Hourly billing feels flexible right up until the invoice is twice the estimate and the product still is not done. When an MVP runs long, someone pays for it, and with hourly billing that someone is you.
How you pay for your build changes how the whole project behaves. Here is who carries the risk in each model, what a fair fixed-price deal looks like, and the contract red flags to catch before you sign.
How hourly billing works
You pay for time. If the work takes longer than expected, you pay more. Hourly makes sense when the work is truly open-ended: research, ongoing improvements or a product with no clear first version.
The risk for founders is that estimates drift, and there is no natural point where the spending stops.
How fixed-price billing works
You pay for an outcome. The builder agrees to deliver a written scope for a set price. If it takes longer, that is the builder's problem.
This only works when the scope is specific. "Build my marketplace" is not a fixed scope. "A provider can create a profile, a customer can search by zip code and send a booking request" is.
Every Thin Slice build is fixed price, with payments tied to working software you can click.
Book a free scoping call →What a fair fixed-price deal looks like
- A written scope listing what is included and what is not.
- Milestone payments tied to things you can see. For the Four-Week MVP, that is 40% to start, 30% at a working midpoint demo and 30% at launch.
- A change process. New ideas go on a v2 list with their own price, so the original agreement stays intact.
- A defined fix period after launch for bugs in the agreed scope.
- Clear ownership. You own the code, the hosting account and the data.
Red flags in any contract
- A large upfront payment with nothing to show until the end
- No written list of what is out of scope
- The builder owns the code or hosting account
- Vague answers about who will actually do the work
Frequently asked questions
Is fixed-price MVP development more expensive?
The quoted number may be higher than an hourly estimate, because the builder is taking on risk. The final cost is often lower, because hourly estimates tend to grow.
What happens if I want to change something during a fixed-price build?
In a well-run project, the change is written down with its own estimate. You decide whether to swap it for something of the same size or add it after launch.
How much should I pay upfront for an MVP?
Somewhere between a quarter and a half of the total is common. Be wary of paying most of the price before you see working software.
Know the full price before any code is written
Fixed scope, fixed price, paid 40% / 30% / 30% at milestones you can see. Book a free scoping call and you will have a written quote within two business days.
- Free 30-minute call
- Fixed price from $7,500
- Live in four weeks
- You own the code
I take on two to three builds at a time, so start dates fill up.