Contents
- Y Combinator advises founders to target a functional MVP in 2-4 weeks, with most successful YC companies shipping their first usable product within 30 days.
- Stealth Labz tracked every commit across 10 production systems.
- The speed gain is not about working faster.
- For a first build with no existing foundation, plan for 3-4 weeks to a functional production system.
A production system built with AI-assisted development takes 5 days at maturity and 24 days for a first build, based on audited git data from Stealth Labz's 10-system portfolio shipped over 116 calendar days using the Compounding Execution Model (CEM).
Industry Benchmarks
Y Combinator advises founders to target a functional MVP in 2-4 weeks, with most successful YC companies shipping their first usable product within 30 days. Traditional software firms quote 3-6 months for a comparable production system. The gap between "MVP" and "production-ready" typically adds another 2-6 months in conventional development.
What the Audited Data Shows
Stealth Labz tracked every commit across 10 production systems. The build time compression follows a clear compounding curve:
| Project | Build Time | External Support Cost | Context |
|---|---|---|---|
| 1st system | 24 days | $7,995 | New vertical, new infrastructure |
| 2nd system | 25 days | $4,080 | Different vertical, early reuse |
| 4th system | 28 days | $1,680 | Complex build (7 integrations) |
| 5th system | 11 days | Included in flagship | Financial services vertical |
| 7th system | 16 days | $330 | New geography (US expansion) |
| 8th system | 9 days | $90 | Legal services vertical |
| 9th system | 5 days | $0 | Business reporting -- new vertical |
The 9th product shipped in 5 active days with zero external support cost. It entered a new vertical (business reporting), was revenue-ready at completion, and drew on infrastructure proven across the prior 8 systems.
Why Build Time Compresses
The speed gain is not about working faster. It is about working on less. At portfolio maturity, 95%+ of infrastructure components -- authentication, database schemas, admin interfaces, API structures, deployment pipelines -- came from the foundation built by prior projects. New systems only required the 5-20% of logic that made them different.
Concrete example: authentication that took days of work plus external support on the first project deployed in minutes on the ninth. That pattern repeated across every reusable component.
What This Means for Planning
For a first build with no existing foundation, plan for 3-4 weeks to a functional production system. For the second and third builds in adjacent verticals, plan for 2-3 weeks. By the fifth build onward with a mature foundation, plan for 1-2 weeks. At full maturity (8+ prior systems), 4-5 days to MVP is the validated benchmark.
The critical variable is not AI capability -- it is foundation depth. The operator who builds early compounds the longest.
Related: [FAQ #67 — Cost of Custom Software With AI]
References
- Y Combinator. "Startup School MVP Timeline Benchmarks." Recommended MVP development timelines.
- Keating, M.G. (2026). "Case Study: Five Days to Production." Stealth Labz. Read case study
- Keating, M.G. (2026). "Case Study: The Foundation Effect." Stealth Labz. Read case study