Plenty of quality teams run validation on tools they built themselves — a SharePoint site, a low-code app, a well-loved set of Excel templates with macros. It usually starts sensibly: the commercial options looked expensive, and the team knew exactly what they wanted.
The question worth asking honestly is not whether building works. It clearly can. It is what you have taken on, and whether you priced it.
What you take on when you build
A tool you built that supports GxP decisions is a computerised system like any other — except you are now the supplier as well as the user. Under GAMP 5 that generally makes it Category 5, the most demanding classification.
That means you own, and must evidence:
- A full specification and design, not just a working tool.
- Code or configuration review, with source control.
- Testing to Category 5 depth, including the negative cases.
- Change control on every subsequent tweak — including the quick fix someone makes on a Friday.
- Your own audit trail, access control and electronic signature implementation, meeting Part 11 properly rather than approximately.
- Business continuity when the person who built it leaves.
That last point ends more home-grown systems than any regulatory finding. See GAMP 5 categories.
When building is reasonable
- The tool does not hold GxP records or decisions. A planning tracker or a resourcing dashboard is not the same as a system holding executed protocols.
- Your process is genuinely unusual and you have tested that against reality — most processes that feel unique are ordinary processes with local vocabulary.
- You have real software capability, not one enthusiastic person: someone to maintain it, review changes and hand it over.
- The scope is small and stable. Narrow tools age well; ambitious ones accumulate obligations.
Note what is missing from that list: cost. Building to save licence fees is where the arithmetic usually goes wrong, because the licence is the visible cost and validation, maintenance and continuity are the invisible ones.
Comparing honestly
Put both options on the same page over five years, and include the lines people leave out.
- Build: development effort; Category 5 validation; every change revalidated; hosting and infrastructure qualification; maintenance and support; the cost of key-person risk; and eventual replacement, which is itself a migration and a decommissioning.
- Buy: licence; implementation and configuration; Category 4 validation, usually lighter because you can leverage qualified supplier evidence; assessing each vendor release for impact; and exit cost.
The comparison that decides it is rarely the first year. It is year three, when the built tool needs a change nobody remembers how to make, or the vendor ships a release you have to assess.
If you have already built one
Don't panic and don't rip it out on principle. Do establish its real status: is it GxP-relevant, is it validated to the category it actually falls in, who owns it, and what happens if that person leaves.
If it is sound, write down what makes it sound. If it is not, you have a choice between bringing it up to standard and replacing it — and that choice is now an informed one rather than a surprise during an inspection.
For evaluating the alternative, see how to evaluate GxP software and GxP software.
Where to go next
Explore GxP Copilot for AI-native validation, TraceDraft for source-traceable clinical documentation, or book a demo to see either on your own data.