109 CAS Ops: Build vs Buy Software

Should accounting firms build their own software instead of buying it? For years that was a joke for a firm this size—now we can stand up a working internal tool in an hour, and it changes the entire build-vs-buy question. 

In this episode of CAS Minute, Roman picks up where episode 107 ("services are the new software") left off and asks what firms should actually do about growing vendor risk now that AI tools like Claude and Cursor have collapsed the cost of building and maintaining internal tooling.

⏱️ Chapters

 00:00 – Should Firms Build Their Own Software?
 00:46 – People Are Coding Their Own Replacements Now
 01:57 – Why Vendor Risk Makes This Urgent
 03:32 – Commodity Infrastructure vs. Your IP Layer
 06:43 – What "Building" Actually Means in 2026
 07:54 – The Maintenance Tax
 08:40 – The Build-vs-Buy Filter
 10:54 – What This Means for Your Firm
 12:19 – Build the Brain, Rent the Plumbing

✅ Key Takeaways

• Building your own tools went from irrational to viable—AI collapsed the cost of building and maintaining internal tooling by an order of magnitude.
• Rent the commodity infrastructure: QBO, Gusto, Mercury, bank feeds, and payroll compliance are still the gold standard and not worth rebuilding.
• Build the IP and context layer that makes your firm you—close logic, client-specific rules, exception handling, and how you deliver advisory.
• "Building" in 2026 means internal tools, agents, and scripts on top of rented infrastructure—not shipping a SaaS product or hiring a dev team.

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Full Send | Accounting & Data

LinkedIn: Roman Villard, CPA
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