Implementing or switching an ATS: the vendor-neutral guide

Implementing an ATS takes three to six months on average, and anyone doing it without external guidance quickly spends 200 to 400 internal hours (recruitmenttraining.pro, 2026). Yet in practice it rarely comes unstuck on the software itself, but on three underestimated elements: data migration, integrations and adoption. This guide is vendor-neutral — we do not sell an ATS and have no preferred deal — and walks through the entire process: from choosing in a market of 45 providers to go-live, including what the GDPR says about the candidate data you bring along.

How long does an ATS implementation take?

Three to six months is the average lead time for an ATS implementation, depending on the complexity of your organisation (recruitmenttraining.pro, 2026). Small organisations with a standard setup can go live in four to six weeks; agencies with custom work, multiple integrations and a serious data migration are at the top of the range. If you opt for a do-it-yourself approach, count on 200 to 400 hours of internal time (recruitmenttraining.pro, 2026) — hours your recruiters are not spending on placements.

The phases are practically the same with every vendor; what differs is where things go wrong:

The rest of this article follows those phases, with the emphasis on the three where implementations really come unstuck: data, integrations and adoption.

Choosing from 45 providers without getting lost

The Dutch market counts 45 ATS providers, roughly split between systems for corporate recruitment and systems for agencies and staffing firms (recruitmenttraining.pro, 2026). That choice overload is the first pitfall: anyone trying to compare all 45 ends up comparing demos instead of workflows. So first narrow down on your own situation — what type of organisation are you, what demonstrably needs to improve — and only then on features. Which systems you come across most often in the Netherlands and how they compare, you can read in What is an ATS?; our free ATS selection tool asks you the narrowing questions.

Four selection criteria that rarely come up on their own in demos, but make the difference later:

• Connectability. Does the system have an open, documented API and existing integrations with your back office? This determines how much manual work you can later automate away around it.
• Exportability. How do you ever get your data back out? A vendor that only offers PDF exports makes your next switch needlessly expensive.
• Pricing model. Per user, per module or per placement? Work the model through against your growth over three years, not against your team of today.
• Roadmap and support. Is the system actively developed and is there support that knows your industry?

Data migration: the real work

Data migration is the biggest time sink in practically every ATS implementation — preparation, migration and training together are the heaviest items in the process (recruitmenttraining.pro, 2026). The temptation is to bring everything along: ten years of candidates, every note, every document. Do not do that. A migration is not a move but a renovation: the moment to decide what your new system should hold, and what it should not.

The approach that works: clean up first (duplicate profiles, empty records, candidates you should have deleted long ago under the GDPR — see below), then record per field where it lands in the new system, and after that run a test migration with a subset before you transfer the whole database. Validate the test set manually: are the phone numbers correct, are CVs attached to the right profile, are statuses translated logically? Finally, plan a short freeze period around the definitive migration during which no one works in the old system anymore — otherwise two versions of the truth arise and the de-duplication starts all over again.

Integrations: plan them from day one

Integrations determine whether a new ATS makes the manual work disappear or merely moves it — so plan them in the selection phase, not after go-live. An ATS that is not connected to your back office creates precisely the leaks you wanted to close with the switch: placements that go to invoicing by hand, clients tracked in three places, reports built weekly by hand.

Before you choose, take stock of which connections you need: job boards and multiposting, mail and calendar, time tracking, accounting and a possible dashboard on your pipeline. Check per connection whether a standard integration exists, or whether it can be done via a tool such as Make, Zapier or Power Automate — and for the more complex flows what the API allows. A custom integration costs roughly €1,500–€15,000; in What does an API integration cost? we break that down, and on our integrations pages you can see per system what is possible. In the demo, do not ask the vendor whether there is an API, but for its documentation — that single request separates open systems from closed systems faster than any checklist. How you then automate the process around it, you can read in Automating recruitment: the playbook for agencies.

Adoption: the system is only finished when the team uses it

An ATS implementation succeeds or fails on adoption, not on technology: a system that is half used is not a half success but a complete failure, because no one trusts the data in it anymore. Many organisations underestimate this — an implementation is more than installing software; it requires revising your process, training and adjusted working agreements (recruitmenttraining.pro, 2026).

Three things that make the difference. One: appoint a key user per team who helps think about the setup and later fields the questions — adoption is contagious when the team's informal authority leads the way. Two: train on the process, not on the screens ('this is how you process a placement' instead of 'this is the placement screen'). Three: agree the one-system rule — if it is not in the ATS, it does not exist — and actively measure on usage in the first months: are statuses being kept up to date, are there notes in it, do placements run through the system? What you measure there is immediately the basis for your recruitment KPIs.

GDPR: which candidates are allowed to come along?

Not your entire database is simply allowed to come along to the new system. The Dutch Data Protection Authority (Autoriteit Persoonsgegevens) applies as a rule of thumb that application data must be deleted no later than four weeks after the end of the procedure; only with the candidate's consent may you keep it longer, with up to one year considered reasonable. Candidates for whom you no longer have valid consent therefore do not belong in your migration database — however full the portfolio may feel.

In practice this means: use the migration as a clean-up moment. Delete or anonymise expired profiles, and send borderline cases a re-confirmation request before the switch — those who consent come along, those who do not respond do not. In the new system, set up automatic retention periods and deletion rules straight away, so this is the last manual clean-up. And conclude a data processing agreement with the new vendor before a single candidate is transferred.

Switch or stay?

The decision rule is simple: switch if the pain lies in the system itself, stay and integrate if the pain lies in the connections. Missing core functionality, a closed API, a vendor no longer developing the product — those are reasons for a switch. But retyping work, loose spreadsheets, manual invoicing and reports rebuilt every week are not: you solve those with an integration on your current ATS faster and cheaper than with a three-to-six-month implementation process plus hundreds of internal hours.

Not sure which situation applies to you? How we help agencies with integrations and automation around their existing (or new) ATS, you can read on IT & automation for recruitment. The free Operations Scan maps out in advance exactly where the manual work sits — before you make a decision of months on a gut feeling.

Further reading

• Free ATS selection tool
• Recruitment KPIs: which numbers do you steer on as an agency?
• What is an ATS — and how do you automate your recruitment agency?
• Automating recruitment: the playbook for agencies (2026)
• What does an API integration cost?
• IT & automation for recruitment agencies

Frequently asked questions

Written by Hugo Eleveld · Updated June 2026. This article is informational; for tailored advice book an intro call.