Business problem
mobile.de had a working sell-to-dealer business. The open question was commercial, not visual: would people accept a valuation for a car they had never sold before, and trade it against the next one, in a single motion? Nobody knew what that proposition was worth to a seller.
My role
Prove or kill the proposition fast, with a squad of four. I owned the value case, the service architecture, the design, and the dev handover — and absorbed product management when the team grew rather than waiting for a hire.
Key actions
- Tested the value proposition on site, with real sellers. On-site smoke tests at dealer locations before the engineering team was fully staffed. Stated interest is cheap; behaviour at the point of handing over a car is not.
- Built the service blueprint across six teams and five platforms first. Not as a deliverable — as the artefact that made six teams agree on what the product was before anyone built it.
- Refused the design-system sidequest. Reused existing components so the team shipped rather than styled.
- Held the lean squad against scope pressure from adjacent teams until launch.
Outcome
Speed
MVP in
3 months
Live and connected to the wider marketplace.
Commercial
Conversion
improved
Iterated on the existing flow against measured data, not opinion.
What changed for the business
The trade-in became a permanent part of the mobile.de portfolio rather than an experiment that quietly stopped. The evidence came before the build, which is why there was something to keep.