The verdict in three sentences
Under 25 staff, vertical SaaS (Karbon, Canopy, CCH Axcess) is almost always right: fast rollout, maintained integrations, predictable cost. Beyond 40 seats, custom becomes defensible because per-seat pricing grows faster than the flat maintenance fee of a proprietary platform. The real trade-off is not entry price but the 5-year TCO and how specific your workflows are.
The 2026 cost match
Vertical SaaS bills per active user. Custom is an upfront investment (CAPEX) plus monthly maintenance. Here are 2026 ballpark figures for a US firm, US/EU hosting included.
| Cost item | Vertical SaaS | Custom build |
|---|---|---|
| License / subscription | $50-100/seat/month | $0 (owned) |
| Initial development | $0 | $70,000-160,000 |
| Maintenance | included | $1,000-2,200/month |
| Hosting (US/EU) | included | $270-650/month |
| Integrations (tax/e-file/payroll) | standard | $9,000-22,000 (project) |
| Time to launch | 2-6 weeks | 16-24 weeks |
| Workflow customization | limited | total |
SaaS wins on speed and risk; custom wins on control and near-zero marginal cost per new hire.
Break-even by headcount
The decisive calc: at what headcount the 5-year custom TCO drops below SaaS. We assume SaaS at $75/seat/month and custom at $100,000 + $1,500/month maintenance.
| Headcount | SaaS 5 yrs | Custom 5 yrs | Break-even year |
|---|---|---|---|
| 15 seats | $67,500 | $190,000 | never (in 5 yrs) |
| 25 seats | $112,500 | $190,000 | ~year 6 |
| 40 seats | $180,000 | $190,000 | year 5 |
| 60 seats | $270,000 | $190,000 | year 3 |
| 80 seats | $360,000 | $190,000 | year 2-3 |
At 60 seats, custom saves about $80,000 over 5 years while removing per-seat dependency. Below 40 seats, stay on SaaS unless you have very specific workflow needs (multi-entity, proprietary review flows).
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Mini case study
Daniel runs a 55-person accounting firm in Miami. His vertical SaaS at $82/seat/month costs $54,120/year, or $270,600 over 5 years, with a 6%/year price increase announced. A custom platform (matter management, review, time billing, tax/e-file connectors) is quoted at $100,000 + $1,500/month maintenance, or $190,000 over 5 years. Net saving: ~$80,000 over 5 years, plus an asset that stays with the firm. Break-even hits in year 3; after that each new hire no longer adds ~$984/year in license fees.
FAQ
Is custom risky against an established vendor? Risk is managed with lots shipped every 2-3 weeks and a clear maintenance contract. Plan 16-24 weeks and a phased cutover with a one-period double-run.
Who maintains the tax, e-file and payroll integrations? In SaaS, the vendor; in custom, your provider via maintenance. Budget $9,000-22,000 to build them initially and confirm they are in the maintenance scope.
Where is the data hosted? Require US or EU hosting for compliance and professional confidentiality. Expect $270-650/month for managed hosting with backups and monitoring.
How long to pay back? For a 60-seat firm, break-even lands around year 3; at 40 seats, closer to year 5. Below that, SaaS stays cheaper.
Can we start hybrid? Yes: keep SaaS for core production and build custom only for differentiating modules (client portal, review workflows). Often the best cost/risk balance.
Let's scope your project. Send us your headcount, required integrations (tax/e-file/payroll) and indicative budget, and we will model the 5-year SaaS vs custom TCO for your firm. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
