Staffing Agency ATS Software: Contract Management, Planning and Invoicing in One System

Why staffing agency ATS software matters more every year, under regulation and time pressure

The staffing and secondment sector demands tight control and a clear line of sight. The Dutch WTTA 2027 sets strict requirements around registration and licensing, while NEN 4400 certification checks that your admin and payments are airtight. On top of that, the ABU-cao adds specific rules around phasing and inlenersbeloning, the Dutch principle of equal pay with the client's own staff. All of this feeds directly into your day-to-day processes.

Many agencies are still running on fragmented systems: contract management for placements sits in one tool, planning and timesheets in a second, and invoicing in a third. That gap creates administrative drift fast. A simple contract change doesn't automatically flow through everywhere it should, which creates unnecessary audit risk and eats up hours to fix by hand.

We see this problem constantly with growing teams looking for software for staffing agencies, where processes get more complex by the month. One central system settles that down, because every record lives in the same place and updates the rest automatically.

What sets staffing agency ATS software apart from a standard ATS

A standard ATS usually stops once a vacancy is filled. In staffing and secondment, that's where the real work begins: placements run on, and need ongoing contract management, timesheets and error-free invoicing.

A staffing-specific ATS links the candidate, the client, the assignment, the contract, the logged hours and the invoice into one continuous chain. That connection is the whole point of the system. You can always see exactly which terms someone is working under and which rate applies. Functionally, this looks much closer to dedicated agency software or staffing agency software than to a classic ATS.

The system also tracks the different phases under the applicable collective agreement, logs renewals, and keeps every agreement safely on record. Details such as inlenersbeloning and specific contract types become a standard part of the file. That makes the software fit not just for daily operations, but for a clean audit trail afterwards.

Key features of staffing agency ATS software in practice

Contract management and live phase tracking

Effective contract management starts with a clear, structured setup: contract type, agreed rate, client and term all get recorded. From there, the system automatically tracks end dates and phasing in line with the ABU-cao. The moment something changes, you immediately see what it means for that placement.

A reliable audit trail is essential here. It always shows who changed what, and exactly when. That's a real asset during checks and cuts out arguments after the fact.

Planning and timesheets tied directly to assignments

Both planning and timesheets need to be tied directly to the underlying assignment. Sickness, leave and rota changes all feed straight into hours worked, and from there into the final invoice. Without that link, administrative gaps appear fast.

A strong system processes these changes in real time, so hours and costs stay current and you avoid time-consuming corrections later. The end result is a much clearer view of both staffing levels and margin.

Invoicing for staffing agencies and smart margin control

Invoicing for staffing agencies calls for precise calculation. Rates, any surcharges and VAT all need to line up exactly with the signed contract and the applicable collective agreement. The system then calculates these amounts automatically from approved hours.

Because every piece of company data is linked, you get live visibility into the actual margin per assignment. That means you spot deviations far sooner, and can correct course before costs quietly get out of hand.

How staffing agency ATS software supports compliance and audits

Compliance runs through the entire staffing process. The incoming WTTA 2027, for example, requires crystal-clear records of placements and contracts. Alongside that, an ATS built for NEN 4400 continuously checks that your admin and outgoing payments are correct. It's essential that the system stores all of this logically and surfaces it clearly.

Identity verification against the Dutch BSN (citizen service number) plays a major role here too. Sensitive personal data needs to be stored securely and only accessible to authorised users. Key documents, such as proof of identity, must stay fully auditable, without any risk of a data leak.

In safety-critical sectors such as engineering and healthcare, extra requirements apply on top of that. Sector-specific certificates and qualifications always need to stay current. The system tracks these expiry dates and flags a warning in good time before a document lapses, so you're always ahead of any external inspection.

Integrations that genuinely move the needle in staffing agency ATS software

A staffing agency rarely runs on a single piece of software, which is exactly why smart integrations matter. A connection to AFAS, Visma or Nmbrs, for example, means current pay data and key contract details flow automatically between departments.

A genuinely good integration always works both ways: changes in payroll flow straight back into the system, and vice versa. That cuts a large amount of manual work and rules out human error. Native integrations are far more reliable here than loose exports, because the data stays in sync in real time.

Where a staffing ATS stops, and proactive outreach takes over

A modern ATS brings real structure to your internal processes and takes a lot of weight off admin and compliance. New, high-calibre candidates don't just appear on their own, though, which is why active outreach still matters.

Using personalised LinkedIn InMails as a strategy lets you reach the right candidates significantly faster. That matters most for scarce profiles in a tight labour market, where speed decides who gets the placement. The ATS handles the complex admin in the background, while smart outreach keeps new talent flowing in.

Want to know exactly which approach fits your own way of working? Start by using our tool to compare different solutions. To see how successful teams combine both in practice, go and browse real case studies, where you'll see watertight admin and targeted sourcing running side by side.

Checklist for choosing the right staffing agency ATS software

• Contract management: every active contract, past renewal and full history stored securely and visible instantly.
• Collective agreement support: the different phases and complex rules under the ABU-cao tracked fully automatically by the ATS.
• Full compliance: broad support for the WTTA 2027, NEN 4400 requirements within the ATS, and highly secure BSN verification.
• Planning and timesheets: a direct, seamless link to assignments, so logged hours are accurate down to the minute.
• Invoicing for staffing agencies: automatic rate calculations and a clear, live view of margin per client.
• Smart integrations: stable, reliable connections with payroll systems such as AFAS and Nmbrs, removing manual handovers entirely.

Want to turn this into practice for your own organisation? The advice is simple: get in touch. We'll take a critical look at your current processes together and map out exactly where the biggest efficiency gains are waiting.

Frequently asked questions about ATS software for staffing agencies

What's the main difference between a standard ATS and staffing software?
A regular ATS focuses mainly on attracting and selecting new talent. Staffing software, or dedicated software for a staffing agency, also gives you full support for contract management, resource planning, timesheets and final invoicing. That makes these systems especially well suited to candidates on placements that run for an extended period.

Does a staffing ATS need to formally comply with the WTTA 2027 itself?
The software itself doesn't need its own licence for this. It does act as a critical tool for recording all the required company data correctly and securely, so your own organisation meets the strict regulation with ease and comes through complex audits successfully.

Do you need a separate CRM alongside the ATS?
That depends heavily on how your organisation works. Many modern systems already combine candidate and client management effectively in a single platform. What matters most is that the data stays centralised, so you never run into mismatches between separate systems.

Why does a direct payroll integration matter so much?
A smart integration with systems such as AFAS or Nmbrs means essential pay and contract data updates automatically in the background. That rules out human error and saves your team many hours of admin every week.