Build vs Buy · 14 min read

Custom ATS vs SaaS: What's Better for Your Company?

An honest comparison between building your own ATS and renting a SaaS solution. For HR managers and CTOs making a strategic choice.

Door Ingmar van Maurik · Founder & CEO, Making Moves

The ATS market is growing, but does it fit you?

There are hundreds of ATS systems on the market. Greenhouse, Lever, Workable, Recruitee, Personio, Teamtailor — the list is endless. They all promise the same thing: streamline your hiring process, manage candidates better, and reduce time-to-hire.

But the real question is: does a standard SaaS ATS fit your specific situation? Or are you paying monthly for features you don't need while missing the features you actually do?

In this article, we provide an honest comparison between a SaaS ATS and a custom-built system. No sales pitch — just a strategic analysis for HR managers and CTOs who want to make an informed decision.

What a SaaS ATS offers

A standard ATS gives you out-of-the-box functionality:

  • Candidate management and pipeline tracking — you see where each candidate is in the process
  • Job posting to job boards — publish to Indeed, LinkedIn, and other platforms with one click
  • Basic reporting — time-to-hire, source-of-hire, and other standard metrics
  • Email templates and scheduling — automated candidate communication
  • Compliance features — GDPR-compliant storage and deletion of candidate data

    • For companies making fewer than 50 hires per year with a relatively standard recruitment process, this is often sufficient. Implementation time is short (days to weeks), no technical team is needed, and costs are predictable.

    The hidden costs of SaaS

    But behind that predictable monthly invoice lie hidden costs many companies only discover later:

  • Per-user pricing that scales quickly as your team grows
  • Add-on modules for features you consider standard
  • Integration costs for connecting with your other HR stack
  • Data export fees when you want to switch vendors
  • Training costs with every major platform update

    • A recent analysis shows that the actual total cost of ownership for a SaaS ATS averages 40-60% higher than the advertised price.

    Where SaaS falls short

    Custom assessments

    Most ATS systems don't offer integrated custom assessments. You need to connect a separate tool — think TestGorilla, Harver, or SHL — which brings extra costs and integration issues. The result is a fragmented candidate experience: first apply in the ATS, then follow a link to an external assessment tool, and then results need to be manually or shakily synced back via API.

    With your own assessment system, you avoid this fragmentation entirely. Assessments become part of the flow, not an afterthought.

    AI functionality

    Many ATS vendors slap "AI" on their marketing, but actual functionality is limited. What they call AI is often nothing more than:

  • Keyword matching in CVs — no real semantic analysis
  • Simple ranking based on hardcoded criteria
  • Automated messages — useful, but not AI
  • "AI-powered" search that in practice is just full-text search

    • Real AI in hiring means predictive models that learn from your successful hires, bias detection, and continuous calibration. That requires access to your data and the freedom to train models on your specific context.

    Data ownership

    This might be the most underestimated problem with SaaS. Your candidate data, assessment results, hiring analytics, and success patterns sit with the vendor. Want to switch? You'll discover that:

  • Data export is limited to CSV files without relationships
  • Historical analytics are lost
  • Your built-up models and insights don't transfer
  • You essentially start from scratch with a new vendor

    • As we describe in our article on data ownership, your hiring data is a strategic asset. Giving it away to a vendor is comparable to outsourcing your customer data to a third party.

    Flexibility and customization

    Want a custom hiring flow? A specific scoring model for a particular department? Integration with your own BI tool or data warehouse? With most SaaS ATS systems, you're limited to what the vendor offers. Customization is restricted to:

  • Adjusting email templates
  • Modifying pipeline stages
  • Adding custom fields
  • Basic branding (logo and colors)

    • Fundamental changes to the flow, scoring logic, or data structure simply aren't possible. You adapt your process to the tool, instead of the other way around.

    When a custom ATS pays off

    Your own system is the better choice if you meet multiple of these criteria:

  • Volume: more than 100 hires per year, where efficiency gains become substantial
  • Specific flows: you have hiring processes that no standard ATS supports — think multiple assessment rounds, hiring committees, or custom scoring models
  • Integrated assessments: you want [assessments as a core part](/artikelen/generic-assessments-dont-work) of your hiring flow, not as a separate tool
  • Data ownership: you want full control over candidate data for compliance, analytics, or strategic purposes
  • AI with real impact: you want to train predictive models on your own data, not depend on a vendor's limited AI
  • Multi-entity or multi-brand: you recruit for multiple business units or brands with different flows

    • The build-or-buy decision matrix

    CriterionSaaS ATSCustom ATS

    |-----------|----------|------------|

    Implementation time1-4 weeks2-4 months Initial costsLow (€500-€2,000/month)Higher (one-time investment) Costs over 3 years€18,000-€72,000+One-time + minimal maintenance CustomizationLimitedUnlimited AI capabilitiesBasicAdvanced Data ownershipVendorYou ScalabilityVendor-dependentFully in your control Assessment integrationVia third partiesNative

    For a deeper analysis of this trade-off, also read our article on build vs. buy for hiring platforms.

    The investment compared

    SaaS ATS: ongoing costs

    A SaaS ATS costs €500-€2,000/month for a mid-market solution. Add assessment tools (€200-€500/month), extra integrations (€100-€300/month), and add-ons. Over 3 years, that quickly adds up to €30,000-€100,000 — without ownership of the data or the system.

    And every year brings price increases. The average annual price increase among SaaS ATS vendors is 8-15%.

    Custom ATS: one-time investment

    A custom system is a one-time investment. After the build, you have:

  • No ongoing license costs — only hosting and maintenance
  • Full control over features, data, and roadmap
  • A system that grows with your organization at no extra cost
  • The ability to train AI models on your own data
  • Full integration with your existing tech stack

    • The break-even point is typically at 12-18 months. After that, you save every year compared to SaaS.

    Real-world example: a tech scale-up

    A Dutch tech scale-up making 150 hires per year was using a combination of Greenhouse (€1,500/month), TestGorilla (€400/month), and various integrations. Total annual cost: €28,000+, excluding internal hours for management.

    After switching to their own hiring system:

  • Cost-per-hire dropped by 35% through integrated assessments and AI screening
  • Time-to-hire went from 42 to 24 days through automation
  • Quality of hires improved by 25% as measured by 6-month performance reviews
  • Full data ownership and custom analytics dashboards

    • Conclusion and key takeaways

    The choice between a SaaS ATS and a custom system depends on your situation:

    Choose SaaS if:

  • You make fewer than 50 hires per year
  • You have a standard recruitment process
  • You don't have a technical team for maintenance
  • You want to start quickly without a large investment

    • Choose custom if:

  • You make more than 100 hires per year
  • You want to integrate assessments and AI into your flow
  • Data ownership is important for your strategy
  • You want to build a defensible competitive advantage

    • The trend is clear: more and more companies serious about hiring as a strategic advantage choose their own system. The initial investment is higher, but the long-term ROI is unmatched.

    Want to know what a custom hiring system could mean for your organization? Get in touch for a free consultation or explore our AI hiring system solution.

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