Imagine you’re setting up a new starter. Their details need to go into your HR system. Payroll needs the same information. The benefits platform needs some of it. Finance may need something else. Perhaps your time and attendance system needs to know about them too.

Suddenly, one employee record has to make its way around several different systems. If those systems are not connected, someone may have to enter the same information more than once, upload a spreadsheet or manually check that everything has been updated correctly. But what if the systems could simply talk to each other? That is where an API comes in.

An API, or application programming interface, is a way for different software systems to communicate with each other. An open API allows approved external systems or developers to access certain functionality or information and build integrations, subject to the software provider’s rules, permissions and security requirements.

If you’re not from a technical background, that might still sound like a lot of jargon. So let’s break down what an open API actually means for HR and payroll teams, and why it could matter when you’re choosing or reviewing your software.

What is an open API?

Put simply, an open API is a way for software systems to communicate with one another and exchange information or carry out actions.

Think about the information held in your HR system. You might have employee names, job details, start dates, salaries, absence information and more. Some of that information is likely to be needed elsewhere. Your payroll system might need an employee’s salary and bank details. Your benefits platform might need their personal information. A time and attendance system might need their working pattern.

An API provides a way for these systems to communicate rather than relying on someone to manually move information between them.

The word “open” does not mean that anyone can access your data. It does not make your HR system publicly available or give unrestricted access to employee information. Instead, an open API makes certain functionality available to approved external systems or developers. Access is still controlled through authentication, permissions and security measures.

When a software provider tells you that its system has an open API, it can sound like a straightforward tick in the box. But the phrase itself doesn’t tell you very much about what you can actually do.

An open API might allow you to connect with certain HR, payroll or finance systems, for example, but that doesn’t mean it will support every connection or every type of information you want to share. The provider decides which data and functionality its API makes available.

So, rather than simply asking whether a system has an open API, it is worth finding out what the API actually allows you to connect, what information it can share and what actions it can support. That is the information that will tell you whether the API is genuinely useful for your organisation.

How does an open API work?

Let’s go back to that new starter. You’ve added their details to your HR system and now need the relevant information to reach payroll. What happens next? You don’t need to understand the technical detail behind an API to understand the basic process:

1. One system sends a request. Your HR system requests that certain information is shared.
2. The API processes the request. It checks what has been requested and whether it is permitted.
3. The connected system receives the information or completes an action. The payroll system can receive the relevant employee information.
4. The information is shared according to agreed rules. Only the data and functionality permitted by the integration are made available.

The same basic process could apply when sharing absence information, updating employee details or passing time data into payroll. The important thing to remember is that this is a controlled exchange of information. An API does not simply give one system unrestricted access to another.

Why are open APIs useful for HR and payroll systems?

For HR and payroll teams, the real appeal of an API is not the technology itself. It is what better-connected systems can help you achieve.

Most organisations use several different workplace systems, each with its own job to do. HR manages employee information. Payroll handles pay. Recruitment manages candidates and new starters. Time and attendance records working hours and absence. Finance needs information for reporting and accounting. The more systems you have, the more opportunities there are for information to become duplicated, delayed or manually transferred.

Good software integration can help reduce some of that friction. For example, rather than asking someone to take new starter information from one system and enter it into another, a connection could allow the relevant information to move between them.

That can help with:

• Reducing duplicate data entry
• Improving data accuracy
• Saving administrative time
• Creating more connected workflows
• Reducing the risk of information being missed between systems
• Helping information move between systems more efficiently

And these benefits can add up. If your team is spending time checking spreadsheets, re-keying employee information or investigating why two systems contain different versions of the same data, improving the connections between those systems could remove some of that unnecessary work. Of course, an API is not a magic button. The integration still needs to be designed, configured and maintained properly.

Open API vs closed API: what’s the difference?

You may also come across the terms “closed API” or “private API”. The simplest way to think about the difference is in terms of who is allowed to use the API.

Neither approach is automatically better. The right option depends on the organisation, the systems involved, security requirements and the integrations you need. For an HR or payroll team, the more useful question is whether the approach supports the connections you need, rather than whether the software uses an open or closed API.

What can you integrate using an open API?

There is no single list of systems that can be connected using an open API. It depends on what each software provider makes available and what its API is designed to support.

For HR and payroll teams, potential examples include:

• Sending new starter information from an HR or recruitment system to payroll
• Sharing absence and time data with payroll
• Updating employee information across connected systems
• Connecting payroll with pension or benefits platforms
• Linking HR data with finance or reporting systems

So, for example, you might want an employee’s absence information to move from your HR or time and attendance system into payroll. Or perhaps you want information captured during recruitment to flow into your HR system when someone joins the organisation.

Whether you can do this depends on the individual systems involved, the information they make available and the actions their APIs support. That is why checking the detail behind an API matters more than simply seeing “open API” listed as a software feature.

What should you consider before choosing software with an open API?

If you’re choosing new HR or payroll software, it can be tempting to add “open API” to your list of requirements and move on.

But there is a much more useful set of questions to ask. Start with your own systems and processes. Which platforms need to communicate? What information needs to move between them? Where are your teams currently spending time transferring or checking data? Then look at what the API can actually support.

In particular, consider:

• Which systems need to connect? Think about your current technology landscape and the systems that need to exchange information.
• What data needs to be shared? Be specific. Is it employee details, salary information, absence data, working hours or something else?
• Does the API support the required data and actions? This is crucial. A system can have an open API without providing access to every piece of information or every function you need.
• How often does information need to be updated? Consider whether information needs to move regularly, at particular points in a process or only when someone makes a change.
• What security and access controls are available? Employee and payroll information needs to be handled appropriately, so understand how access is managed.
• Who will build and maintain the integration? Depending on the systems and processes involved, specialist support may be needed to create and maintain the connection.

Ultimately, “Does your software have an open API?” is only the starting point. The better question is whether it can support the way you need your systems to work together. If you are choosing integrated HR and payroll software, it is worth considering integration requirements alongside the functionality of the individual systems.

Do you need an open API for your HR or payroll systems?

Not necessarily.

Whether an open API is useful will depend on the systems you have, the information that needs to move between them and the processes you want to improve. If your HR, payroll and other business systems are already working well together, you may not need to make changes simply because another system offers an open API.

But if your teams are regularly entering the same information in several places, transferring spreadsheets between systems or manually checking that data has been updated, it is worth looking at how your systems could work together more effectively. This is where understanding your current processes is just as important as understanding the technology.

If you are considering the benefits of HR and payroll integration, start by looking at where information currently moves between systems and where there might be opportunities to make that process simpler.

How can Phase 3 help with integration?

Choosing software with an open API is one thing. Making your systems work together in a way that genuinely improves your processes is another. That is where the right integration approach matters.

At Phase 3, we help organisations look at the connections between their HR, payroll and wider business systems, identifying where integration can make processes more efficient and where additional support may be needed.

Our integration support can help you understand your existing technology, identify opportunities to connect your systems and support the implementation and ongoing management of those connections. The objective isn’t to connect everything simply because you can. It is to make the technology you already rely on work better together.

In conclusion

An open API is a way for approved software systems to communicate and share information or functionality. For HR and payroll teams, that can create opportunities to reduce manual administration and make information flow more efficiently between the systems you use every day.

But having an open API is not the end goal. What matters is whether the available integrations support your actual processes and requirements. Start with the problem you are trying to solve, understand how your systems need to work together, and then look at what the technology can make possible.