Menu
All templates
product · decision template

Build vs buy

Before engineering writes a line.

Build-vs-buy is usually decided by whoever is most excited to build, and re-litigated 18 months later by whoever inherits the maintenance. The async version forces both sides to put 24-month total cost of ownership and day-365 ownership on the table before engineering writes a line — so the decision survives contact with the on-call rotation.

The question

Should we build this in-house, or buy a vendor solution?

Opening context for contributors

Each side document: total cost of ownership over 24 months, who owns the integration on day 365, what we lose if the vendor changes pricing or shuts down, and what we lose if our build team gets pulled to higher-priority work.

What each contributor weighs

Ask everyone to put these on the table privately, before they see another contributor's position.

  • Total cost of ownership over 24 months — engineering time, not just license fees.
  • Who owns the integration and its on-call on day 365, by name or team.
  • What breaks if the vendor changes pricing, gets acquired, or shuts down.
  • What breaks if your build team gets pulled onto a higher-priority fire.
When to use this template
  • Vendor evaluation that drifted into 'we could just build this'
  • Mid-tier infra decision

How this decision usually goes wrong

  • Estimating the build at v1 scope and ignoring the long tail of maintenance, edge cases, and compliance.
  • 'We can just build it' enthusiasm with no named long-term owner.
  • Underweighting vendor lock-in — or over-fearing it for a commodity capability.
  • Comparing build cost to license cost instead of to the opportunity cost of the roadmap.

How to run this decision in 48 hours

  1. Open a room seeded with the question above. Set a 48-hour deadline.
  2. Paste the opening context — keep it short. Engineers will not read more than 300 words.
  3. Invite by email. Each contributor submits position + reasoning + risks privately, before seeing anyone else.
  4. Read the synthesis. Claude maps consensus, dissent, blind spots, and confidence.
  5. Decide and log. The synthesis is the decision-log entry — no separate write-up.
What a good outcome looks like

A synthesis that makes the 24-month TCO and the day-365 owner explicit for both paths, and surfaces the vendor- or staffing-risk the excited side glossed over.

Use this template Browse all

Related reading

Related templates

Pivot or persevere
When the metrics aren't lying anymore.
Adopt a new policy
Internal governance, externally auditable.