML is still used extensively, especially in older or more enterprise-level systems. Think of it as a detailed, hierarchical document structure. Some legacy HR systems, or industry-specific data exchanges (like certain payroll files or benefits enrollments), might still use XML to transfer data between applications. While not as common in new integrations as JSON, its presence means that HR professionals working with a diverse tech stack may still encounter XML when setting up or troubleshooting integrations with various vendor systems.

OAuth

OAuth (Open Authorization) is an open standard for access delegation, commonly used as a way for internet users to grant websites or applications access to their information on other websites without giving them their passwords. Instead, it issues tokens that grant specific permissions for a limited time. In HR, OAuth is critical for security when integrating systems. For example, when you connect an HR analytics dashboard to your HRIS, OAuth allows the dashboard to access specific data (like employee demographics) without ever seeing or storing your HRIS admin password. This provides a secure and granular way to manage permissions, protecting sensitive employee data while enabling necessary data sharing for automation and reporting.

SSO (Single Sign-On)

Single Sign-On (SSO) is an authentication scheme that allows a user to log in with a single ID and password to access multiple related, yet independent, software systems. Instead of having separate login credentials for the ATS, HRIS, payroll system, and learning management system, an employee or recruiter can use one set of credentials. SSO dramatically improves user experience by reducing login fatigue and simplifies IT management by centralizing user authentication. For HR tech stacks, implementing SSO enhances security, as it reduces the number of passwords to manage and often integrates with enterprise identity providers, streamlining access for employees to all their HR-related applications.

Data Migration

Data migration is the process of transferring data between storage types, formats, or computer systems. This typically occurs when an organization upgrades or replaces its HR tech systems, such as moving from an on-premise HRIS to a cloud-based solution, or consolidating multiple ATS instances into one. A successful data migration is crucial for maintaining historical records and ensuring business continuity. It involves careful planning, extraction, transformation (to match the new system’s format), and loading of data, often requiring significant data cleansing to remove inconsistencies or redundancies. For HR, precise data migration ensures that employee histories, performance reviews, and compensation data are accurately transferred to new platforms.

Cloud Computing

Cloud computing refers to the delivery of on-demand computing services—including servers, storage, databases, networking, software, analytics, and intelligence—over the internet (“the cloud”). Instead of owning and maintaining their own computing infrastructure, companies can access these services from a third-party provider. Virtually all modern HR tech, from ATS to HRIS and payroll systems, is cloud-based (SaaS). This offers significant benefits for HR: scalability to handle growing employee numbers, accessibility from anywhere, automatic updates and maintenance, and reduced upfront IT costs. Cloud computing forms the foundational infrastructure for integrating and automating today’s sophisticated HR tech ecosystems.

ETL (Extract, Transform, Load)

ETL is a three-step process used to integrate data from multiple sources into a data warehouse or another centralized repository.
1. **Extract:** Data is pulled from various source systems (e.g., ATS, HRIS, payroll).
2. **Transform:** The extracted data is cleaned, standardized, and modified to fit the target system’s format and requirements. This might involve converting date formats, combining fields, or removing duplicates.
3. **Load:** The transformed data is then moved into the destination system.
In HR, ETL is vital for building comprehensive analytics and reporting dashboards by consolidating data from different HR applications into a unified view. For instance, to analyze recruitment funnel efficiency alongside employee retention rates, an ETL process would gather data from the ATS and HRIS, cleanse it, and load it into a business intelligence tool.

Workflow Automation

Workflow automation involves using technology to automatically execute a sequence of tasks or steps in a business process, triggered by specific conditions. It eliminates manual intervention for repetitive, rule-based operations. For HR and recruiting, workflow automation is a game-changer. This could include automatically sending onboarding documents upon offer acceptance, creating a new employee record in the HRIS when a candidate status changes to “hired,” or scheduling follow-up emails for candidates who didn’t get an interview. By leveraging APIs, webhooks, and iPaaS platforms, HR teams can design sophisticated, multi-system workflows that save countless hours, improve accuracy, and enhance both candidate and employee experiences.

If you would like to read more, we recommend this article: The Automated Recruiter’s Keap CRM Implementation Checklist: Powering HR with AI & Automation